Regulations (Preambles to Final Rules) - Table of Contents|
| Record Type:||Occupational Exposure to Cadmium|
| Title:||Section 9 - IX. Summary and Explanation of the Final Cadmium Standard for General Industries, Agriculture, and Maritime.|
IX. Summary and Explanation of the Final Cadmium Standard for General Industries, Agriculture, and Maritime.
OSHA believes that, based on currently available information in the cadmium rulemaking record, the requirements set forth in this final rule are necessary and appropriate to provide adequate protection to employees exposed to cadmium.
The language of the standard and the order of the various provisions are consistent with other recent OSHA health standards, such as the formaldehyde and benzene standards. OSHA believes that a similar style should be followed from standard to standard to facilitate uniformity of interpretation of similar provisions. Some modifications have been made to this standard in response to the particular nature of cadmium as an occupational health hazard and to experience previously gained with other health standards. Section 6(b)(5) of the Act states that health standards shall also be based on "experience gained under this and other health and safety laws."
Scope and Application: Paragraph (a).
This final cadmium standard applies to all occupational exposure to cadmium and all cadmium compounds, in all forms, including fume and dust. The addition to the final standard of the words "all cadmium compounds" and "all forms" only clarifies and makes explicit the broad scope that was intended and implicit in the proposal. The standard applies to all industries covered by the OSH Act, including shipyards, marine terminals, longshoring, and agriculture, except the construction industry. OSHA is amending Parts 1915, 1917, 1918 and 1928 to apply this standard to these industries. Exposure to cadmium in the construction industry is covered by a separate cadmium standard for that industry, 29 CFR 1926.63. All occupational exposures to cadmium are covered, because the risk from exposure to cadmium is dependent on the extent of exposure and not on the segment of industry where the employee may be employed.
The categorization of workers who are covered by this standard is slightly different from the categorization used in the proposal (55 FR 4052). The explanation of the need for this change is discussed under the section on the Regulatory Impact Analysis.
OSHA estimates that about 524,816 workers are potentially exposed to cadmium. Of these, approximately 70,000 workers are potentially exposed in the construction industry. Of the remaining 455,000 workers, approximately 89,250 are exposed in nine industries where cadmium exposure is more prevalent. These nine are: nickel-cadmium (Ni-Cd) battery manufacturing, zinc/cadmium production, cadmium pigments production, lead smelting/refining, cadmium plating, plastic stabilizer production, dry color formulation, electric utilities, and iron and steel. (Table VIII-A1, Office of Regulatory Analysis, Regulatory Impact Assessment Section).
The remaining 366,000 employees covered by the standard, who constitute about 70% of all employees potentially exposed to cadmium, are in 10 separate occupations common to approximately 98 industries. These occupations involve exposure to cadmium during the handling, heating, or other processing of cadmium or its compounds. The occupations are: chemical mixers, electroplaters, furnace operators, kiln/kettle operators, heat treaters, equipment cleaners, metal machinists, painters, repair/utility workers, and welders/solderers. The industries in which one or more of these occupations are found include foundries, machinery production, electronic components production, automotive repair, photographic equipment production, aircraft and ship building, paper production, glass and pottery production, and air transportation, among others. (Table VIII-A1, Office of Regulatory Analysis, Regulatory Impact Assessment Section).
The only important issue raised in the rulemaking concerning the scope of the proposed cadmium standard was whether a separate standard should apply to the construction industry. Several commenters favored covering the construction industry in the general industry standard (Exs. 19-8; 19-21; 57). However, a representative of OSHA's Advisory Committee on Construction Safety and Health testified in opposition to extending the general industry standard to construction and in favor of a construction-specific standard that would address the unique conditions in that industry (Tr. 6/13/90, pp. 4-16).
OSHA agrees with the Advisory Committee that such a standard is needed. OSHA is therefore promulgating a separate standard for the construction industry that is adapted to the particular conditions of that industry and assures protection to construction workers that, to the extent feasible, is comparable to the protection afforded workers in general industry by this standard. OSHA does not understand the comments favoring inclusion of the construction industry within the scope of the general industry standard as opposed to this result. The primary concern reflected in those comments is that construction workers be assured prompt and adequate protection from excess exposure to cadmium. OSHA believes that this can be accomplished more effectively by promulgation of a comparably protective, construction-specific standard in conjunction with the promulgation of a general industry standard that excludes the construction industry. Based upon the record evidence in this rulemaking, including pre-hearing comments submitted by the Advisory Committee concerning special working conditions in the construction industry, testimony at the public hearing by a representative of the Committee, and the draft of recommended modifications to the proposed rule submitted by the Committee (Exs. 8-665; 14-5; 53), OSHA has developed a separate and somewhat modified cadmium standard for the construction industry, 29 CFR 1926.63. A full discussion of the development of that standard can be found in the preamble to the construction standard.
Other issues were raised in the rulemaking that have some relevance to the scope of the standard, but these issues are best addressed elsewhere in this preamble. For example, a dispute about the regulation of cadmium fume and dust is not a dispute about whether both should be regulated in this standard. Rather, the dispute only concerns whether dust and fume should be regulated differently as they were in the pre-existing OSHA PELs. (For a complete discussion of this issue, see Section IX -Summary and Explanation under (g), below, and Section V - Health Effects.) Similarly, a discussion of the carcinogenicity and toxicity of cadmium pigments is provided under Section V - Health Effects and Section VI - Quantitative Risk Assessment.
Definitions: Paragraph (b)
Action level. The final standard retains the same definition of "action level" (AL) incorporated in the proposal for the permissible exposure limit (PEL) of 5 ug/m(3). The action level is defined as an airborne concentration of cadmium of 2.5 ug/m(3), calculated as an 8-hour, time-weighted average (TWA).
The action level provides the airborne exposure of cadmium at or above which medical surveillance, air monitoring, and the provision of a respirator to any employee who requests one are required. Other requirements of the standard are not triggered until exposures exceed the PEL. Where exposures are determined to be below the action level, no compliance activities are required of the employer, except those required by paragraphs (d)(4), (m)(3), and (m)(4) of this standard.
In this and other standards the action level has been set at one-half of the PEL (e.g., Arsenic Final Standard 29 CFR 1910.1018; Benzene Final Standard, 29 CFR 1910.1028). The action level provides a mechanism to tailor certain requirements of the standard to a minimum level of employee exposure to cadmium by triggering preventive action by the employer for employees who face exposure at or above that level. The use of the action level to trigger various provisions of the cadmium standard is consistent with other final OSHA health standards, (e.g., Asbestos, 51 FR 22612, June 20, 1986; Benzene, 52 FR 34460, September 11, 1987; Formaldehyde, 52 FR 4668, December 4, 1987; Ethylene Oxide decision (796 F.2d 1479 (D.C. Cir, 1986) and, Public Citizen Health Research Group v. Tyson, 796 F.2d 1479 (D.C.Cir, 1986), and Acrylonitrile, 43 FR 45809, October 3, 1978).
This substantive consistency provides administrative consistency and continuity to employers in developing and implementing compliance strategies for this and other applicable OSHA health standards at individual worksites. In addition, use of an action level has been found to encourage employers, where feasible, to lower exposure levels to below the action level to avoid the added costs of required compliance with provisions triggered by the action level.
As exposures are lowered, the risk of illness among workers also decreases. Cadmium accumulates in the body over time. Obviously, cadmium accumulates more slowly at lower exposure levels. (See Section VI, Quantitative Risk Assessment.) When exposure measurements are below the action level, the employer can be reasonably confident that an employee will not be overexposed. Because of the somewhat variable nature of employee exposures to airborne concentrations of cadmium, maintaining exposures below the action level provides considerable assurance to the employer that employees will not be overly exposed to cadmium; i.e. over the permissible exposure limit (PEL). [For a more detailed discussion of the concept of an action level, see, for example, the Acrylonitrile preamble (43 FR 45809, October 3, 1978), and the Ethylene Oxide preamble (48 FR 17284, April 21, 1983 (Ex. No. 159-49A)).] The action level serves other functions, for example, it defines the coverage of medical surveillance. For employees exposed to cadmium at or above the action level on 30 or more days per year (twelve consecutive months), employers are required to provide a medical surveillance program. In addition, the employer is also required to provide medical surveillance to all employees who prior to the effective date of this section might previously have been exposed to cadmium at or above the action level by the same employer for an aggregated total of more than 60 months.
As discussed under (l) in this Summary and Explanation, the medical surveillance program triggered by the action level is targeted to the organ system most sensitive to non-carcinogenic cadmium toxicity, the kidney. The medical surveillance program will facilitate the identification and reduction of kidney dysfunction and is expected to result in an overall reduction of cadmium exposure and of all cadmium-related illnesses.
According to OSHA's risk assessment, which does not take into account further reductions in risk attributable to the ancillary provisions of this standard, there appears to be continuing significant cancer risk at the PEL. Under the recent asbestos decision (Building and Construction Trades Department, AFL-CIO vs. Brock, 838 F.2d 1258, D.C. Cir. 1988), where such continuing significant risk appears to exists, OSHA should use its legal authority to impose additional requirements on employers to further reduce risk when those requirements will result in a greater-than-de-minimis incremental benefit to workers' health. OSHA concludes that the action level will result in a very real and necessary further reduction in risk over that provided by the PEL alone. The action level provides added employee protection while increasing the cost-effectiveness and performance-orientation of the standard.
The main issue raised in the rulemaking regarding the action level was whether OSHA should set it at the conventional level of one-half the PEL. OSHA had considered setting the action level still lower in the proposal (55 FR 4104-05) to expand coverage of workers for whom medical surveillance would be required. The Agency decided to set the PEL at 5 ug/m(3), the higher of the two proposed alternatives and to set the action level at half the PEL, being 2.5 ug/m(3).
One commenter, representing Duke Power Company, opposed setting the action level at less than half the PEL because it would require medical surveillance for a significant number of workers who do not need it (Ex. 19-18). OSHA agrees that setting the action level at less than half the PEL primarily to identify more workers who had been excessively exposed in the past would be an overly broad mechanism for accomplishing a relatively narrow, if important, purpose. Instead, as discussed below, OSHA relies in this final standard on a specific provision requiring the employer to also provide medical surveillance to certain employees who prior to this standard were exposed to cadmium. This provision triggers medical surveillance independently of the current action level. Thus, in addition to having to provide medical surveillance to certain employees who are currently exposed, employers also are required to provide medical surveillance to employees who were or might have been previously exposed at or above the action level by the current employer for a specified period of time, regardless of whether they are currently exposed at or above the action level.
OSHA received numerous comments on the need to protect veteran employees. While some commenters were of the opinion that veteran employees would not need coverage because good medical evaluations will identify older workers at risk (e.g., Ex. 19-31), others were of the opinion that specific coverage was necessary (Exs. 19-23; 123). OSHA decided to set the action level at half the PEL, as proposed, and to establish a separate provision to address the issue of veteran employees.
Employee exposure is defined as the exposure to airborne cadmium that would occur if the employee were not using respiratory protective equipment. This definition is intended to apply to all variations of the term "employee exposure" that have essentially the same meaning, such as "exposed employee" and "exposure." The definition is consistent with OSHA's previous use of the term in other standards (Asbestos, 29 CFR 1910.1001; Benzene, 29 CFR 1910.1028, Ethylene Oxide, 29 CFR 1910.1047). Employee exposure or "exposed" means the level of cadmium that an employee is subjected to in the course of employment.
Final medical determination is the physician's written medical opinion of the employee's health status. Under paragraphs (l)(3)-(l)(12), the written medical opinion of the examining physician is the "final medical determination." Where either multiple physician review or the alternative physician determination mechanism has been invoked under paragraphs (l)(13) or (l)(14), respectively, the final medical determination is the final, written medical finding, determination or recommendation that emerges from that process.
The terms "Assistant Secretary", "authorized person", "Director", "high-efficiency particulate absolute [HEPA] air filter", and "regulated area" are defined in this final standard essentially as proposed. These definitions are based on OSHA's previous experience and are consistent with OSHA's use of these terms in other health standards. These definitions generally have not been commented upon.
Permissible Exposure Limit (PEL): Paragraph (c).
Employers are required to assure that no employee is exposed to an airborne concentration of cadmium in excess of the permissible exposure limit (PEL) of 5 micrograms of cadmium per cubic meter of air (ug/m(3)).
In its proposed rule, OSHA proposed two kinds of PELs, an 8-hour, time-weighted-average permissible exposure limit (TWA PEL) and an excursion limit (EL), a limitation on short-term exposures averaged over a 15-minute period (55 FR 4105-05). For the TWA PEL, OSHA proposed two limits: 1 and 5 ug/m(3). On the one hand, OSHA proposed a PEL of 1 ug/m(3) to substantially lower risk of death from cancer (55 FR 4076, Table VI-C and 4080, Table VI-G). On the other hand, OSHA proposed a PEL of 5 ug/m(3) due to serious concerns about the technological feasibility of the lower PEL (55 FR 4053). OSHA proposed an EL on the basis of good industrial hygiene practices (55 FR 4105) (Ex. 8-664).
OSHA's risk assessment indicates that significant risks of cancer and kidney damage exist at the prior PELs (100 ug/m(3) for fume and 200 ug/m(3) for dust) for cadmium. There is a consensus among participants in the rulemaking that these PELs are much too high to protect the health of exposed employees. The Cadmium Council, a trade association whose members are producers and commercial consumers of cadmium or of other metals from ores containing cadmium, indicated that there is some broad agreement among its constituents that, leaving feasibility considerations aside, the PEL should be set no higher than 20 ug/m(3)(Ex. 19-43). The disagreement arises over whether the health science data requires that the PEL be set below 20 ug/m(3) and, if so, how far below. Most of the public health officials, unions, scientists and physicians who participated in the rulemaking conclude that the PEL should be set between 1 ug/m(3) and 5 ug/m(3) (Ex. 19-8, 123; Tr. 6/7/90, pp. 72-200; Ex. 57; Trs. 7/17/90, pp. 51-217; 6/6/90, pp. 69-119; 7/17/90, pp. 258-277; Ex. L-140-50). Some industry representatives and experts who testified and commented for industry generally believe the health evidence requires that the PEL be set at 20 ug/m(3) (Exs. 19-43, 77, 119), though other industry sources support a PEL of 10 ug/m(3) or lower (Exs. 19-13, 19-24, 19-36, 19-31). Thus, disagreement in the rulemaking about the level at which the PEL should be set to adequately protect workers is focused primarily on the range between 1 ug/m(3) and 20 ug/m(3), although some commenters recommended establishing a higher PEL (Ex. 105), especially for pigment workers (Ex. 19-17, 19-40). Setting aside the issue of pigment workers who are covered by this standard, (See Health Effects Section), OSHA, therefore, focused primarily on levels between 1 ug/m(3) and 20 ug/m(3) in establishing the PEL (Ex. 19-43).
Establishing a PEL anywhere within that range would greatly reduce the excess risks of cancer and kidney damage from the current PELs. The lower the level selected, the greater the reduction in risk. However, even at the low end of this range of PELs, some risks above one in one thousand would remain if OSHA did nothing other than impose a new PEL. As a result, under the asbestos decision (Building and Construction Trades Department, AFL-CIO v. Brock, 838 F.2d 1258 (D.C.Cir, 1988)) and the Ethylene Oxide decision (Public Citizen Health Research Group v. Tyson, 796 F.2d 1479 (D.C.Cir, 1986), OSHA is under a legal obligation to take additional actions to the extent feasible to require employers to further reduce risk. Consequently, OSHA does not rely exclusively on the PEL to eliminate significant risk. The Agency relies, as well, upon other provisions of the final standard, such as the action level (AL), the very strict, multi-layered medical surveillance program, and the medical removal protection provisions, among others, to eliminate significant risk. In fulfilling this obligation, the Agency has discretion to determine which particular, additional actions should be required of employers.
The Agency, however, decided not to include an excursion limit (EL) in the cadmium standard for two reasons. First, unlike OSHA's benzene rulemaking (52 FR 34460, 34532, Sept. 11, 1987), no evidence was submitted to the record to persuade the Agency that an EL was needed to protect employees from short term excursions as low as the proposed EL. Moreover, although in theory imposing an EL might further lower the daily dose of cadmium to which the employee is exposed, there is little or no record evidence supporting this supposition. Under the standard, employers already are likely to seek to control exposures to levels below the PEL which also will minimize the occurrence of high exposure excursions.
Second, in some plants, employees appear to be exposed to cadmium only intermittently and for short periods but not infrequently at levels exceeding the proposed EL. For these users, compliance with an EL might be infeasible (Ex. 19-24) or might require the expenditure of considerable resources without providing much additional protection to workers (Tr. 6/12/90, pp. 21-22; Ex. 19-5). These resources could more effectively be allocated to other forms of worker protection.
Without better justification for an EL in general, OSHA does not feel free to impose an EL. OSHA understands that, notwithstanding the absence of evidence that cadmium-induced diseases are dose-rate dependent and notwithstanding the likelihood that, even without an EL, employers will seek to control excursions, the opinion of the Court of Appeals for the D.C. Circuit in Ethylene Oxide (EtO) might still be read as requiring OSHA to impose an EL, when feasible, to reduce remaining significant risk (EtO decision (Public Citizen Health Research Group v. Tyson, 796 F.2d 1479 (D.C.Cir, 1986). However, OSHA does not believe the court in the EtO case intended to legally compel the Agency to select a particular method among the number of ancillary provisions available to reduce remaining significant risk. On the contrary, OSHA understands that decision as leaving the Agency the choice of which methods to adopt to achieve its legal obligation to reduce remaining significant risk. Thus, while the court did say that "[i]f in fact a STEL [or an EL] would further reduce a significant health risk and is feasible to implement, then the OSH Act compels the agency to adopt it...." (emphasis in the original), it then parenthetically added, "barring alternative avenues to the same result." 796 F.2d at 1505. In the cadmium standard, OSHA has chosen to follow "alternative avenues to the same result."
Regarding the disagreement in the rulemaking about the level at which the PEL should be set to adequately protect workers, OSHA has decided to set the PEL at 5 ug/m(3). Excluding partial bans on cadmium in Sweden and Germany, this is the lowest PEL in the industrialized world. There are two main reasons for this decision. First, the health science data in the record considered as a whole indicate that to eliminate significant risk the PEL should be set no higher than 5 ug/m(3)(Ex. L-140-50) (See sections on Health Effects and the QRA). At a PEL of 5 ug/m(3), OSHA is assured that the Agency is not regulating an insignificant excess risk of cancer or kidney damage. Estimates of risks for both kidney damage and lung cancer at a PEL of 5 ug/m(3) generally are similar and complementary. On the other hand, along with the ancillary provisions of the standard, a PEL of 5 ug/m(3) appears to reasonably protect cadmium exposed workers from a significant risk of material impairment of health.
Second, a PEL of 5 ug/m(3) appears to be at or very near the limits of technological feasibility for many workers in industries where there is no separate engineering control air limit (SECAL). Setting the PEL lower would require many more of these workers to wear respirators full time. For example, based on estimates in the proposal, if the PEL were set at the lower of the two proposed alternatives, 1 ug/m(3), approximately 37% of these exposed employees would be expected to have to wear respirators (55 FR 4097-98, Tables VIII-C and VIII-D). As OSHA indicated in the proposal, such heavy reliance upon respirators would raise extremely serious questions about the technological feasibility of achieving the PEL by engineering and work practice controls. By contrast, at a PEL of 5 ug/m(3), only approximately 1% of these employees would have to wear respirators (55 Fr 4097-98, Tables VIII-E and VIII-F). Although estimates of respirator usage required at a PEL of 5 ug/m(3) are higher in the final standard (RIA, Table VIII-C46) than in the proposal, OSHA continues to expect that the number of employees required to wear respirators at a PEL of 1 ug/m(3) would be much higher than at 5 ug/m(3).
Regarding the feasibility issue, OSHA considered the main arguments made by rulemaking participants in opposition to the proposed PEL of 5. The Cadmium Council and some of its members opposed a PEL of 5 ug/m(3) (and 1 ug/m(3)) primarily on grounds of infeasibility (Big River Zinc, Ex. 19-30; Cadmium Council, Ex. 19-43; Synpro, Ex. 19-46/Appendix I). The Council argued that a PEL of 5 ug/m(3) could not achieved by engineering and work practice controls in each of the primary cadmium producing industry segments represented by the Council.
Consequently, several commenters argued that OSHA should adopt a two-tiered approach to controlling worker exposure to airborne cadmium (Ex. L-140-28). The first tier would be a PEL, set at the level required by the health science data to protect workers' health. The PEL, in the case of industries where compliance by means of engineering and work practice controls was infeasible, could be achieved by any allowable (e.g., not worker rotation) combination of work practice and engineering controls and respirators. The second tier would be set above the PEL at the lowest feasible level that could be achieved by engineering and work practice controls.
OSHA, with some qualifications, agrees with industry's arguments in this regard and has responded by establishing separate engineering control air limits (SECALs) at the lowest feasible levels above the PEL for specified processes in particular industries. Employers in a particular industry covered by the SECAL will be obligated to achieve the SECAL by engineering and work practice controls to the extent feasible and to protect employees from exposures above the PEL by any mix of compliance methods, including engineering and work practice controls and respirators.
The establishment of a SECAL in this cadmium standard is similar to provisions in the asbestos standard [29 CFR 1910.1001 (f)(1)(ii); 1926.58 (g)(1)(ii)], requiring the employer to use engineering and work practice controls to attain the lowest achievable levels in specified processes and to supplement those controls with respirator use. In the asbestos standard, OSHA identified certain processes as ones in which it is not presumptively possible to attain the PEL through engineering and work practice controls (Building and Construction Trades Department, AFL-CIO v. Brock; 647 F.2d 1272 (D.C. Cir, 04/24/87). For these processes, OSHA set a higher PEL until such time as the lower PEL could be attained [29 CFR 1910.1001 (f)(1)(iii)] (See discussion under Section VIII - Regulatory Impact Analysis.) The Cadmium Council and its experts and witnesses also opposed a PEL of 5 ug/m(3) (and 1 ug/m(3)) on health grounds. They claimed that a PEL so low was not necessary to adequately protect workers. As discussed above in this preamble, OSHA rejects this argument.
A small number of health experts and others opposed a PEL of 5 as being too high to adequately protect workers from excess cadmium exposure (Public Citizen, Ex. 19-33; Massachusetts Organization of State Engineers and Scientists, Ex. 19-21). However, the Agency after careful analysis of the evidence in the record concluded that a PEL of 5 ug/m(3) is at or very near the limits of feasibility. Furthermore, the Agency concluded that a PEL of 5 ug/m(3), in conjunction with all the ancillary provisions of the standard, is sufficiently protective and that setting the PEL any lower would create additional health and safety problems. A more complete analysis of the feasibility issue can be found in the final Regulatory Impact Analysis section in this preamble.
Finally, in comments to the record (Duke Power, Ex. 19-18), OSHA was asked to clarify the allowable exposure where an employee is exposed to cadmium for more than 8 hours in any work day. The 8-hour time weighted average (TWA) for that day has to be reduced accordingly so that the employee is not exposed to greater amounts of cadmium by working more hours than he/she would have been by working eight hours. The reduction is made according to the following formula:
Maximum permissible limit (in ug/m(3)) = 40 divided by hours worked in the day.
Consequently, if the employee were to work 10 hours, the adjusted allowable exposure for this employee under the formula, 40 divided by 10, would be reduced to 4 ug/m(3). Though the employee may be exposed during part of the day to exposures above 5 ug/m(3), the PEL cannot be raised. No other formula is required for that adjustment. OSHA provides this explanation partly in response to a request from Duke Power Company (Ex. 19-18).
Exposure Monitoring: Paragraph (d).
This final standard imposes monitoring requirements pursuant to Section 6(b)(7) of the OSH Act (29 U.S.C. 655), which mandates that any standard promulgated under section 6(b) shall, where appropriate, "provide for monitoring or measuring of employee exposure at such locations and intervals, and in such manner as may be necessary for the protection of employees." To this end, as discussed below, OSHA has made several significant changes to the monitoring requirements included in the proposed cadmium rule.
The purposes served by requiring air sampling for employee exposures to cadmium include: determination of the extent of exposure at the worksite; prevention of employee overexposure; identification of the sources of exposure to cadmium; collection of exposure data so that the employer can select the proper control methods to be used; and evaluation of the effectiveness of selected controls. Monitoring further enables employers to notify employees of their exposure levels, as required by section 8(c)(3) of the Act.
Periodic monitoring provides the employer with assurance that employees are not experiencing higher exposures that may require the use of additional controls. In addition, periodic monitoring reminds employees and employers of the continued need to protect against the hazards associated with exposure to cadmium.
The collection of exposure monitoring data also enables an examining physician to be informed of the existence and extent of potential sources of occupational diseases.
The results of initial and periodic monitoring determine whether subsequent monitoring is necessary. Exposure monitoring is important not only to determine the level of cadmium to which employees are exposed and the frequency at which employees should be monitored, but also to determine whether other protective provisions of the standard need to be implemented. The employer's obligation to provide medical surveillance, for example, is triggered by monitoring results showing that an employee is exposed at or above the action level on 30 or more days per year (or 12 consecutive months). Other provisions of the standard typically are triggered by employee exposure levels above the PEL.
The exposure monitoring provisions in paragraph (d)(1) of this standard require the employer to determine the exposure of each employee exposed to cadmium. Samples must be taken within the employee's breathing zone (i.e., personal samples) and must reflect the employee's exposure, without regard to the use of respirators, to airborne concentrations of cadmium over an eight-hour period. A full description of "Breathing zone" is provided in the OSHA Instruction CPL 2-2.20B, CH-1, Nov. 13, 1990, Directory of Technical Support. Basically, it encompasses a sampling area as close as practical to the nose and mouth of the employee.
In certain circumstances, sampling each employee's exposure to cadmium may be required for initial monitoring. However, in many cases, the employer under paragraph (d)(1)(iii) may monitor selected employees to determine "representative employee exposures." Representative exposure sampling is permitted when there are a number of employees performing essentially the same job, with cadmium exposure of similar duration and level, under essentially the same conditions. In authorizing representative personal sampling for employees engaged in similar work, the standard requires that the member(s) of the exposed group reasonably expected to have the highest exposure shall be the one(s) monitored. This result is then attributed to the remaining employees of the group. At the very least in representative sampling, full-shift sampling must be conducted for each job function in each job classification, in each work area, and for each shift. At least one sample of the entire shift or consecutive representative samples over the length of the shift must be taken.
Although one commenter expressed opposition to the proposed requirement that sampling be conducted on each work shift (Tr. 7/18/90; 9-279), other commenters stated that the variation in exposure levels for the same job across shifts can be great (e.g., Tr. 7/17/90, pp. 41-217). Based upon its experience, OSHA agrees that such variation requires that sampling be conducted on each shift.
Initial monitoring of workplace exposures is required under paragraph (d)(2) of this standard for all employers who have a place of employment covered by this standard. The initial monitoring must be conducted as soon as possible and in any event no later than 60 days after the effective date of this standard. However, to eliminate unneeded monitoring, under conditions specified in paragraph (d)(2)(ii) of this standard, historic monitoring may be relied upon by the employer to satisfy the obligation to conduct initial monitoring. Thus, if an employer previously monitored an employee under exposure conditions closely resembling those currently prevailing and that monitoring satisfies all other requirements of this standard and was conducted within 12 months prior to the publication date of this standard, then the results of that monitoring can be used to satisfy the requirements for initial monitoring.
This constitutes a change from the cadmium proposal, where historic monitoring had to be conducted within 180 days of the publication date of this final standard to be usable in place of initial monitoring (55 FR 4121). Several industry commenters criticized the proposed limit of 180 days on the usability of historic monitoring data (Exs. 19-9 and 19-18). OSHA, in seeking to eliminate all unnecessary requirements and attendant costs from the final standard, felt that, so long as the strict conditions of paragraph (d)(2)(ii) were met, employee monitoring results obtained as long as 12 months prior to publication of this standard would be sufficiently reliable to make the requirement for initial monitoring of those employees unnecessary. However, OSHA does not feel comfortable accepting historic monitoring data from any era for these purposes, as some industry representatives have sought (Exs. 19-9 and 19-18). Indeed, the Agency believes that accepting historical data from periods greater than six months prior to the publication date of the standard is already somewhat incongruous since the minimum acceptable frequency for periodic monitoring required by the final standard is semi-annual. Furthermore, NIOSH and others have argued that even semi-annual monitoring is insufficient and have maintained that monitoring cadmium on a quarterly basis is good industrial hygiene practice (Tr. 7/17/90, p. 78; Exs. 8-62, 9-8, 57, 106).
OSHA recognizes these countervailing interests and concerns and seeks through a combination of requirements to achieve a balance that is both protective and efficient. In determining how to most efficiently protect employees, OSHA chooses to accept historic data from up to 12 months before promulgation of the standard, while requiring a minimum of semi-annual monitoring, supplemented by the two additional requirements for more frequent monitoring in paragraphs (d)(3)(i) and (d)(4).
The provision for use of "objective data" in paragraph (d)(2)(iii) of this standard is, except for the deletion of the reference to an EL (excursion limit), the same as in the proposal. The provision is discussed below in this summary and explanation in connection with paragraph (n)(2), where "objective data" is defined and the obligation to keep a record of it specified.
As suggested above, the requirements for monitoring frequency in paragraph (d)(3) of this standard also have been somewhat changed from those proposed. What remains the same are the following two basic rules. First, if the initial or periodic monitoring results (confirmed by another monitoring taken at least seven days later) show that employee exposures are below the action level, then under paragraph (d)(3)(ii) no further monitoring is required. OSHA estimates that most of the workers potentially exposed to cadmium are currently exposed to a geometric mean level below the AL of 2.5 ug/m(3)(see final RIA, e.g., Tables VIII-C43 and VIII-C44) and that these workers generally will be exposed below the AL. For these workers, OSHA expects that the employer will be required to comply only with the training provisions under paragraph (m) of the standard. Second, if initial or periodic monitoring results show employee exposures at or above the action level, then under paragraph (d)(3)(i) the employer must repeat monitoring for these individuals at least every six months.
What is different is that, unlike paragraph (d)(3)(i) of the proposal (55 FR 4121), there is no requirement in the final standard that the employer must monitor every three months (quarterly) employees whose monitoring results are above the PEL. The deletion of this specific requirement is partly in response to comments that the proposed monitoring requirements were too inflexible (American Iron and Steel Institute Tr. 7/18/90, p. 279). While opinions vary on the proper periodicity for monitoring, OSHA acknowledges the merit of more flexible monitoring for cadmium-related exposures (Ex. 106). Instead of the requirement for quarterly monitoring, OSHA in paragraph (d)(3)(i) of this final standard imposes a performance requirement on employers, requiring them to monitor with the frequency and pattern needed to assure that the following purposes of exposure monitoring be achieved: the monitoring results should reflect with reasonable accuracy the levels of exposure of employees and should assure the adequacy of respiratory selection and the effectiveness of engineering and work practice controls.
Depending upon exposure conditions, this performance criterion might require monitoring that is more or less frequent than the proposed quarterly monitoring. If, for example, exposure levels and patterns are well known and stable over time, monitoring as often as each quarter could well be redundant, in which case semi-annual monitoring probably would suffice. On the other hand, where exposure conditions change dramatically and more frequently than quarterly, more frequent monitoring probably would be required under paragraphs (d)(3)(i) as well as (d)(4).
Thus, the Agency has increased the flexibility of its monitoring requirements to give employers greater latitude to monitor according to the concrete conditions and industrial hygiene needs of their particular facilities. However, this flexibility is not without bounds. OSHA has supplemented it with the minimum requirement of semi-annual monitoring. Employers must monitor employees whose exposures are, or may be, at or above the action level at least semi-annually (55 FR 4121), assuring that these employees will be monitored at a reasonable interval (AISI, Tr. 7/18/90, p. 252). Requiring periodic monitoring at a stated frequency also facilitates enforcement by providing a clear compliance minimum.
The requirement for semi-annual monitoring at or above the action level was incorporated in the proposed cadmium standard (55 FR 4121) and has been incorporated into some OSHA health standards (Arsenic, 29 CFR 1910.1018; Lead, 26 CFR 1910.1025). The requirement for semi-annual monitoring above the PEL has been incorporated into other health standards (Benzene, 29 CFR 1910.1028). The requirement to monitor semi-annually employees exposed at or above the action level and/or the PEL is similar to the requirement in OSHA's standard for Formaldehyde (29 CFR 1910.1048). OSHA believes the monitoring schedule set forth in this final standard is necessary and sufficient.
In addition, whenever changes occur that may expose additional employees to cadmium at or above the action level or may expose employees already exposed at or above the action level to levels of cadmium above the PEL, additional monitoring is required under paragraph (d)(4). Such changes may occur in the production process, raw materials, equipment, personnel, work practices, or finished products. Whenever the employer has any reason to suspect that any other change might lead to such further exposure, then under paragraph (d)(4) the employer must resume monitoring. There is considerable support in the record for this requirement for additional monitoring (AISI Tr. 7/18/90, p. 280; Exs. 19-8; 19-21). OSHA considers this requirement necessary to protect employees from excessive exposures from changed circumstances.
OSHA recognizes that monitoring can be a time-consuming, expensive endeavor and therefore in paragraph (d)(3)(ii) of this standard allows employers to discontinue monitoring for employees whose sampling results indicate exposures are below the action level. It is hoped that this will provide incentive to employers to control their employees' exposures to cadmium to below the action level, thus maximizing the protection of employees' health.
Since OSHA has eliminated the proposed requirement that employers comply with an EL from this final standard, all of the proposed requirements for monitoring and notification of employees relating to an EL have likewise been eliminated.
The standard in paragraph (d)(5) further requires that employers notify each of their employees individually of the results of monitoring that reflects their exposure. Notification is to be given in writing. In addition, employers must post monitoring results in an appropriate location accessible to all affected employees.
Several employers opposed parts or all of these notification requirements in the cadmium proposal. Duke Power, for example, opposes posting results as a violation of employee privacy and as potentially alarming and instead favors providing notice at crew meetings when questions can be answered (Ex. 19-18). OSHA does not believe an employee has a privacy interest in the air cadmium levels to which he/she is exposed. In addition, OSHA sees no reason or evidence in the record that posting sampling results is likely to alarm employees any more than individual written notification or notice given at crew meetings.
By contrast, McDonnell Douglas generally supports the proposed written notification provision but favors posting over individual written notification because it is more efficient (Ex. 19-22). AISI feels the requirements for individual notification and posting are "duplicative and unnecessarily burdensome" (Tr. 7/18/90, p. 280). The requirement for individual written notification, AISI says, will "dramatically increase cost without a commensurate advantage to the employee" (Tr. 7/18/90, p. 281). AISI suggests that OSHA allow the employer to choose between these two methods of notification (Tr. 7/18/90, p. 280).
In other health standards, OSHA typically has required written notification of employees either individually or by posting (Ethylene Oxide 29 CFR 1910.107; Formaldehyde 29 CFR 1910.1048; or Lead, 29 CFR 1910.1025). The additional requirement to do both was incorporated into the proposal (55 FR 4122). No evidence was submitted to the record that posting of results is costly or inefficient. The issue is whether the notification is redundant (Tr. 7/18/90; p. 252). OSHA added this requirement in the proposal because the Agency believes that the two forms of notification enhance and complement each other to the benefit of the employee. Posting enhances the collective knowledge in the workplace of employee exposures, which in turn enhances each employee's understanding of his/her own exposure. Thus, each notification requirement performs a different function. Individual, written notice assures that each employee is notified. Posting the results facilitates other employees, their designated representatives, supervisors, and employers as well in becoming aware of exposure levels within the workplace.
The employer is obligated to provide written notice and post results within 15 working days after receipt of the results. Whenever the PEL is exceeded, the written notification must contain a statement that the PEL has been exceeded and a description of the corrective action(s) being taken by the employer to reduce the employee's exposure to or below the PEL. This requirement to inform employees is in accordance with section 8(c)(3) of the Act and is necessary to assure that employees are informed whenever the PEL is being exceeded and to assure employees that the employer is making efforts to furnish them with a safe and healthful work environment.
In order to obtain accurate exposure monitoring results, the employer under paragraph (d)(6) is required to use monitoring and analytical methods that have an accuracy, at a confidence level of 95%, of not less than plus or minus 25% for airborne concentrations of cadmium at all the relevant levels (i.e., levels between the action level (AL), the PEL, and, where relevant, the SECAL). The main reason OSHA is requiring this degree of accuracy for air monitoring results is to ensure that air monitoring results are sufficiently accurate across the relevant range of exposure levels. Accuracy of measurements is critical since monitoring results serve a number of important functions in the cadmium standard. For example, certain central requirements of the standard, like medical surveillance, engineering controls, and respirator use, are triggered by employee exposures exceeding particular levels like the AL or the PEL. In addition, the medical removal provision requires that a removed employee not be placed in a job where exposure levels are at or above the AL.
Although not a requirement of the standard under paragraph (d), OSHA expects that all laboratory analyses of air sampling data will be performed in laboratories with demonstrated proficiency for measuring cadmium in air at these levels.
The accuracy requirements in paragraph (d)(6) are basically the same as the proposal (55 FR 4121) and are similar to the precision and accuracy requirements in other OSHA health standards (e.g., Lead, 29 CFR 1910.1025; Benzene, 29 CFR 1910.1028). By defining the precision and accuracy requirements for samples used to determine the TWA airborne concentration of cadmium in the workplace, OSHA ensures that the method of monitoring and analysis is adequate whether single or multiple samples are taken. While some may argue that such a stringent requirement for accuracy is unwarranted or unobtainable, (Exs. 19-14; 19-18) OSHA is of the opinion that, given the current state-of-knowledge among laboratories in which analyses for heavy metals are routinely performed, it is not unreasonable to require such accuracy. Recent NIOSH Proficiency Analytical Testing (PAT) rounds have included samples containing cadmium as low as 6 ug with a performance limit of + or - 0.8 ug. The analytical range for cadmium in the PAT samples is 2 to 20 ug. Inclusion of this requirement will provide incentive for other laboratories to improve their accuracy over time. In addition, with the TWA PEL set at 5 ug/m(3), the higher of the two PELs included in the proposal (55 FR 4052), and with the deletion of the excursion limit, the comments suggesting that current methods and laboratories are unable to achieve such accuracy are no longer relevant. The OSHA method ID-189, listed in Appendix E, provides analytical precision and accuracy capability for a standard that is five times lower than the final standard. By using this method, and currently available instrumentation, analytical laboratories can perform a sample analysis that meets the required level of both precision and accuracy of paragraph (d)(6).
The employer is also required under paragraph (o) of this standard to allow employees or their designated representatives an opportunity to observe employee exposure monitoring. This provision is required by Section 8(c)(3) of the Act [29 U.S.C. 657(c)(3)].
Several commenters indicated that OSHA had erred in its proposal regarding appropriate sampling devices for cadmium. Mr. G. F. Stone, Manager of Occupational Health and Safety for the Tennessee Valley Authority, submitted that in section VIII (E) of the proposal, the Agency referred to passive dosimeters and charcoal tubes as monitoring devices for cadmium. Mr. Stone correctly indicated that this reference should be deleted because such sampling devices can only be used for vapors (Ex.19-5). It has been deleted.
Regulated Areas: Paragraph (e):
This final standard contains requirements that regulated areas be established whenever and wherever an employee's exposure to airborne concentrations of cadmium is, or can reasonably be expected to be, above the PEL. Access to these areas is to be controlled and limited to authorized persons. In accordance with performance criteria, regulated areas are to be demarcated in any manner that adequately alerts employees of the boundaries of these areas. No detailed specifications are required for demarcating regulated areas.
The requirement to establish regulated areas extends to temporary and to intermittent exposures above the PEL, as well as to more constant ones. Thus, for example, whenever it is reasonably expected that the PEL may be exceeded for an employee performing a maintenance operation, a regulated area shall be established for the area and for the length of time required to perform that operation and for any additional time that air cadmium levels may be expected to continue to exceed the PEL. For this cadmium standard, the existence of a hazard, and not the particular type of operation or work being performed, is the basis for determining the need for protective measures.
Access to the regulated area is restricted to "authorized persons". For purposes of this standard, these are persons who are authorized by the employer to be present in the area, generally because of their job duties, and persons authorized by the OSH Act or OSHA regulations to be in that area.
Areas where employee exposures are over the PEL need to be demarcated to warn employees who are not essential to the performance of tasks within the area to keep out. Demarcation is also necessary to warn employees required to be in the regulated area that respirators must be worn to avoid excessive exposures via inhalation and that good personal hygiene must be practiced to avoid exposures to cadmium via ingestion. Good personal hygiene practices include refraining from smoking, eating, drinking, chewing tobacco or gum, refraining from applying cosmetics in regulated areas, and refraining from carrying the products associated with these activities into regulated areas or storing such products there.
OSHA received specific comments from medical experts that employees should not carry food, tobacco products, gum, or such other products into cadmium contaminated areas since these products rapidly become contaminated themselves (Ex. 29). Consumption of heavily contaminated products contributes to cadmium accumulation in the human body. (ref. in Kjellstrom, Ex. 29). Other hygienic practices associated with working in regulated areas also are required under paragraph (j) of this standard, which is discussed below.
The purpose of a regulated area is to assure that employers make employees aware of the presence and location of cadmium at levels above the PEL in the workplace. This minimizes the number of employees excessively exposed. The employer makes employees aware of this potential hazard by demarcating the area and posting warning signs. Since under paragraph (m)(1) of this standard the signs must state that only authorized personnel are allowed in the area and that respirators must be worn in the area, the signs and the demarcation of such areas should effectively warn employees not to enter these areas unless they are authorized to do so and only if they are wearing a respirator.
In this way, employees who work in other areas of the workplace will not be unnecessarily exposed to cadmium if they are required by their job to work in a regulated area for part of the workday. Due to the serious nature of the adverse health effects associated with excess exposure to cadmium, no one should be in a regulated area without proper personal protection.
This provision will reduce the overall cadmium exposure of many employees, thereby reducing their risks of contracting cadmium-induced illness. OSHA considers this to be necessary to further reduce the any remaining risk of disease at the PEL where risk is estimated without regard to the additional reductions in risk attributable to this requirement for regulated areas and to the other ancillary requirements.
The establishment of regulated areas is an effective means of limiting excess cadmium exposure to as few employees as possible. This is consistent with good industrial hygiene practice whenever exposure to a toxic substance can cause serious health effects. The requirement provides additional benefits to employers in that, by limiting access to regulated areas to authorized persons, the employer's obligation to implement other provisions of this standard for employees who are exposed above the PEL is limited to as few employees as possible.
Readily observable temporary sign(s) posted at the boundary of the area, which are consistent with the Hazard Communication Standard, will be sufficient to remind employees that respirators and good personal hygiene practices are needed and that unprotected people should not enter the area.
With two exceptions, these requirements for regulated areas are essentially the same as those proposed. One exception relates to the proposed EL. With the deletion of the proposed EL from this final standard, discussed above in the section explaining the PEL, all references to an EL also have been eliminated from the requirements for, and discussion of regulated areas.
The other exception relates to how to measure the exposure level that determines whether a regulated area should be established. The language of the proposal, that a regulated area shall be established "wherever airborne concentrations of cadmium are, or can reasonably be expected to be in excess of the permissible exposure limit...", might be considered ambiguous. It might be interpreted to mean that, regardless of employee exposure levels, a regulated area shall be set up wherever area sampling shows concentrations of cadmium to exceed the PEL. That was not OSHA's intention. In fact, OSHA does not prescribe or rely upon area sampling in determining compliance with the PEL. The language of this final standard clarifies OSHA's intention to require the employer to establish a regulated area only where an employee is or can reasonably be expected to be exposed to airborne concentrations of cadmium in excess of the PEL based on breathing zone samples.
Methods of Compliance: Paragraph (f)
With regard to methods of compliance, the final standard follows the proposal in its fundamentals except in three major ways. First, where the employer demonstrates that exposures are only intermittent, a 30-day exclusion is applied to the requirement to implement engineering controls to achieve the PEL. Second, for a small number of industries where it is not feasible to achieve the PEL by engineering and work practice controls, separate engineering (and work practice) control air limits (SECALs) of 15 ug/m(3)and/or 50 ug/m(3)are established at the lowest levels feasible above the PEL. (See Table F-I.) And third, OSHA in this final standard has set out in general terms the necessary elements of a compliance program.
Beginning with the fundamentals, paragraph (f)(1)(i) of this standard, like the proposal, requires employers to institute engineering and work practice controls as the primary means to reduce and maintain employee exposures to cadmium to levels at or below the PEL. Engineering controls include the installation of equipment, such as forced air ventilation, or the modification of a process, such as enclosing it, to control employee exposure levels. Work practice controls involve the manner in which a task is performed, such as how the worker positions himself/herself relative to the source of exposure and/or to the engineering controls, to control employee exposure levels.
Under paragraphs (f)(1)(i), (ii), and (iv) the employer is required to implement engineering and work practice controls even if feasible engineering and work practice controls are inadequate to lower exposures to or below the PEL or, where applicable, the SECAL. In such circumstances, the employer must implement engineering and work practice controls to reduce employee exposures to the extent possible and must provide supplemental respiratory protection in accordance with paragraph (g) to comply with the PEL.
Primary reliance on engineering controls and work practices is consistent with good industrial hygiene practice (NIOSH, Tr. 7/17/90, pp. 51-56; Exs. 57; 77; 19-8; 19-21). The Agency also relies on traditional adherence to a hierarchy of controls that prefers engineering and work practice controls over dependence upon respirators. Such reliance also is supported by some employers and company doctors (Exs. 19-31; L-19-57; 118; 19-2).
Engineering controls are preferred by OSHA for a number of reasons. Engineering controls are reliable, provide consistent levels of protection to large numbers of workers, can be monitored continually and inexpensively, allow for predictable performance levels, and can remove toxic substances from the workplace. Once removed, the toxic substances no longer pose a threat to the employee. Moreover, the effectiveness of engineering controls does not depend to any marked degree on human behavior, and the operation of equipment is not as vulnerable to human error as is the use of personal protective equipment.
Engineering controls can be grouped into 3 main categories: (1) substitution, (2) containment and isolation, and (3) ventilation, both general and localized. Quite often a combination of these controls can be applied to an industrial hygiene problem to achieve satisfactory air quality. However, it may not be necessary or appropriate to apply all these measures to any specific potential hazard.
Substitution can be the appropriate solution to an industrial hygiene problem. One of the best ways to prevent workers from being exposed to a toxic substance is to stop using it entirely. Although substitution is not always possible, one should always consider whether a non-toxic or less toxic material could be substituted for a more toxic one. OSHA received comments on the availability of cadmium substitutes for several industry segments (Ex. 8-706). Another kind of substitution that may provide effective control of an air contaminant is exchanging one type of process equipment for another, or in some cases, exchanging one process for another. For example, a process change in chemical production from powder to pellets or granules will usually reduce exposures. Similarly, automation of a process can further reduce the potential hazard to an employee.
In addition to substitution, there are two basic ways to effectively control employee exposure levels by separating workers from the source of the hazard. In one, containment (enclosure), the hazard is enclosed by a physical barrier, which contains it at its source, thereby separating the hazard from most workers. In the other, isolation, the hazard is not contained but the workers are isolated from the source of the hazard. Isolation can be accomplished, for example, by placing the employees in a clean room, in a properly ventilated cab, or at some distance from the source of the exposure.
Frequently containment maximizes the effectiveness of other engineering controls such as local exhaust ventilation. For example, where a chemical mixing operation is enclosed in a room, confining the airborne contaminants generated by the operation to a small area, the application of local ventilation to control the contaminant at the source is more effective.
Ventilation, general or local, is the most important engineering control available to the industrial hygienist. (See discussion below on mechanical ventilation.) Its principal application is to maintain airborne concentrations of contaminants at acceptable levels in the workplace. A local exhaust system is used to capture an air contaminant at or near its source and to carry it off before it spreads throughout the workplace. General ventilation, on the other hand, allows the contaminant to spread throughout the workroom but dilutes its concentration by circulating large quantities of air into and out from the workroom. A local exhaust system is generally preferred to ventilation-by-dilution (general ventilation) because it provides a cleaner and healthier work environment. Also, a local exhaust system requires a relatively small volume of air and uses a smaller fan and dust collector.
Work practices, as distinguished from engineering controls, involve the way a task is performed. The Agency has found that good work practices can be a vital aid in achieving compliance with the PEL. Some fundamental and easily implemented work practices are: (1) following the proper procedures to minimize exposures in operating production and control equipment; (2) not eating, drinking, smoking, chewing tobacco or gum, or applying cosmetics in regulated areas or carrying products associated with these activities into regulated areas; and (3) good housekeeping.
Good housekeeping plays a key role in the control of occupational health hazards. Accumulations of cadmium dust increase the risk that workers' exposures will rise above the PEL or the AL. Dust in the workplace on overhead ledges, equipment, floors, etc., should be removed before some disruption, like traffic or random air currents, re-entrains the dust and makes it airborne again. A regular cleanup schedule using HEPA filtered vacuum cleaners is an effective method of removing cadmium dust from the work area. Similarly, immediate cleanup of any toxic spills is a very important work practice control measure.
Periodic inspection and maintenance of process equipment and control equipment, such as ventilation systems, is another important work practice control. In plants where total containment is used as an engineering control, the failure of the ventilation system for the containment area can result in hazardous exposures in the enclosure. Frequently, equipment which is near failure or in disrepair will not perform normally. Regular inspections can detect abnormal conditions so that timely maintenance can then be performed. If equipment is routinely inspected, maintained, and repaired, or replaced before failure is likely, there is less chance that hazardous exposures will occur.
In addition to the above work practice controls, workers must know the proper way to perform their job tasks to maximize the effectiveness of engineering controls. For example, if a worker inappropriately performs a task away from an exhaust hood, the control measure will be of no use. Failure to properly operate engineering controls may also contaminate the work area. Workers can be alerted to safe operating procedures through fact sheets, discussions at safety meetings, and other educational means.
Good supervision is another important work practice. It provides needed support for assuring that proper work practices are followed by workers. By directing a worker to position the exhaust hood properly or to improve work practices, such as weighing toxic materials or handling contaminated scoops or shovels, a supervisor can do much to minimize unnecessary exposure to air contaminants.
Employees' exposures also can be controlled by scheduling production and/or workers' tasks in ways that minimize employee exposure levels. For example, the employer can schedule operations with the highest exposures at a time when the fewest employees are present. Thus, clean-up operations in which toxic substances are involved might be performed at night or other times when the production staff is not present. Such methods of controlling worker exposures to contaminants are known as administrative controls. OSHA generally approves of the use of administrative controls. However, the Agency prohibits using one form of administrative control, worker rotation, as a method of compliance with this standard. Worker rotation circulates employees into and out of contaminated areas, thereby reducing the exposure to individual employees by increasing the number of employees exposed. Since even low cadmium exposure levels are associated with cancer and kidney damage, OSHA prohibits worker rotation, because it places more employees at risk of material impairment to their health (Ex. 19-57; Tr. 7/18/90 p. 252). For these reasons, OSHA finds comments to the contrary unpersuasive (Ex. L-19-57; Tr. 7/18/90, pp. 252-322).
Respirators are another, important method of compliance. However, to be used effectively, respirators must be individually selected; fitted and periodically refitted; conscientiously and properly worn; regularly maintained; and replaced as necessary. In many workplaces, these preconditions for effective respirator use are difficult to achieve with sufficient consistency to provide adequate protection. The absence of any of these preconditions can reduce or eliminate the protection the respirator provides to the employee.
Because there are so many ways that respirators can be rendered ineffective and so many potential problems associated with their use, OSHA has traditionally relied less on respirators than on engineering and work practice controls in the hierarchy of controls. For example, where work is strenuous, the increased breathing resistance of certain types of respirators may contribute to an employee's health problems and may reduce the acceptability of wearing a respirator to employees. Although experience in industry shows that most healthy workers do not have physiological problems wearing properly chosen and fitted respirators, common health problems can cause difficulty in breathing while an employee is wearing a respirator.
Employees with respiratory system and cardiac diseases may have difficulties in wearing respirators. Cardiac or cardiorespiratory diseases that may affect respirator use include coronary thrombosis, any type of congestive heart disease, other ischemic heart diseases, and hypertension.
The amount of difficulty associated with respirator use will clearly depend both on the degree of cardiorespiratory inadequacy and on the amount of physical effort required by the work. Some people who may have difficulty wearing a negative pressure respirator, which increases the resistance to inspiration, should be able to manage well with a positive pressure type respirator.
The decision about the fitness of the individual to wear a respirator is a judgment that can best be made by a licensed physician, who must take into account the state of the individual's health as well as the physical requirements of the job (Bond; Tr. 7/18/90, pp. 199-200). Consequently, OSHA requires medical examinations under paragraph (l)(6) of this standard that target the main potential health problems for workers required by paragraph (g) to wear respirators. For any employee required by his/her job to wear a respirator who has not had a medical examination within the preceding 12 months to evaluate the employee's physical fitness to wear a respirator, such a medical examination is required prior to assignment to that job.
Safety problems created by respirators that limit vision and communication must always be considered. In some difficult and dangerous jobs, effective vision or communication is vital. Voice transmission through a respirator can be difficult, annoying, and fatiguing. In addition, movement of the jaw in speaking can cause leakage, thereby reducing the efficiency of the respirator and decreasing the protection afforded the employee. Also skin irritation can result from wearing a respirator in hot, humid conditions. Such irritation can cause considerable distress to workers and can cause workers to refrain from wearing the respirator, thereby rendering it ineffective. For all these reasons, OSHA has concluded once again that reliance upon respirators as the primary method to reduce a workers exposures should be minimized. This decision is consistent with the cadmium proposal and is based upon OSHA's experience and generally accepted principles of industrial hygiene. There is no evidence or data in the record that would justify OSHA changing its long-established position on this matter.
Respirator efficiency ultimately relies on the individual employee's good work practices, and respirator programs place the burden of protection on the employee. By contrast, engineering controls entail relatively high, front-end costs, but have the advantage that they can control toxic substances before employees are exposed to them. In any event engineering controls do not rely for their effectiveness so routinely on the individual employee's good habits. To date, therefore, OSHA is satisfied that respirators do not offer equal or better protection than engineering controls.
Because respirators are less reliable than engineering and work practice controls and may create additional problems, they are not the preferred method of compliance with the PEL. Accordingly, their use as a primary control is restricted to certain circumstances by paragraph (g)(1) of this standard. In those circumstances, where engineering and work practice controls cannot be used to achieve the PEL (e.g., certain maintenance and repair operations, emergencies, wherever an employee is exposed above the PEL in an industry to which a SECAL is applicable, or during periods when equipment is being installed), OSHA recognizes that respirators may be essential to reduce worker exposure, and provision is made in paragraph (g) for their use as primary controls. In other circumstances, where work practices and engineering controls alone cannot reduce exposure levels to the PEL, respirators also may be used for supplemental protection. In these situations, the burden of proof of infeasibility is appropriately placed on the employer.
Respirators also may be used when an employee exposed at or above the action level requests a respirator. In such cases, it is OSHA's intention that the employer comply with all provisions of the standard applicable to required respirator use; e.g. medical examinations under paragraph (l)(6) and other provisions in paragraph (g).
In all these ways, this final standard basically tracks the proposal in its approach to, and requirements for, methods of compliance. However, three significant changes have been made to the proposed standard in this regard.
(1) For a small number of processes in selected industries where it is not feasible to achieve the PEL by engineering and work practice controls alone, separate engineering (and work practice) control air limits (SECALs) of 15 and/or 50 ug/m(3) have been established as the lowest feasible levels above the PEL by paragraph (f)(1)(ii) of this standard (See paragraph (f)(1)(ii) and Table 1 in the standard and also see Section VIII - Regulatory Impact Assessment, in this preamble for those industries to which a SECAL is applicable). The result is that employers in these industries are not required to achieve the PEL exclusively by engineering and work practice controls but are instead only required to comply with the PEL by any combination of methods of compliance, including respirators, and to comply with the higher SECAL exclusively by means of engineering and work practice controls. Like the PEL for all other industries and occupations, the SECAL, where applicable, must be achieved by engineering and work practice controls, except to the extent that the employer can demonstrate that such controls are not feasible.
(2) A 30 day exclusion for intermittent exposure has been added to the general requirement in paragraphs (f)(1)(i) and (i) of this standard that the PEL and the SECAL must be achieved by engineering and work practice controls. Under the exclusion, the employer's obligation to implement engineering and work practice controls to comply with the PEL or the SECAL is not triggered if an employee is exposed only intermittently so long as the employee is not exposed above the PEL (SECAL) on 30 or more days during a year (12 consecutive months). Thus, if an employee is exposed to cadmium on only 29 days during a year, even if the exposure is above the PEL (SECAL) on all of these days, the employer is not required by this standard to implement engineering and work practice controls to control exposures to the PEL (SECAL). The burden is on the employer to prove the required elements of the exclusion from the obligation to achieve the PEL or, where relevant, the SECAL by engineering and work practice controls.
(3) In paragraph (f)(2)(ii), OSHA has set out in general terms the necessary elements of a compliance program. Similar elements were included in OSHA"s health standards for arsenic (29 CFR 1910.1018).
OSHA discusses these changes in order. First, OSHA has decided to adopt a separate engineering (and work practice) control air limit (SECAL) above and in addition to the PEL for a number of reasons, some quite general and others specific to conditions in the cadmium industries and occupations. The main reason OSHA has adopted this two-tier structure, which was repeatedly urged upon OSHA by the Cadmium Council (Ex. L-140-28), is that it is simultaneously more protective of workers' health and feasible.
Based upon the evidence in the record (Health Effects; QRA), the PEL for cadmium must be set at least as low as 5 ug/m(3). By implementing the new PEL in conjunction with the ancillary provisions of the standard, OSHA expects that cadmium exposed workers will be protected from significant risks of kidney damage and lung cancer (Ex. L-140-50; See Section VI - Quantitative Risk Assessment). In addition, (See Section VIII - Regulatory Impact Analysis), a PEL of 5 ug/m(3) is at or very near the limit that can be achieved by engineering and work practice controls for thousands of cadmium exposed employees. Consequently, the health science data requires OSHA to set the PEL at 5 ug/m(3), and the economic and technological data indicate that level is generally within the limits of feasibility.
However, for a relatively small minority of cadmium exposed workers, concentrated almost exclusively in easily identifiable and distinct industry segments,like the primary cadmium producing industries of cadmium refining and zinc smelting, Ni-Cd battery manufacturing, lead smelting, plastic stabilizer production, plating and cadmium pigment production, a PEL of 5 ug/m(3) does not appear to be achievable by engineering and work practice controls in a number of processes. (See Table 1 and discussion under Section VIII - Regulatory Impact Assessment.) Under these circumstances, and focusing exclusively for the moment on policy issues, OSHA is faced with a choice. OSHA can set the PEL high enough that it can be achieved by engineering and work practice controls in most of the operations most of the time (United Steelworkers of America v. Marshall, 647 F.2d 1139, at 1272 [D.C.Dir. 1980], cert. denied, 453 U.S. 913 ) in all or nearly all of the industries and in all of the occupations. But in that case, the relatively severe feasibility constraints in the primary cadmium producing industries might act as the limiting factor for protecting all cadmium exposed employees, and the vast majority of cadmium exposed workers outside these industries would be less protected than they can and need to be. For most cadmium exposed workers, a PEL of 5 ug/m(3) is feasible by engineering and work practice controls alone and would provide greater protection. Moreover, even for employees in industries that cannot control air cadmium levels to 5 ug/m(3), setting the PEL at a level no lower than the lowest level that can be achieved by engineering and work practice controls also would be less protective.
In general, setting the PEL at the lowest level achievable by engineering and work practice controls in cases where the health science data shows significant remaining risk at that level means that workers may not be adequately protected. Employers in those cases would not be required, as they would be if the PEL were set at the lower level indicated by the health science data, to provide additional, needed protection to workers through respirators and compliance with other provisions.
Although, as was stated above, the Agency does not believe that respirators are as effective or as safe as engineering controls in protecting workers, OSHA has no doubt that respirators are eminently better than no protection at all. Furthermore, although OSHA is reluctant to require workers to wear respirators routinely for extended periods of time, where the health science data indicate that additional worker protection is required below the level attainable by engineering and work practice controls, OSHA believes, on balance, that it is important to assure that additional protection be provided, even if this necessitates reliance upon routine use of respirators.
To the extent that OSHA in this standard is divorcing the PEL from the SECAL and is setting the PEL at the lower level indicated by the health science data, OSHA is establishing a protective policy. Some precedent for this may be found in the way OSHA responded to the recent non-ferrous foundry industry lead remand (55 FR 3146, Jan. 30, 1990).
However, the issues in the lead remand case were presented in such a different context that OSHA did not have the opportunity or the need to broadly reconsider the relationship between the health data and the PEL, on the one hand, and the feasibility data and the engineering control limit, on the other. In the lead remand, the PEL had been established more than a decade before. In that context, the only question for OSHA on remand was whether that PEL was feasible in particular remand industries and, if not, what was the lowest feasible PEL industry by industry.
By contrast, in this standard, OSHA is consciously deciding to set the PEL lower than the level achievable by engineering and work practice controls in a number of processes in the primary cadmium producing industries. OSHA is aware that there are arguments for and against this decision, and indeed this is the first time the Agency has decided so clearly to separate the PEL from the SECAL. After extensive consideration of the pros and cons, OSHA has decided that the added protection to cadmium exposed workers resulting from this decision outweighs the attendant disadvantages deriving from the need in certain industries with a relatively small number of exposed employees for greater reliance on respirators to supplement engineering and work practice controls.
OSHA believes this to be good policy, which is supported, and may under certain circumstances even be required, by law. Under section 6(b)(5) of the OSH Act the Agency is legally required to set standards that "to the extent feasible" best protect workers from significant risks of material impairment of health. As stated in the cadmium proposal (55 FR 4094), OSHA does not believe that this obligation can be satisfied by using a lowest-common denominator approach to protecting workers, i.e., by protecting all workers only to the extent that the most severe feasibility constraint on protecting any worker would allow. On the contrary, OSHA believes that if a minority of workers cannot be as effectively protected as the majority, that fact is not an adequate reason to forego protecting the majority to the extent feasible. The courts seem to agree.
In the recent decision involving OSHA's asbestos standard, the U.S. Court of Appeals for the District of Columbia Circuit appears to have held that, where there is continuing significant risk at a PEL of 0.2 fibers per cubic centimeter and a PEL of 0.1 fibers per cubic centimeter is achievable in an industry sector employing 93% of the exposed workers, then, absent some persuasive justification to the contrary, OSHA cannot legally impose the higher PEL on that sector even if the lower PEL could not be achieved in operations in other industry sectors. The court, therefore, remanded the case to OSHA "to address the issue of disaggregating the general industry standard to afford workers the benefits of more stringent standards in areas where they are feasible." Building and Construction Trades Dept., AFL-CIO vs. Brock, 838 F.2d 1258, 1272-73. OSHA considers its decision in this rulemaking to require compliance with a SECAL and a PEL in certain industries to be in accordance with the asbestos opinion.
With regard to the second significant change in the proposed cadmium standard, OSHA in paragraph (f)(1)(iii) of this final standard has added an exclusion to the general requirement of paragraphs (f)(1)(i) and (ii) that the PEL and the SECAL must be achieved by engineering and work practice controls. The exclusion is for employees who are only intermittently exposed to cadmium and are exposed above the PEL on fewer than 30 days per year (12 consecutive months). OSHA received comments on the need for such an exclusion (e.g., EEI, Tr. 7/19/90, pp. 5-68).
OSHA is aware that this introduces an added element of complexity to the standard. However, the Agency believes the exclusion is one method of providing needed flexibility, in a standard that applies to multifarious industries and occupations, while protecting workers.
Under the exclusion, the employer's obligation to implement engineering and work practice controls to comply with the PEL or the SECAL is not triggered until an employee is exposed above the PEL on 30 or more working days during a year. Where the exposure is for fewer than 30 working days, the employer may use any mix of controls to achieve the PEL, including respirators. However, OSHA has qualified the exclusion by requiring the employer to demonstrate that the employee is only intermittently exposed. OSHA considered several options when reviewing the request for an exclusion to engineering controls. (See also Ex. L-144-28) OSHA decided to add an exclusion to the final standard for several reasons. First, under current exposure conditions, the main threat from exposure to cadmium is cumulative. Thus, assuming stable exposure levels, the fewer the days the worker is exposed, the less cadmium will accumulate in the worker's body. At some point, the risk of adverse health effects from so few days of exposure per year is reduced to insignificance. Consequently, some exclusion is justified.
Second, in a number of the cadmium using industries (e.g., plastics manufacturers who use cadmium stabilizers), as distinguished from the cadmium producing industries, exposure to cadmium is typically intermittent and brief (e.g., Exs. 120; 8-716). Under such conditions of exposure, it may not be economically feasible, cost effective, or very beneficial to workers' health for employers to invest the monies needed to install engineering controls to control cadmium to the PEL.
Third, with regard to industries and occupations that are neither primary producers of cadmium nor routine users of cadmium, the 30-day exclusion broadly means that engineering and work practice controls need not be implemented and consequently that in this respect the standard is feasible.
The alternative to incorporating an exclusion in the requirement to implement engineering controls would require employers to implement engineering controls wherever employees are exposed to cadmium above the PEL, even if they are only exposed on one or several days a year. OSHA does not think that the expense for implementing engineering controls in such circumstances, which can be quite high, would be justified. Consequently, incorporating some sort of exclusion seems to make sense in controlling occupational exposure to cadmium.
The question, then, is what number of days should be selected as the maximum, above which engineering and work practice controls must be implemented. There is no simple, scientifically definitive answer to that question. OSHA chose fewer than 30 working days per year in part because the lead standard incorporated a similar exclusion and in part to make this exclusion congruent with the exclusion provided in paragraph (l)(1)(i) regarding medical surveillance. Since lead and cadmium are both heavy metals that accumulate in the body, it seemed appropriate to incorporate similar maxima as triggers. Furthermore, industry representatives indicated that 30 working days per year appeared to reasonably reflect the frequency patterns for intermittent exposures in their industries (Tr. 7/19/92, pp. 10-15). In any event, OSHA is assured that no number of days other than 30 per year would be more reasonable.
In providing this exclusion, OSHA wants to make clear its intention to provide relief exclusively to employers whose employees are exposed to cadmium only intermittently and otherwise are effectively not exposed to cadmium at all. If employees are only exposed to cadmium on fewer than 30 working days, with respirator use required to reduce exposures that are above the PEL, the cumulative exposure allowed under the exclusion is expected to be minimal. On the other hand, if employees are exposed to cadmium above the PEL on fewer than 30 working days, but also are exposed at or below the PEL on many, most, or all other days, then such an exclusion might allow employees to experience much higher cumulative exposures over a 12-month period, well above what would otherwise be considered acceptable exposure levels. That is not OSHA's intention. Consequently, the 30-day exclusion does not apply to employees who have more than nominal exposure to cadmium in addition to the exposure during the fewer than 30 days. Where the employee has such other exposure, regardless of whether the employee is exposed above the PEL on fewer than 30 days a year, the employer is obligated, to the extent feasible, to achieve the PEL or the SECAL, whichever is relevant, by means of engineering and work practice controls. The Agency hopes this 30-working-day exclusion will make the standard more flexible in the great variety of intermittent exposure conditions to which the standard will apply.
Under paragraph (f)(1)(iii), it is the employer's responsibility to demonstrate the existence of all the elements required for the employer to be able to take advantage of the exclusion. Thus, the employer must prove that: (a) the employee is exposed above the PEL on fewer than 30 days per year; and (b) the employee is effectively not otherwise exposed to cadmium. OSHA placed the burden of proof on the employer for several reasons. First, the employer is in the best position to demonstrate the existence of all the elements, because the employer has the best access to needed information about employee exposure levels and, where existing information is inadequate, the employer also is in the best position to develop the necessary information. The employer is best able to gather, develop, correlate and maintain the exposure data needed to assess an employee's exposure to cadmium. The employer, for example, can best determine how often to monitor a particular employee to satisfy the burden of proof for the exclusion. Second, by contrast, since OSHA generally only inspects individual workplaces periodically and relatively briefly, it would be extremely difficult for OSHA to develop or gather the information concerning the intermittency and intensity of employee exposures needed to determine whether the exclusion applies. Third, the employer has an interest in demonstrating the applicability of the exclusion to his/her employee(s). Employers generally believe that engineering controls are more expensive than other methods of compliance and therefore have a perceived economic incentive to assure that engineering controls are not implemented for any employee for whom this standard does not require them.
(3) The third significant change to the proposal is the requirement for specific elements in the written compliance program. As modified, paragraph (f)(2) requires an employer who has employees exposed over the PEL to establish and implement a written compliance plan which describes the methods to be used to reduce employee exposure within his/her workplace to or below the PEL. The 30-day exclusion in paragraphs (f)(1)(i) and (ii) does not apply to the requirement to develop a written compliance plan, because, regardless of the manner in which exposure must be controlled, a plan must be developed to show how it will be achieved. The plan must provide for compliance through engineering and work practice controls, where required by the standard, to the extent feasible. These written plans must be furnished upon request for examination and copying to representatives of the Assistant Secretary, representatives of the Director of NIOSH, and affected employees or their representatives; and must be reviewed and updated, as discussed elsewhere in this preamble.
The purpose of requiring an employer to establish a written compliance program and to annually review and update it is to effectively promote required compliance with the PEL and/or SECAL or, in the alternative, where reducing airborne cadmium levels to the PEL or SECAL is not feasible, to effectively aid the employer in reducing employee air cadmium levels to the lowest feasible levels. OSHA recommends that records of routine maintenance of equipment, required to achieve stability in the control of exposures, be maintained and be accessible for review by OSHA. If circumstances change significantly (e.g. process changes or advancements in engineering controls where it previously was infeasible to achieve the PEL or SECAL by engineering and work practice controls), the employer is required to review and update the compliance program as needed.
OSHA has set out in very general terms the required elements of a compliance plan. The elements are similar to those required under the lead and arsenic standards (29 CFR 1910.1025 (e)(3)(ii); 29 CFR 1910.1918 (g)(2)(ii)). OSHA believes that by requiring certain elements in compliance plans the Agency will direct the employer's attention to these elements and communicate a sense of what a compliance plan entails. OSHA further believes that requiring a detailed implementation schedule will facilitate timely compliance. The more effective the compliance plan, the more likely it is that the employer will achieve compliance within the standard's deadlines.
The required elements of the plan include a description of the relevant aspects of each operation in which cadmium is emitted; a report of the technology considered in meeting the air cadmium limit; a description of the specific methods that will be used to achieve compliance, including the underlying documents justifying the choice of methods; air monitoring data characterizing cadmium emission sources; a detailed implementation schedule, with progress documented by appropriate underlying documents; a work practice program; and a written plan for emergency situations.
OSHA has made another minor change to the proposal by adding paragraph (f)(3), which pertains to mechanical ventilation. The paragraph is basically the same as paragraph (e)(5) in the lead standard (29 CFR 1910.1025) and similar in part to paragraph (e)(4) in the cotton dust standard (29 CFR 1910.1043). Mechanical ventilation is generally the most important engineering control for controlling cadmium exposure. Consequently, the Agency has made it explicit under paragraph (f)(3)(i) that when ventilation is used to control exposure, measurements that demonstrate the effectiveness of the system in controlling exposure, such as capture velocity, duct velocity, or static pressure, should be made to ascertain and maintain the effectiveness of the ventilation equipment. This provision was included to facilitate understanding of good general maintenance practices. It is not expected that this provision will add additional costs to an employer's routine maintenance procedures.
The Agency further specifies under paragraph (f)(3)(ii) that measurements of the system's effectiveness in controlling exposure should be made within a reasonable time period, i.e., within five days, after any changes in change in production, process, or control that might result in a significant increase in employee exposure to cadmium. Under (f)(3)(iii), it is specified that if air from an exhaust ventilation system is to be recirculated into the workplace, the system shall have a high efficiency filter and be monitored to assure effectiveness. In addition, under (f)(3)(iv), OSHA requires that employers develop and implement procedures to minimize employee exposure to cadmium when maintenance of ventilation systems and changing of filters is being conducted.
OSHA believes that paragraph (f) of this standard, which requires the employer to give preference to engineering controls and work practices over the use of respirators, is protective and encourages employers to pursue a cost-effective approach to controlling cadmium exposure.
Respiratory Protection: Paragraph (g).
With regard to respiratory protection, this final standard adopts the proposed provisions with little or no substantive modification. The provisions of this standard are in keeping with requirements for respiratory protection in other OSHA health standards (Lead 29 CFR 1910.1025; Benzene 29 CFR 1910.1028), and with recent developments in the field.
Respirators are necessary as supplementary protection to reduce employee exposure when engineering and work practice controls cannot achieve the necessary reduction to or below the PEL. Respirators may also be necessary at other times: while such controls are being implemented, during emergency situations, during intermittent exposures under the 30-working day exclusion when engineering and work practice controls are not required, wherever an employee is exposed to cadmium above the PEL in an industry to which a SECAL is applicable, and for brief or intermittent exposures that cannot be controlled through engineering and work practice controls. A respirator also must be provided by the employer for all authorized employees in regulated areas.
Finally, OSHA in paragraph (g)(1)(vi), also requires employers to provide a respirator to any employee who is exposed to cadmium at or above the action level who requests one. This provision is the same in the final standard as in the proposal (55 FR 4052, at 4123). It also is similar to a provision in the lead standard (29 CFR 1910.1025 (f)(1)(iii)). The employer under paragraph (g)(2)(ii) is also required to provide a powered air purifying respirator (PAPR) to any employee entitled to be provided a respirator whenever that employee requests a PAPR and the PAPR will provide adequate protection to the employee. This provision clarifies the language in paragraph (g)(2)(ii) of the proposal to make it consonant with paragraph (g)(1)(vi) in the proposal and final standard.
Because of the risk of serious adverse health effects from cadmium exposures, OSHA accepts the need for requiring respirators in the above mentioned circumstances in order to reduce an employee's cumulative dose of cadmium.
The final standard requires that whenever respirators are required to reduce employee exposures, the employer must provide the type of respirator appropriate to the exposure level at no cost to the employee. Employers must also assure that respirators are used properly when required. The standard contains specific requirements for the use, selection, maintenance, and fitting of respirators, which are derived from OSHA's experience and are consistent with widely accepted principles of industrial hygiene and with other OSHA health standards (Asbestos, 29 CFR 1910.1001; Lead, 29 CFR 1910.1025; Benzene, 29 CFR 1910.1028; Formaldehyde, 29 CFR 1910.1048).
Table 2 lists the type of respirator to be used at each airborne concentration of cadmium in the workplace. While the employer must select the appropriate respirator from the table on the basis of the airborne concentration of cadmium, the employer may always select a respirator providing greater protection, (i.e., a respirator prescribed for higher concentrations of cadmium than the concentration to which the employee is exposed). The standard further requires that the respiratory protection program implemented by the employer conform to that set forth in 29 CFR 1910.134, which contains the basic requirements for proper selection, use, cleaning and maintenance of respirators. Since OSHA's risk assessment indicates that cadmium is highly toxic, OSHA has required all air purifying respirators to be equipped with a HEPA filter, regardless of the exposure level. OSHA believes that HEPA filters provide an extra margin of safety at all levels of exposure. While other non-HEPA filters may perform efficiently at very high concentrations of cadmium in air, the HEPA is the most efficient, e.g., 99.97% removal at higher concentrations. Moreover, only the HEPA filter is efficient at lower PELs, e.g., PEL < 50 ug/m(3) (Asbestos, 51 FR 22695, June 20, 1986).
OSHA is especially concerned about efficiently filtering small size particles, i.e., the particles for which the HEPA filter is the most effective. Thus, OSHA, in requiring the use of HEPA filters is concerned especially to protect workers exposed to low levels of cadmium in the form of small particles. OSHA believes that the requirement for HEPA filters will provide a needed degree of safety for these workers, that cannot be provided as effectively by other filters. The requirement for HEPA filters is consistent with other OSHA health standards (Lead, 29 CFR 1910.1025; Asbestos, 29 CFR 1910.1001).
The standard also requires employers to permit employees to leave regulated areas to readjust the respirator facepiece for proper fit,to change the filters, or to replace the respirator. It also requires employers to permit employees to leave the regulated area to wash their faces or their respirators to avoid potential skin irritation associated with respirator use. These requirements encourage and facilitate the proper use of respirators by employees through authorizing employees to take specific actions to assure the effective functioning of the respirators and to reduce the probability of certain adverse side effects from wearing respirators. These requirements are consistent with provisions in other health standards (e.g. Inorganic Lead, 29 CFR 1910.1025) and with the proposed cadmium standard (55 FR 4123).
The standard requires fit testing of all respirators to assure at least a minimally acceptable fit. Quantitative fit testing requires the use of moderately sophisticated testing equipment and is more expensive to perform than qualitative fit testing. This may reduce its availability in some worksites. Also, testing services may not be available in all parts of the country to provide quantitative fit testing services for small employers. To tailor the respirator fit testing to the circumstances of the employer's establishment, OSHA permits the employer to choose either quantitative or qualitative fit testing if cadmium exposures are less than 10 times the PEL. Mandatory protocols for whichever type of testing the employer chooses are set forth in Appendix C to this standard.
OSHA is requiring quantitative fit testing of all tight-fitting air-purifying respirators (either positive or negative-pressure) when used at exposures exceeding 10 times the PEL, 50 ug/m(3), because proper fit is essential to the performance of these respirators. Quantitative fit testing is a procedure whereby the level of penetration of a test agent of known concentration is measured inside the facepiece of the respirator. Quantitative fit testing is generally recognized as the better method for determining how well a respirator fits a particular individual. It provides a quantitative assessment of the extent of the fit (i.e. the fit factor). It allows the employer to test various respirators on the employee until the optimum or best fitting respirator is identified and selected for the employee. Whenever quantitative fit testing is used to assess the fit of a negative pressure respirator, a fit factor of at least 10 times the protection factor for that class of respirators shall be achieved for an acceptable fit. This is a minimum requirement. Whenever quantitative fit testing is used to assess the fit of a positive pressure respirator, the employer shall test a negative pressure respirator made by the same manufacturer, which is the same model and size, to determine whether the facepiece-to-face seal is adequate. The seal is acceptable if the fit factor is at least 10 times the protection factor for the relevant class of negative pressure respirators.
The regulatory language in the proposal, which required that both negative and positive pressure air purifying respirators be fit tested, was not clear on this point. A commenter stated that the proposed requirement for quantitative fit testing for negative pressure air purifying respirators and powered-air-purifying respirators (PAPRs) should be extended to all tight-fitting respirators, including self contained breathing apparatus (SCBAs) and supplied air respirators (L19-53). Language has been added to paragraph (g)(4) to clarify the requirement to fit test tight-fitting supplied-air respirators and SCBAs.
Obtaining a proper respirator fit may require fit testing a variety of different mask sizes from several manufacturers to select the facepiece with the best fit (i.e., least leakage around the faceseal) for each employee. A properly fitted facepiece helps to reduce inhalation leakage to a minimum. If the fit factor is not at least minimally acceptable, the respirator shall not be worn. With ill-fitting respirators, cadmium contaminated workplace air may enter the facepiece through gaps and leaks in the facepiece seal.
Qualitative fit testing does not provide a numeric measure of the tightness of the fit but simply determines whether a respirator "fits" or not. Qualitative fit testing is a technique whereby a person wearing a respirator is tested to see whether a test agent with a detectable odor or taste threshold can be detected inside the respirator. If the odor or taste cannot be detected, the respirator is said to "fit". Qualitative fit testing is more subjective than quantitative testing because it depends on the individual's ability to detect the test agent.
OSHA recognizes that quantitative fit testing may have some advantages over qualitative fit testing. However, for employees exposed to lower levels of cadmium, (10 times the PEL or less) qualitative testing conducted in accordance with the protocols described in Appendix C can adequately assess the fit of the respirator to assure that each employee is assigned and wears the respirator that provides a proper fit with the least possible leakage. It is important that all employees who wear respirators be medically screened to determine employee fitness for respirator usage. Respirator use may constitute a burden on the employee's cardiopulmonary system. This burden may result in symptoms such as shortness of breath, chest pain, dizziness or fatigue. These symptoms may be exacerbated by pre-existing lung disease such as chronic bronchitis, emphysema, asthma or pneumoconiosis.
Paragraph (l)(6)(i) of this standard requires that limited medical examinations be made available to workers with a job that requires the use of a respirator. This differs from the proposal which required a full medical examination (55 FR 4125). The limited medical examination must be made available prior to the employee's assignment to a job requiring a respirator unless the employee has received a medical examination within the preceding 12 months that satisfies all the requirements of paragraph (l)(6)(i)(A)-(D). The medical examination is to assure that individuals who are incapable of wearing a respirator or who might suffer some adverse health effect from wearing a respirator are not required to wear one. The medical examination is made available to determine whether any health conditions exist that would affect the employee's ability to wear a respirator. If an examining physician determines that an employee will be unable to continue to function normally while wearing a respirator in a job where exposures exceed the PEL, then the employee shall be afforded the opportunity for transfer as set forth in paragraph (l)(11). This is consistent with OSHA's previous health standards (e.g., Asbestos, 29 CFR 1910.1001; paragraph (g)(3)(iv)).
This does not mean that medical removal protection (MRP) under paragraph (l)(11) applies to a new employee who is determined in a pre-employment medical examination for respirator use to be unable to wear a respirator. Nor does it mean that MRP applies to a worker determined to be medically unable to wear a respirator who seeks to transfer to a job for which a respirator is required. The MRP provisions relating to an employee's inability to wear a respirator apply only to a worker who already is functioning in a job where a respirator is required who is then determined to be medically unable to wear a respirator.
OSHA has not exempted occasional users of respirators from the medical evaluation requirement. OSHA believes such users need to be evaluated for their fitness to wear respirators as well. In addition, applying such an exemption might create administrative problems (Docket Number H-049, Respiratory Protection Revision).
The standard requires employers to provide a proper respirator at no cost to any employee with cadmium exposures at or above the action level who requests one. Due to the serious nature of the adverse health effects of cadmium exposure, workers exposed at or above the action level may choose to use respirators. OSHA generally agrees with the commenter who argued that OSHA should have a consistent medical surveillance policy for all respirator users, including voluntary users (Ex. 19-9). As stated, medical surveillance under paragraph (l) is triggered at exposure levels at or above the action level. Similarly, an employee exposed at or above the action level has the right to request a respirator. Therefore, workers who voluntarily request a respirator are likely to already be covered by medical surveillance.
In addition, unless otherwise indicated, all other relevant requirements apply equally to voluntary respirator users. Thus, under paragraph (l)(6), the employer must provide the voluntary user with a limited medical examination to determine the employee's fitness to wear a respirator prior to wearing one. Similarly, the employer must maintain the voluntary users' respirators in good repair and provide an adequate supply of filter elements. If employees entitled to be provided a respirator by the employer were treated differently, their entitlement might be compromised. For all workers covered by this standard who wear a respirator and for workers who are participating in medical surveillance under this standard, an examination for fitness to wear a respirator is effectively part of routine medical surveillance.
For a respirator program to be effective, the employee must be properly trained to wear the respirator, to know why the respirator is needed, and to understand the limitations of the respirator. An understanding of the hazards involved also is necessary to enable employees to take steps for their own protection.
Commenters and witnesses in the rulemaking raised several main points about OSHA's proposed requirements for respiratory protection. On the one hand, a number of commenters criticized these requirements for not being strict enough. NIOSH, for example, presented a very stringent approach to respirator usage (Exs. 57; 106). NIOSH had several recommendations regarding respirator protection for cadmium exposed workers. NIOSH opposed routine, full-time use of respirators and allowing the use of negative pressure respirators and instead recommended that only the most protective positive pressure supplied-air and SCBA respirators be used, since cadmium is an occupational carcinogen (Ex. 57; NIOSH, Tr. 7/17/90, p. 51). OSHA has never followed such a stringent policy on respirator use. If respirators other than the positive pressure respirators NIOSH recommended are permitted, NIOSH recommended that the assigned protection factors given in the NIOSH Respirator Decision Logic be used, in particular that tight fitting PAPRs be given a protection factor of 50 (OSHA proposed 250), and that loose fitting PAPRs be given a protection factor of 25, as OSHA proposed. (Tr. 7/17/90, pp. 57-58, 77, 83, 164-65, 212-14). In view of the disagreement regarding protection factors (see below), OSHA decided not to change its proposed protection factors and to allow further comments on this issue to be placed in the record of the proposed Respiratory Protection Revision standard (Docket Number H-049).
On the other hand, several commenters criticized OSHA's proposal for being too strict regarding respirators. Thus, one commenter argued that PAPRs and supplied air respirators should be assigned a protection factor of 1000 in the final standard (Ex. 19-20). Another commenter criticized OSHA for assigning a protection factor (PF) as low as 25 to loose fitting PAPRs, instead of the current PF of 1,000 or at least 100 (Ex. 19-39). Still another criticized the Agency for not assigning a PF higher than 10 to half-mask, negative pressure respirators, which it claimed might in some situations be more effective and safer than full facepiece, negative pressure respirators or PAPRs (Tr. 6/12/90, p. 7). Another commenter asked, in light of NIOSH's disapproval of disposable "high-efficiency" respirators for use against asbestos because of its carcinogenicity, whether such respirators were usable for cadmium exposures (Ex. 19-18). One questioned the need to provide PAPRs on request when exposures did not exceed the PEL (Ex. 19-22).
OSHA has extensively reviewed the respirator performance studies supporting the protection factor of 10 given to half mask respirators as part of the Respirator Standard Revision (Docket No. H-049). The concept of giving an increased protection factor to a respirator based on higher fit factors measured during quantitative fit testing has been discredited. Workplace protection factor studies (Docket H-049 Exs. 27-1; 27-2; 27-9; 38-2; 38-7) and laboratory fit testing studies (Docket H-049 Exs. 2; 38-3) that have been reviewed as part of the 29 CFR 1910.134 respirator standard revision show that the fit factors achieved during quantitative fit testing are not achieved in the workplace. While half masks can achieve fit factors greater than 10 during QNFT, they have not been able to demonstrate consistent workplace protection levels greater than 10. Consequently, the protection factors OSHA had listed for cadmium respirators in the proposal (55 FR 4123) are not being changed. The few comments on protection factors that were received do not justify changing the protection factors listed.
A question about the use of disposable high-efficiency respirators such as the 3M Model 9970 for protection against cadmium was raised by Bruce Crowell of the Duke Power Company (Ex. 19-18). OSHA is concerned that the effectiveness of such respirators against carcinogenic dusts and fumes (NIOSH, Tr. 7/17/90, p. 51; Ex. 57) is limited by problems in achieving an adequate fit. This concern has been addressed in several OSHA standards. The cotton dust standard allowed a protection factor of 5 for disposable dust/mist respirators due to problems with respirator fit. The asbestos standard prohibited the use of disposable respirators, with or without HEPA filters. However, there are HEPA disposable respirators on the market with elastomeric facepieces that do not have these problems with fit. For the time being, OSHA will accept the use of HEPA disposable respirators with cadmium. Nonetheless, caution is urged in using HEPA disposable respirators, particularly single use HEPA respirators without elastomeric facepieces.
Michael Dwyer of the McDonnell Douglas Corporation (Ex. 19-22) commented that employers should be required to provide PAPRs on request only if exposures exceed the PEL. Mr. Masaitis, testifying for the American Iron and Steel Institute, stated that it "is unreasonable to require that an employer provide a PAPR to an employee simply because one is requested" when other adequate protection is available (Tr. 7/18/90, pp. 282-283). The cadmium standard requires that respirators, including PAPRs, be provided by employers to employees exposed at or above the action level on request. PAPRs can minimize the physiological burden on lung function imposed by air purifying respirators. Dr. Tyner of Gates Energy Systems commented that lung function should not interfere with a worker's ability to wear a respirator as long as positive pressure respirators are available (Ex. 19-2). PAPRs can also provide added protection. OSHA, therefore, will continue to require that employers provide a PAPR to an employee exposed at or above the action level when requested.
Several other commenters criticized aspects of the protocols for fit testing in Appendix C (Exs. 19-5; 19-7; 19-9; 19-20).
Mr. G. F. Stone of the Tennessee Valley Authority commented on the requirement in Appendix C that the employer assign specific individuals to assume full responsibility for the qualitative/ quantitative fit testing program (Ex. 19-5). He recommended that the employer be required to assign a single individual to be responsible for the entire respirator program, and that individual could then delegate the fit testing responsibilities to appropriate individuals. This cadmium standard permits an employer to designate one individual to be responsible for the entire respirator program. Such a requirement for a single respirator program administrator is being considered for inclusion as part of the respirator standard revision (29 CFR 1910.134). However, that proposed revision and this cadmium standard in their fit testing procedures require that individuals be assigned to be responsible for the qualitative and quantitative fit testing programs who are trained and experienced in selecting proper fitting respirators, performing fit testing, calibrating fit test equipment and interpreting fit testing results. This specialized knowledge and ability to perform fit testing goes beyond that normally expected of an overall program administrator. The purpose of this requirement is to be sure that the fit testing program is performed only by appropriately trained personnel.
In Appendix C, the quantitative fit testing methods state that corn oil or sodium chloride are the only accepted challenge aerosols. Mr. G.F. Stone of the Tennessee Valley Authority (Ex. 19-5) urged OSHA to revise this to permit the use of Portacount fit testing instruments, which use ambient air particles as the challenge aerosol. The quantitative fit test methods in Appendix C have been shown to be accurate through extensive validation testing. In addition, the use of the Portacount is currently permitted under other OSHA standards by a compliance interpretation that treats their use as a de minimis violation of the fit testing requirements (Ex. L-166). The cadmium standard will continue this interpretation of the Portacount. As part of the respirator standard revision (29 CFR 1910.134), the manufacturer of the Portacount has the opportunity to submit validation testing of its fit testing method and instrumentation to show that it is capable of determining fit factors as accurately as the corn oil and sodium chloride systems currently recognized, in order to become a validated fit test method. If the Portacount becomes a validated fit test method, the Appendix C fit test methods will be revised to reflect this.
The Maryland Occupational Safety and Health program (MOSH) recommended that the grimace be deleted from the fit test exercises so that "workers will not fail otherwise acceptable fit tests" (Ex. 19-7). The purpose of the grimace exercise is to determine whether the respirator being fit tested will reseat itself on the face after the respirator seal is broken during the grimace exercise. In quantitative fit testing, the test instrumentation should show a rise in challenge agent concentration inside the mask during the grimace exercise and a drop once the respirator reseats itself. If the respirator fails to reseat, the subsequent test exercises will show excessive leakage and result in failing the test. Since even a properly fitting respirator may show increased penetration during the grimace exercise, the penetration measured during the grimace exercise is not to be used in calculating the fit factor. The language in Appendix C has been modified to reflect this.
MOSH also recommended that the saccharin solution aerosol protocol be corrected by deleting the reference to disposable dust respirators to reflect the fact that disposable dust respirators not equipped with high efficiency filters are not permitted by the proposed cadmium standard. The proposed and final cadmium standards require the use of HEPA filters, which means that the irritant smoke and isoamyl acetate protocols can be used for qualitative fit testing. The saccharin protocol, which uses a large particle size test aerosol, is not necessarily appropriate for cadmium exposure with that type of respirator. OSHA agrees with MOSH that the saccharin solution protocol is not now needed for the respirators permitted under the cadmium standard, so it has been deleted from Appendix C.
Frank Wilcher (Ex. 19-20) of the Industrial Safety Equipment Association (ISEA) questioned the requirement in Appendix C that employees be offered a range of respirator facepieces to choose from, in at least five different sizes, and from two manufacturers. These requirements were called "excessive and unnecessarily inflexible" since an adequate fit can be obtained without offering respirators from two different manufacturers. The number of sizes and models offered, the commenter declared, should be a function of the size of the workforce.
OSHA understands that in a particular workplace a limited selection of respirator sizes and models could possibly be made to fit all those who need one. However, such occurrences cannot reasonably be relied upon as a pretext for limiting respirator selection options. The increased numbers of individuals in the workforce, such as women and minorities, with facial types and sizes that are different from, say, those of white and black males means that a wide range of facepiece sizes is needed to assure adequate fits. The purpose of fit testing is to achieve the best possible fitting respirator and this is only possible when an adequate selection of models and sizes is available. There is no standardization on sizes among respirator manufacturers. Each manufacturer develops their own facepiece molds and none correspond identically. This means that one manufacturer's medium size facepiece may fit an individual, while another manufacturer's medium size facepiece may not. Respirators come in different sizes, some in three different sizes (small, medium, large) while others only come in two sizes (large, medium). Therefore, the cadmium fit testing protocols continues to require that a selection of at least five facepiece sizes from two different manufacturers be available to provide a wide range of possible facepiece fits. This requirement is the same as the one in Appendix C, paragraph I.B.1. in the asbestos standard (29 CFR 1910.1001).
Mr. Stephen Wilson of the Duriron Company (Ex. 19-9) commented that the requirements in section (g) and Appendix C are too detailed, and should be part of the respiratory protection standard (29 CFR 1910.134) and included in the cadmium standard only by reference. OSHA agrees that the ideal place for these detailed respiratory protection provisions is in the respirator standard. However, the respiratory protection standard revision will not be finalized until well after this cadmium standard is published. To achieve the level of respiratory protection appropriate for cadmium exposures it is necessary to include these provisions in the cadmium standard now. Subsequently it may be possible, once the respiratory protection standard revision is finalized, to remove these detailed provisions from the cadmium standard and incorporate by reference the respiratory protection standard provisions.
Emergency Situations: Paragraph (h).
The language in this final standard concerning emergency situations is basically the same as the language in the proposal. It requires the employer to develop and implement a written plan for dealing with emergencies involving substantial releases of airborne cadmium. The plan must include provisions for the use of appropriate respirators and personal protective equipment. In addition, employees not essential to correcting the emergency must be restricted from the area, and normal operations in the area must be halted until the emergency is abated. Examples of such emergencies may include ruptures of containers filled with cadmium in dispersible form and failures of control or operating equipment. Emergency plans are necessary to direct employees to act in ways that maximize their personal protection and minimize the hazards in the event of an emergency. To that end, employees not engaged in correcting the emergency must be prohibited from the area and normal operations in the area halted until the emergency is abated.
Protective Work Clothing and Equipment: Paragraph (i).
Protective clothing and foot coverings are required to prevent contamination of the employee's body and the employee's street clothing and shoes. Protective clothing, if provided and used properly, helps to prevent cadmium exposure beyond the workplace. By contrast, wearing contaminated street clothing outside the worksite would lengthen the duration of the employee's exposure and could cause cadmium to accumulate in employees' cars and homes, exposing other individuals to the hazard.
This final standard, with substantial modifications, adopts the requirements of the proposed cadmium standard regarding protective clothing and equipment. These requirements are typical of other OSHA health standards and are based upon widely accepted principles and conventional practices of industrial hygiene.
The final standard requires that the employer provide protective clothing and equipment to employees who are exposed to cadmium at levels above the PEL and to employees exposed at any level where skin or eye irritation associated with cadmium exposure occurs. This is a minor change from the proposal, which required protective clothing to be provided if "the possibility of skin or eye irritation exists from cadmium exposure...." (55 FR 4124). As the discussion in the preamble to the proposed cadmium standard (55 FR 4112) makes clear, OSHA did not intend that the mere "possibility" of associated skin or eye irritation should trigger the obligation for the employer to provide protective clothing and equipment to employees, because that possibility might exist in nearly all workplaces with exposure to cadmium dust. According to the preamble in the proposal it was the occurrence of such irritation that triggered the employer's obligation to provide protective clothing. This final standard follows that intention.
In addition, the language in paragraph (i)(1) of the final standard clarifies OSHA's ongoing understanding that appropriate protective work clothing and equipment must prevent contamination of the employee and the employee's garments. If they did not, they would not be "protective".
Personal protective clothing and equipment includes, but is not limited to, coveralls, shoe covers, head coverings, and goggles. Clean protective clothing and equipment are to be provided by the employer at least weekly, but OSHA recommends that they be provided daily to assure their effectiveness. Protective clothing and equipment is to be provided to each affected employee at no cost to the employee. This is consistent with similar requirements in the lead and arsenic standards, 29 CFR, 1910.1025 (g)(2), and 1910.1018(j)(2), respectively. Removal of cadmium from protective clothing by blowing, shaking, or any other means that disperse cadmium into the air is prohibited.
The standard also requires that the employer be responsible for cleaning, laundering and disposing of the required protective clothing and equipment, to eliminate any potential exposure that might result if the clothing and equipment were laundered or cleaned by the employee at home. Like the proposal (55 FR 4124), the final standard requires that protective clothing and equipment be cleaned, maintained, and replaced as needed in order to assure its effectiveness.
The standard provides that the employer shall assure that all protective clothing is removed at the end of each work shift and only in change rooms. The contaminated clothing and equipment that is to be laundered, cleaned, or disposed of is required to be stored in a closed container prior to laundering or disposal so that contamination of the change room is minimized and exposure of employees who later handle the clothing also is minimized. These employees are further protected by the requirement that they be informed of the potentially harmful effects of cadmium exposure and that warning labels be placed on the bags or containers. Since these containers are to be located in the change room, it is appropriate to limit workers' removal of their contaminated clothing to that area.
The standard obligates the employer to provide personal protective clothing at no cost to the employee. Since the employer is responsible for reducing exposures below the permissible exposure limit, the obligation to provide personal protective equipment properly rests on the employer. The employer also is in the best position to provide the correct type of clothing and keep it in the condition necessary to perform its protective functions.
Hygiene Facilities and Practices: Paragraph (j).
This final standard, like the proposal, requires employers to provide hygiene and lunchroom facilities for employees exposed to cadmium at levels above the PEL and to assure employee compliance with basic hygiene practices to minimize additional sources of exposure to cadmium that may accumulate on a worker's clothes or body. The final standard makes it clearer that all of these facilities must comply with the requirements of 29 CFR 1910.141. For all employees who are exposed above the PEL, the employer must provide adequate shower and washing facilities, clean rooms for changing clothes, and lunchroom facilities. In addition, employers must assure that employees use the facilities as required by the standard. Employers also must assure that employees exposed above the PEL must observe prohibitions on the availability and use of cosmetics, tobacco and chewing products, and food and beverages in regulated areas under paragraph (e). OSHA expects that strict compliance with these provisions will virtually eliminate several sources of cadmium exposure that substantially contribute to overall exposure levels.
Several of these facilities and practices are presently required under current OSHA standards for General Environmental Controls in Subpart J of 29 CFR Part 1910. For example, section 1910.141 (e) states that if a standard requires employees to wear protective clothing, then the employer must provide change rooms with separate storage facilities for street and work clothing. In addition, section 1910.141 (g) requires the employer to prohibit the consumption of food and beverages in areas where there is exposure to toxic substances. The hygiene provisions of paragraph (j) of this standard augment the requirements of 29 CFR 1910.141 with additional requirements that are specifically applicable to cadmium exposure and consolidate all related provisions.
OSHA believes it is essential for employees to have separate locker and storage facilities for street and work clothing to prevent cross-contamination of their street clothes. This provision will minimize employee exposure to cadmium after the work shift ends, because it reduces the period during which employees may be exposed to cadmium-contaminated work clothes.
Showering also reduces the worker's period of exposure to cadmium by removing cadmium which may accumulate on the skin and hair. Requiring employees to change out of work clothes, which are then segregated from their street clothes, to shower before leaving the plant, and to leave work clothing at the workplace significantly reduces the movement of cadmium from the workplace. These steps assure that the duration of cadmium exposure does not extend beyond the workshift and provide added protection to employees and their families.
The final standard also requires employers to provide employees whose airborne exposure to cadmium is above the PEL with readily accessible lunchroom facilities in which tables maintained for eating are free of cadmium and no employee is exposed at any time to a concentration of cadmium at or above 2.5 ug/m(3). This is the main change from the proposed provisions regarding hygiene facilities, which required employers to provide lunchrooms with a positive pressure and a tempered and filtered air supply. By contrast, the final standard is written in performance language. It is OSHA's intention, of course, that employees are not to be exposed to uncomfortable temperatures.
OSHA makes this change to provide more flexibility to employers while still assuring adequate protection to employees. Although the employer may, in any event, often have to provide the type of lunchroom specified in the proposal in order to comply with the performance requirement of the final cadmium standard, OSHA recognizes that there may be many instances where employers can comply without having to do so. OSHA agrees with the industry commenter who said that "where the lunchroom is not adjacent to cadmium-contaminated areas" and there is no cross contamination of the lunchroom, a positive pressure, filtered air supply is unnecessary (Ex. 19-22). OSHA therefore sees no reason to require the provision of such lunch rooms where they are not needed.
OSHA believes that the requirements for lunchroom facilities in this final standard are at least as protective as the proposed requirements. For example, the final standard, unlike the cadmium proposal, requires that tables in the lunchroom facility must be maintained free of cadmium and that no employee there may be exposed to a concentration of cadmium at any time at or above 2.5 ug/m(3). The 2.5 ug/m(3) limit is not an 8 hour TWA PEL but is an absolute prohibition of levels that high or higher at any time.
OSHA feels it is imperative that employees have a clean place to eat to minimize the possibility of cadmium contaminated food and to reduce the likelihood of additional exposure to loose cadmium dust through inhalation or ingestion. Since OSHA believes that employers have several equally protective options to achieve these goals, the standard has not set specific requirements.
Employers must also assure that employees who work in regulated areas wash their hands and face prior to eating or smoking and that employees not enter the lunchroom wearing protective clothing unless it is properly cleaned beforehand. Employers are given discretion to choose any method for removing surface cadmium from the clothing that does not disperse the dust into the air. These requirements are basically the same as those in other OSHA standards (e.g., paragraph (i)(4) of the lead standard, 29 CFR 1910.1025).
Housekeeping: Paragraph (k).
Like other OSHA health standards dealing with toxic dusts (Asbestos, 29 CFR 1910.1001), the cadmium standard imposes the general housekeeping requirement to maintain all surfaces as free as is practicable of accumulations of cadmium. In the final standard the strong preference for vacuuming (or equally effective and protective methods of cleaning) that is incorporated in the proposal is made more explicit. The standard requires that, where possible, surfaces contaminated with cadmium be cleaned by vacuuming or other methods that minimize the likelihood of cadmium becoming airborne. The standard allows shoveling, dry or wet sweeping, and brushing only if the employer shows that vacuuming or other methods that are usually as efficient as vacuuming are not effective under the particular circumstances. It also requires that vacuuming be done with cleaners equipped with HEPA filters to prevent the dispersal of cadmium into the workplace. The standard differs from the proposal (55 FR 4124) in that it allows the use of compressed air for cleaning when the compressed air is used in conjunction with a ventilation system designed to capture the dust cloud created by the compressed air. In addition, items contaminated with cadmium and consigned for disposal are to be collected and disposed of in sealed impermeable bags or other closed impermeable containers.
These housekeeping provisions are exceptionally important because they minimize additional sources of exposure that engineering controls generally are not designed to control. Good housekeeping is a cost effective way to control employee exposure levels by removing from the worksite cadmium dust that can become entrained by physical disturbances or air currents and carried into employee breathing zones.
Medical Surveillance: Paragraph (l).
(1) General. The medical surveillance provisions of this final standard were developed from the proposal in light of the entire record. More specifically these provisions are derived in no small part from the proposal and the responses to it, as further articulated in a July 2, 1990, memorandum sent by OSHA to all the hearing participants (Ex. 46). That memorandum summarized the comments and testimony in the rulemaking to date, indicated OSHA's then current thinking, and requested further information, comment, and testimony at the upcoming hearing in Denver. The response to that memorandum, which was substantial (e.g., cites), has also shaped the medical surveillance program in the final standard.
The medical surveillance provisions of paragraph (l) generally are aimed at accomplishing three main interrelated purposes: first, identifying employees at higher risk of adverse health effects from excess, chronic exposure to cadmium; second, preventing cadmium-induced disease; and third, detecting and minimizing existing cadmium-induced disease. The core of medical surveillance in this standard is the early and periodic monitoring of the employee's biological indicators of: (a) recent exposure to cadmium; (b) cadmium body burden; and (c) potential and actual kidney damage associated with exposure to cadmium.
It is not yet known how to biologically monitor human beings to specifically prevent cadmium-induced lung cancer or certain other cadmium-induced lung diseases. By contrast, the kidney can be monitored to provide prevention and early detection of cadmium-induced kidney damage. Since, for non-carcinogenic effects, the kidney is considered the primary target organ of chronic exposure to cadmium, the medical surveillance provisions of this standard effectively focus on cadmium-induced kidney disease. Within that focus, the aim, where possible, is to prevent the onset of such disease and, where necessary, to minimize such disease as may already exist. The by-products of successful prevention of kidney disease are anticipated to be the reduction and prevention of other cadmium-induced diseases.
More specifically, for veteran workers, the aim of these medical surveillance provisions is to promptly identify employees with excessive, cumulative exposure to cadmium, especially those who were excessively exposed to cadmium before this standard takes effect. Once these employees are identified, the aim is to monitor them, ideally to prevent cadmium-induced kidney disease, or at least to minimize it. For cadmium exposed workers who have not yet been excessively exposed to cadmium, the aim is to identify those at higher risk and to prevent excess exposure and resulting disease.
In order to assure that biological monitoring results are accurate and reliable, an issue raised during the rulemaking (Ex. 19-29), OSHA in paragraph (l)(1)(iv) of this standard requires that the employer make sure that collecting and handling of biological samples is done in a manner that assures reliability and that analyses are performed in laboratories proficient in the particular analyte. OSHA has developed a non-mandatory protocol to guide employers and laboratories in these regards (See Appendix F). An employer who follows this protocol will be in compliance with the performance requirements in paragraph (l)(1)(iv) of the standard. However, the employer is free to follow other procedures so long as they provide at least the same degree of accuracy and reliability.
As discussed below in connection with the medical surveillance program, the lowest biological triggers incorporated in this standard are above existing levels of detection and are distinguishable from lower levels that for purposes of this standard are treated as "normal" levels of these biological parameters in the general population.
In addition, the degree of accuracy and reliability described in Appendix F for biological monitoring required by this standard is achievable with currently available equipment. As a result, OSHA feels comfortable with triggering enhanced medical surveillance and other actions from such biological monitoring results. To assure the necessary quality of results, OSHA recommends that laboratories that analyze levels of cadmium in urine (CdU), cadmium in blood (CdB), and Beta-2 microglobulin in urine (B(2)-M) should demonstrate their proficiency in certain, specified ways.
The scope of medical surveillance in this standard is designed to accomplish the purposes set out above. OSHA in its proposed cadmium rule originally sought to include in medical surveillance all workers who are, or may in the future be exposed to airborne levels of cadmium at or above the action level or the excursion limit (55 FR 4124). The excursion limit has since been deleted, as discussed above. However, in the proposal, the use of the action level of 2.5 ug/m(3) alone was both too broad and too narrow. On the one hand, including all workers who are or will be occupationally exposed to airborne levels of cadmium at or above the action level would allocate scarce resources to monitoring many workers who may not be at significant risk of disease, because by the nature of their work their cadmium exposures are only intermittent and at very low levels (Exs. 8-732; 12-10-G; 148; 120). On the other hand, limiting coverage only to workers who may be currently exposed to cadmium mistakenly ignores the possibility of excess risk of cadmium-related illness among workers who were previously exposed but no longer are (Ex. 19-2). In the case of workers whose previous exposure occurred before the effective date of this standard, the levels of cadmium to which many workers were exposed probably were considerably higher than the new PEL. As a result, these previously exposed workers may have higher body burdens of cadmium and may be in particular need of medical surveillance. Kidney dysfunction arising from chronic, excess exposure to cadmium, for example, occurs among workers with a certain minimum accumulation of cadmium in their kidneys (Ex. 144-3-C; Section VI - Quantitative Risk Assessment; Summary of Kidney Dysfunction).
Consequently, in response to comments (Exs. 19-18; 101) the scope of medical coverage in paragraph (l)(1)(i) of the final cadmium standard is defined both more narrowly and more broadly than in the proposal. Not every worker who is or will be exposed to cadmium at or above the action level at work is covered. Instead, a certain threshold of exposure to cadmium is required to trigger medical surveillance. An employee will be covered by medical surveillance if the employee is or may be exposed at or above the action level of 2.5 ug/m(3) on 30 or more days per year. This is in line with testimony in the record (Tr. 7/19/92, pp. 14-17) and with previous OSHA health standards. In those standards medical surveillance for currently exposed employees frequently is triggered by exposure at or above the action level, which typically is set at half the PEL, on 30 or more days per year (Benzene, 29 CFR 1910.1018 (n)(1)(A); Lead, 29 CFR 1910.1025(j)(1)).
In addition, certain workers who no longer are exposed to cadmium but who were previously exposed by the current employer also will be included in medical surveillance under this standard. They will be included if prior to the effective date of this standard they might previously have been occupationally exposed at or above the action level to cadmium by the current employer unless they did not in those years work in those jobs for an aggregated total of more than 60 months. Although OSHA is not requiring employers to provide medical surveillance to workers previously exposed for less than 60 months, OSHA recommends that employers provide the same medical surveillance to all workers who worked for the current employer in cadmium exposed jobs for a total of 12 months or more prior to the effective date of this standard [See Benzene; 29 CFR 1910.1028 (i)(1)].
With regard to these veteran workers, because cadmium is retained for so many years in the body and because it is a cumulative toxin that can cause chronic disease, workers who were excessively exposed to cadmium before this new standard took effect must also be medically monitored, at least for a time, even if they no longer are currently exposed or cease to be exposed. Employees who were not exposed before the effective date of this standard and new employees who begin cadmium exposed work under the new PEL are not likely to be exposed to such high cumulative levels. Under the new PEL, workers are not likely to be exposed above the critical air concentration for susceptible populations of 225 ug/m(3) - years because the PEL is sufficiently low (Friberg et al., ref. in Ex. 4-27).
Veteran workers, however, may have exceeded this dose. In the past, many highly exposed workers were exposed to cadmium concentrations ranging between 40-50 ug/m(3). Five years of exposure to these levels would result in a cumulative cadmium dose ranging from 200-250 ug/m(3) - years. Thus, in order to protect susceptible populations from kidney dysfunction, OSHA chose 60 months (5 years) as the past total months of exposure to trigger medical surveillance for veteran workers. This provision of the standard is consistent with OSHA's approach in the benzene and arsenic standards. (See the benzene standard 29 CFR 1910.1028 under paragraph (i)(1)(i).) In the benzene standard, veteran workers were covered by the medical surveillance provisions if they had past exposure to 10 ppm for one month. One month of exposure to 10 ppm is equivalent to a cumulative dose of 0.83 ppm-years of benzene prior to the promulgation of the new benzene standard (i.e., 10 ppm x 1/12 = 0.83 ppm - years). Since the new benzene standard allows workers to be exposed annually to 1 ppm-years of benzene, 0.83 ppm - years represents about 80% of the annual allowed cumulative dose.
In the final cadmium standard, veteran workers would not be eligible for medical surveillance unless they have been exposed in the past to cadmium for five years. If veterans were exposed, for example for five years at or above the action level, they would have been exposed to more than 12.5 ug/m(3) - years (action level of 2.5 ug/m(3) x 5 years). This cumulative dose would constitute approximately 250% of the annual cumulative cadmium dose under the new PEL and proportionately is only about three times more than allowed in the benzene standard in order for veteran workers to qualify for medical surveillance.
In the arsenic standard, veteran workers were also included in medical surveillance. Under paragraph (n)(1)(i)(B) of the arsenic standard (29 CFR 1910.1018) all employees exposed above the action level for 30 or more days per year for a total of 10 years or more were covered by medical surveillance. Thus, OSHA considers the inclusion of medical surveillance for veteran workers, who have been exposed to cadmium for five years prior to the promulgation the new cadmium standard a reasonable basis to qualify them for medical surveillance.
Dr. Friberg stated in his written testimony (Ex. 29) that there are several reports of a high prevalence of kidney dysfunction observed after an exposure that would correspond to 45 years of exposure to 10 to 20 ug/m(3):
"...we should make clear that to equate such exposure with a safe threshold is to me a serious and irresponsible mistake.... a considerable prevalence of kidney dysfunction can be expected when below such concentrations... (Tr. 6/6/90, p. 76)"
The burden is on the employer to demonstrate that an employee previously or currently exposed to cadmium does not exceed any of the triggers in paragraph (l)(1)(i) of this standard and therefore need not be provided medical surveillance. OSHA believes the employer is in the best position to carry this burden. The employer has strong economic incentives to assure that medical surveillance is not provided to any employee who does not qualify for it. The employer also is best able to gather, develop, correlate and maintain the exposure data needed to assess an employee's current exposure and exposure history.
However, OSHA recognizes that it may be difficult at times for employers to sustain the burden of proof concerning employees who were exposed before the effective date of this standard. Nonetheless, where the extent of the employee's cumulative exposure is unclear, the Agency chooses to err on the side of protecting workers. Thus, if the employer is uncertain whether a particular employee has in fact been previously exposed at or above the action level for more than 60 months, and especially where the employer may have some reason to believe the employee may have been so exposed, it is OSHA's intention that the employer resolve doubts in favor of worker protection and to provide at least some medical surveillance for that employee. As a result, for example, OSHA intends that workers who were exposed for indeterminate, substantial periods prior to the effective date of this standard, and who were not regularly monitored, or for whom exposure records were not kept, be initially screened to detect potential or actual kidney disease or other cadmium-related illness. Thereafter, if medical surveillance carried out over approximately one year shows no indications of cadmium related disease or of increased risk of such disease, periodic medical surveillance for these veteran workers can be expeditiously terminated.
Paragraph (l)(1)(ii) of this standard requires that the employer provide the examination specified in paragraph (l)(6) to workers who are required to wear a respirator because their job exposes them to cadmium levels above the PEL,. The purpose of the examination is to determine the employee's capacity to wear a respirator. This requirement, which is typical of other OSHA health standards, (e.g., Lead, 29 CFR 1910.1025; Benzene, 29 CFR 1910.1028; Formaldehyde, 29 CFR 1910.1048; and Asbestos Final Standards, 29 CFR 1910.1001) is to assure the identification of employees with medical conditions that make wearing a respirator a health risk.
Paragraph (l)(1)(iii) provides that all medical examinations and procedures required by this standard be performed by or under the supervision of a licensed physician and without cost to the employee. The licensed physician is required to read and be familiar with the health effects section of Appendix A, the regulatory text of this section, the protocol in Appendix F, and the questionnaire of Appendix D. Although, a licensed physician is the appropriate person to supervise and evaluate a medical examination, certain required elements of the exam need not be performed directly by a physician and may be performed by another, appropriately qualified person under supervision of the physician.
OSHA received comments saying that medical examinations should be performed under physician supervision (Tr. 7/18/90, p. 160). The choice of the physician, and the physician's training, are extremely important factors in the medical evaluation of workers' health (Friberg, Tr. 6/6/90). For physicians who do not have a thorough knowledge of cadmium toxicology, preventing and treating cadmium induced disease can be very difficult (Ex. 29). Therefore, OSHA has provided documentation in the appendices to familiarize physicians and other medical personnel with the toxic effects of cadmium.
The standard also requires that all examinations and procedures be performed at a reasonable time and place. It is necessary that examinations and procedures be performed at a place convenient to the employee, during the workday, and without loss of pay, in order to maximize the likelihood that employees will participate. This provision is consistent with other OSHA health standards (e.g., Asbestos, 29 CFR 1910.1001; Arsenic, 29 CFR 1910.1018).
As mentioned above, paragraph (l)(1)(iv) requires that specimens for biological monitoring be collected and handled appropriately, and that laboratories be proficient, as specified in Appendix F.
Paragraph (l)(2)(i) requires the employer to provide an initial or preplacement medical examination to all employees covered by medical surveillance within 30 days after initial assignment to a job with exposure to cadmium or no later than 90 days after this standard goes into effect, whichever comes last. The purpose of the initial medical examination is to:
(1) Establish the current health status of the employee and to determine whether it is appropriate to assign the employee to jobs with cadmium exposure;
(2) Initially determine what level of medical surveillance the employer must provide to the particular employee; and
(3) Establish essential baseline data for each employee as a criterion for assessing subsequent changes in health status attributable to cadmium exposure.
The initial medical examination includes biological monitoring and a detailed medical and work history, with emphasis on past exposure to cadmium, history of organ system dysfunction relevant to cadmium exposure, and smoking history and status. OSHA has decided to rely on biological monitoring as the primary screening device for identifying employees at elevated risk of cadmium related illness. OSHA believes that biological monitoring results showing levels of cadmium in urine (CdU), Beta-2 microglobulin in urine (B(2)-M), and cadmium in blood (CdB), when used together, are the best indicators of cadmium exposure and of the risk of cadmium related illness (Dr. Friberg, Tr. 6/6/90, pp. 108-109).
OSHA has chosen to rely on these three biological parameters as the main medical screening device because they are the best indicators of present exposure, past exposure, and cadmium related kidney dysfunction. Generally, monitoring CdU levels is useful and needed to determine past exposure to cadmium and body burden of cadmium among workers without kidney disease. However, monitoring CdU levels is no longer reliable after the onset of disease because the kidney spills a large amount of cadmium. Then for a time no cadmium appears in the urine even though the kidney is damaged and the cadmium burden in the kidney cortex is continuing to increase (Friberg, Ex. 144-3-C).
Monitoring levels of CdB is generally useful as an indicator of recent exposure to cadmium. Elevated levels of B(2)-M are indicative of the presence or absence of an early stage kidney disease.
In choosing to rely primarily on biological monitoring for medical screening, OSHA has dropped the proposed requirement that a full medical examination be included as part of the initial medical examination, as provided in paragraph (l)(2) of the proposal (55 FR 4124). The Agency believes requiring biological monitoring of the indicators for cadmium exposure, cadmium body burden and cadmium induced kidney disease eliminates the need for a full medical examination as a screening tool. The biological indicators will be sufficient to establish the employee's baseline health status for all employees covered by medical surveillance. Given the adequacy of biological monitoring and the limited resources and the high cost of full medical examinations, the Agency believes that in the initial phase of medical surveillance, full medical examinations should only be required for employees whose biological monitoring results are abnormal as specified in paragraphs (l)(3)(i)-(iv).
Paragraph (l)(2)(iii) provides that an initial examination is not required if adequate records show that an employee has been examined in accordance with the requirements of paragraph (l)(2)(ii) within the past 12 months. This reflects a change from the proposal (55 FR 4124) in which no recent examination could be used instead of an initial examination. This provision was included because OSHA believes that requiring an initial examination so soon after an adequate prior examination is medically unnecessary and would waste scarce resources.
Paragraph (l)(3) specifies the main elements of the medical surveillance program the employer must provide to eligible employees. This program is basically incorporated in paragraph (l)(4), concerning periodic medical surveillance. The program, at first sight, may appear to be quite complex, but it is based upon a few simple, fundamental principles.
At least a minimum of medical surveillance must be provided to all workers covered under paragraph (l)(1)(i) of this standard. In addition, enhanced medical surveillance is required for workers whose initial biological monitoring results are abnormally high. At the outset, the frequency and scope of medical surveillance depends directly upon the level of initial biological monitoring results. Thereafter, it depends upon the results of any subsequent biological monitoring and medical examinations. These results, if abnormal, may increase the required frequency and scope of medical surveillance or, if within the "normal" range, may set the frequency and scope at minimum levels.
In the medical surveillance program required by paragraph (l) of this standard, an initial distinction is drawn between workers who are, or may be currently exposed by the employer on 30 or more days per year and workers who have been exposed by the employer prior to this standard for 60 months. For workers who have, or may have been excessively exposed prior to the effective date of this standard, the purpose of medical surveillance is twofold: first, to promptly identify those among them who have abnormal monitoring results, for whom further medical surveillance is required; and second to identify those among them who have biological monitoring results that are consistently within the "normal" range. Generally, employees in the latter group are not considered to be at excess risk of cadmium induced disease and, therefore, do not need further periodic medical surveillance. Thus, for workers in medical surveillance exclusively because of past exposure to cadmium, the results of initial and follow-up biological monitoring determine not only the frequency and scope of the ensuing medical surveillance but also whether the worker will continue to be provided with periodic medical surveillance at all.
Concerning currently exposed employees covered by medical surveillance under paragraph (l)(1)(i)(A), if an employee's initial biological monitoring results are confirmed to be within the range that for purposes of this standard is considered "normal", the employer must provide the employee with the minimum level of medical surveillance, as set forth in paragraph (l)(4)(i)-(iii) of this standard. However, if the employee's initial biological monitoring results are confirmed to exceed the normal range, then the employer must provide the enhanced level of medical surveillance that is appropriate to the level of the initial results, as set forth in paragraph (l)(3)(ii)-(iii). Basically, the higher the employee's monitoring results, the more frequent and comprehensive the medical surveillance required. A summary chart and Tables that outline these provisions have been provided in Appendix A.
Concerning employees whose exposure to cadmium has been, or may have been prior to the effective date of this standard, who are covered by medical surveillance exclusively under paragraph (l)(1)(i)(B), their biological monitoring results will determine whether or not they will be provided periodic medical surveillance. If the initial biological monitoring results are confirmed to be within the normal range, and if follow-up biological monitoring results required within 12 months under paragraph (l)(3)(i)(B) also are within the normal range, then under paragraph (l)(4)(v) periodic medical surveillance may be discontinued.
However: (l) if the initial biological monitoring results for such previously exposed employees are within the normal range, but their follow-up biological monitoring results, taken within 12 months, exceed the normal range, then the employer must provide annual medical examinations as specified under paragraph (l)(4)(v)(C) until all the results of biological monitoring are consistently within the normal range specified by paragraph (l)(3)(i)) or the examining physician determines in a written medical opinion that further medical surveillance is not needed to protect the employee's health. Or (2) if the initial biological monitoring results for such previously exposed employees exceeds the normal range, then these employees shall be provided medical surveillance under the same regimen as currently exposed employees [(l)(3)(ii)-(iv)] unless and until the employee's levels of CdU, CdB, and B(2)-M are all within the normal range on two consecutive tests over a period of no less than 12 months. At that point, as specified by paragraph (l)(4)(v)(B), the employer may terminate periodic medical surveillance for the employee.
In establishing this medical surveillance program, OSHA had to make a number of fundamental determinations. First, the Agency had to decide which biological parameters would be used to detect excess cadmium exposure and potential excess risk of cadmium induced disease. Second, OSHA had to assess the range that for the purposes of this standard will be considered to be the "normal" range for each of these parameters. Third, the Agency had to decide how to trigger enhanced medical surveillance. Fourth, OSHA had to decide when and how often to require biological monitoring, full medical examinations, and other related actions to be provided by the employer. Fifth, OSHA had to decide how the medical surveillance program should be applied to employees previously exposed to cadmium who no longer are exposed. Sixth, the Agency had to decide at what levels of the biological parameters, if any, workers need to be removed from exposure to cadmium at or above the action level and at what levels, if any, these workers could be returned to their normal cadmium exposed jobs. All of these decisions are based upon the health effects data in the record, including epidemiological and animal studies of cadmium induced disease and histopathological data, which are thoroughly summarized and analyzed in the Health Effects section of this preamble (Section V).
Concerning the choice of biological parameters, it is universally recognized that the best measures of cadmium exposure are measurements of cadmium in biological fluids, especially urine and blood. Of the two, CdU is conventionally used to determine body burden of cadmium in workers without kidney disease. CdB is conventionally used to monitor for recent exposure to cadmium. In addition, levels of CdU and CdB historically have been used by industry as triggers that require medical action (Ex. 14-6) and to evaluate the likelihood that workers will develop kidney disease (Thun et al., Ex. L-140-50; WHO, Ex. 8-674; ACGIH, Exs. 8-667; L-140-51).
The third biological parameter upon which OSHA relies for medical surveillance is Beta 2 microglobulin in urine (B(2)-M), a low molecular weight protein. Excess B(2)-M has been widely accepted by physicians, scientists, and industry experts, as a reliable indicator of functional damage to the proximal tubule of the kidney (Exs. 8-447; 144-3-C; 4-47; L-140-45; 19-43-A). Excess B(2)-M is found when proximal tubules can no longer reabsorb this protein and essential elements in a normal manner. Given the fact that the employees monitored for B(2)-M levels under this standard are in fact exposed to not inconsiderable amounts of cadmium, abnormal B(2)-M levels in these employees are more likely to be related to excessive cadmium exposure than to other causes. (See Section V, Health Effects). Age alone cannot account for the excess of B(2)-M observed in cadmium-exposed workers (Exs. 8-642; 8-068-B; L-140-45). Used in conjunction with biological test results that indicate the presence of abnormally high levels of CdU and CdB, the finding of excess B(2)-M can establish for an examining physician that any existing tubular proteinuria is probably cadmium-related (Tr. 6/6/90, pp. 108-109, 135).
OSHA chose to rely on B(2)-M as an early indicator of kidney disease because the Agency concluded that B(2)-M is the most thoroughly studied of the various indicators that might be used. Although there may be some problems associated with handling B(2)-M (e.g., the pH of the urine must be kept at or above 6.0; Exs. 8-086; 8-447; L-140-1); and with accurately measuring and characterizing the protein in the sample (Phadebas, Ex. L-140-1), most occupational, epidemiological studies of kidney disease among cadmium exposed workers have relied upon B(2)-M measurements as the early marker of nephrotoxicity (Exs. 8-086; L-140-1; 4-47; 4-28; 4-27; L-140-45; L-140-50). Moreover, with few exceptions, the medical experts who testified at the OSHA hearings and provided comments in the cadmium rulemaking agreed that, all things considered, B(2)-M currently is the best single, non-invasive test for screening for cadmium induced nephrotoxicity (Exs. 19-14; 55; 4-47; 4-28; 4-27; L-140-50; 8-670).
OSHA specifically considered alternative markers, such as retinol binding protein (RBP), metallothionein, and N-acetyl d glucosaminidase (NAG) in urine, and decided that experience with these alternatives was too limited and their biological significance and predictive value was less certain than B(2)-M (Ex. 30). For example, "normal" levels for retinol binding protein were not clearly established in the record and do not appear to have been clearly established in the general medical literature. (See NIOSH, HHE Ex. 128; Mason, Ex. 8-669-A; Health Effects, Section V - kidney.) Having chosen the biological parameters to be measured, OSHA then had to evaluate the record evidence to determine background levels of each parameter so that the Agency could determine what levels should be considered excessive. With regard to CdU, very low levels of cadmium are found in body fluids of non-occupationally exposed general populations, even though cadmium occurs in the general environment and can be taken into the body through the consumption of cadmium-containing food or by smoking cigarettes. It has been shown that urinary concentrations of cadmium minimally increase with age (Exs. 8-642; 8-86A).
In 1983, Kowal and Zirkes reported the concentration of CdU samples collected from almost 1,000 persons (males and females, CdU standardized to specific gravity) from nine states in the U.S. (Ex. 8-642). Ninety-five percent of the population had CdU levels less than 2.8 ug/g Cr, which is lower than the cadmium in urine trigger in this standard for enhanced medical surveillance. The overall geometric mean level of CdU for males was 0.55 ug/g Cr and for females was 0.78 ug/g Cr (Ex. 8-642). In other studies, median levels of CdU are about 0.5 to 1 ug/liter at the age of 70 (Exs. 8-068-B, L-140-31).
It was observed that the urinary excretion of cadmium was also influenced by smoking habits. Smokers have higher average levels of CdU compared to non-smokers of the same age, (Ex. 8-86-B) but CdU levels are not influenced by smoking to the same extent as cadmium blood levels. In a limited study of CdU levels among the U.S. population, among current and former smokers, arithmetic mean CdU levels ranged from 1.0 to 1.5 ug/l urine for females and males, respectively (Ex. 8-86-B). While this study indicated some smokers could have CdU levels of 3.4 ug/liter urine, this is an upper range that has not been standardized to control for diuresis, i.e., standardized to grams of creatinine.
These levels are generally lower than the lowest CdU trigger levels included in the proposed cadmium standard (55 FR 4125, Feb. 6, 1990).
Several industry spokespersons held the opinion that a trigger level of 10 u/g Cr urine (or 10 ug/l urine) would protect workers from unnecessary risk of cadmium-associated renal dysfunction (Exs. 19-30; 19-43; 8-201; 19-43; 120). However, as discussed below and in detail elsewhere in the preamble, OSHA's understanding of the relevant literature and risk assessments indicates that this is incorrect (Exs. 8-447; 19-14).
Dr. Tyner, Medical Director of Gates Energy Products, a major nickel-cadmium battery production facility, indicated that 10 ug/g Cr in the urine would be a practical and safe trigger for medical action (Ex. 19-2). Dr. Kazantzis who testified for the Cadmium Council stated that levels must be kept much lower than 10 ug Cd/g Cr (Tr. 6/8/90, pp. 150-200; Ex. 19-43-A).
The Cadmium Council submitted comments in support of medical action whenever CdU levels reach 10 ug/g Cr (Ex. 19-43) based on a study by Buchet et al. in 1980 (Ex. 8-201). However, OSHA notes that in the study by Buchet, the prevalence of kidney dysfunction among exposed workers whose CdU levels were above 10 ug Cd/g Cr was 15% (Ex. 8-201). In the total group, the prevalence of kidney dysfunction among exposed workers (18.2%) was statistically significantly elevated (p < 0.025) above the prevalence of kidney dysfunction among controls (6.8%) Richard Bidstrup, Counsel for SCM Chemicals, Inc., submitted comments on SCM's behalf (Ex. 19-42A) to the effect that measuring the level of CdU is helpful and that if urinary cadmium is greater than 10 ug/l (with specific gravity adjusted to 1.020) or low molecular weight protein is greater than 300 ug/l, urine analysis should be conducted more often until levels are below these thresholds.
Leading world experts in the field of cadmium-induced kidney dysfunction, such as Drs. Thun, Friberg, and Elinder, were of the opinion that CdU levels had to be kept as far below 10 ug Cd/g Cr as possible in order to protect most workers from kidney dysfunction. Their opinions were based upon their own studies and their review of the medical literature (Ex. L-140-50).
In 1991, the American Conference of Governmental Industrial Hygienists (ACGIH) recommended lowering its biological exposures index (BEI) for CdU to 5 ug Cd/g Cr (L-140-51).
After testifying at the hearings and in response to a written request by OSHA for further information and comments on medical surveillance, David Volkman, of Big River Zinc, stated (Ex. 84) that medical surveillance monitoring should focus on micrograms of cadmium per gram creatinine (ug Cd/g Cr) and B(2)-M. He stated that if a trigger level was set for medical action, 5 ug Cd/g Cr would be adequate (Ex. 46).
Dr. Bosken, a physician who provided comments for the Public Citizen Health Research Group and the International Chemical Worker's Union (HRG/ICWU), stated that HRG/ICWU supports a lower level of urinary cadmium (3 ug/g Cr) than that proposed by OSHA as the level to initiate a review of the employee's work practices, respirator use, and engineering controls (Ex. 123). The HRG/ICWU support 5 ug/g Cr as a trigger level for medical removal, noting that, at this level, "...a substantial amount of renal disease [is] to be expected in workers....(Ex. 123)". Thus, in summary, despite some differences in opinions, there is broad that CdU levels must be well below 10 ug/g Cr. In addition, broad-based population studies show that CdU concentrations for the general population not occupationally exposed to cadmium average less than 1 ug/L and that 95 percent of individuals not occupationally exposed, including both smokers and non-smokers, exhibit levels of CdU less than 3 ug/g Cr. (See Appendix F).
OSHA, therefore, chose the level of CdU > 3 ug Cd/g Cr as its lowest CdU trigger for enhancing medical surveillance. That level represents a clear cutoff point above which it may be assumed that workplace exposure to cadmium is affecting the biological monitoring test result. Dr. Elinder testified that while the medical surveillance protocol for cadmium workers suggested by OSHA is more strict in comparison to the current Swedish protocol, it is better (Ex. 55). As Dr. Elinder stated in his testimony, dose-response analyses in the medical literature makes it clear that if CdU is allowed to increase above 5 ug/l about five percent of workers are likely to get cadmium induced tubular dysfunction.
In contrast to CdU levels, levels of cadmium in blood (CdB) reflect recent exposure to cadmium and do not appear to be significantly affected by the onset of kidney damage. Cadmium levels in blood are affected to some small degree by age, diet, and sex and to a larger degree by smoking habits (Jarup et al., Ex. 8-661). In studies of occupationally exposed workers it was found that age is not an important confounder (Ex. 8-661) In 1988, Drs. Friberg and Elinder evaluated median CdB levels in males and females in different smoking categories. Ninety percent of female and male non-smokers had CdB levels less than 0.5 and 0.3 ug/liter whole blood (lwb), respectively. Ninety percent of female and male former-smokers had CdB levels below 0.8 and 0.9, respectively. Current smokers were divided into categories based upon the number of cigarettes smoked daily. Ninety percent of females and males who smoked less than a pack a day had CdB levels less than 2.0 and 2.5, respectively, while 90 percent of females and males who smoked more than half but less than a pack a day had CdB levels less than 3.0 and 3.7, respectively. Among female and male smokers who smoked more than a pack a day, 90 percent had CdB levels less than 3.5 and 4.5, respectively (Ex. 8-740).
A number of other studies provide data on the CdB concentration of non-occupationally exposed persons and indicate that non-smokers in countries where dietary cadmium intake is 10 to 20 ug/day have a median concentration in whole blood in the order of 0.4 to 1.0 ug/l, whereas smokers have a median concentration of 1.4 to 4.5 ug/l (Ex. 8-086-B). In the U.S.A. mean levels of CdB of non-smokers ranged from 0.4 ug Cd/lwb to 0.8 ug Cd/lwb. Mean levels of CdB among U.S. smokers were 0.9 in former smokers and ranged from 1.0 ug Cd/lwb to 3.4 ug Cd/lwb in current smokers (Ex. 8-086-B).
In 1980, for example, the World Health Organization, United Nations Environment Program (WHO/UNEP) launched a global biological monitoring program for the assessment of human exposure to heavy metals. Ten cities were included in the program. The program was initiated to enable valid comparisons of CdB levels for different countries. Until then, there were no accurate studies available and the normal concentration of CdB was not yet known (Ex. 8-86-B). In the WHO program, blood samples were obtained from similar groups of teacher-volunteers in cities from each participating country, including Baltimore, the only U.S. city for which such data were available. Different analytical techniques were used in different countries. Volunteers were divided into smokers and non-smokers.
In Baltimore, according to the WHO/UNEP study, the upper 90th percentile of CdB levels for non-smokers was about 1.0 ug Cd/lwb while the upper 90th percentile of CdB levels of smokers was about 2.6 ug Cd/lwb. A very high level of CdB was observed among smokers in Mexico City, i.e., the upper 90th percentile of CdB levels of smokers was 8 ug/l. However, the tobacco products, smoking habits of individuals, and environmental pollution problems in Mexico City are not readily comparable with those in Baltimore (Ex. 8-86-B).
In the final cadmium standard, OSHA has established a "normal" level of cadmium in blood as levels below 5 ug/lwb. This is based on OSHA's review of studies in which 95 percent of non-occupationally exposed worker populations which included both smokers and non-smokers exhibited CdB levels below 5 ug/lwb. (See Appendix F.) By contrast, in studies that provided sufficient data on CdB levels among occupationally exposed workers who had greater than nominal levels of cadmium exposure, 95 percent of workers had CdB levels greater than 5 ug/lwb. (See Health Effects Section; Appendix F.) Several industry spokespersons held the opinion that a trigger level of 10 ug/lwb would protect workers from unnecessary risk of cadmium-associated renal dysfunction (Exs. 19-30; 19-43; 8-201; 19-43; 120). However, other participants in the rulemaking held the belief that 10 ug Cd/lwb is too high.
In 1991, the ACGIH recommended lowering its biological exposures indices (BEI) from 10 ug/lwb to 5 ug Cd/lwb (L-140-51). ACGIH justified this lowering of the BEI for CdB in its Notice of Intended Changes (Ex. L-140-51). ACGIH stated that recent studies indicate a higher incidence of renal dysfunction than previously estimated among workers with cumulative CdB concentration below 10 ug/lwb. The new BEI is intended to prevent the potential for increased urinary excretion of markers of renal dysfunction in almost all workers.
Dr. Elinder stated that from the dose-response analysis presented by Jarup, 1988, it is clear that if cadmium exposure continues, producing a cadmium concentration in workers' blood exceeding five micrograms per liter, a small percentage of the exposed workers will develop B(2)-microglobulinuria (Ex. 55).
In summary, OSHA chose greater than 5 ug/lwb as the lowest CdB trigger for enhancing medical surveillance, because that level represents a clear cutoff point between exposed and non-exposed population. (See Appendix F.) OSHA received many comments regarding the use of B(2)-M as a marker of kidney function. Dr. Lauwerys, the author of several studies on cadmium-induced renal effects and the guide for physicians, Health Maintenance of Workers Exposed to Cadmium published by the Cadmium Council (Ex. 8-447), stated that B(2)-microglobulinuria occurs if levels of B(2)-M exceed 200 - 300 ug/gram creatinine (g Cr) (Ex. 8-447). Other world experts who testified during the hearings agreed with the normal levels given by Dr. Lauwerys, standardized to grams of creatinine (g Cr) to correct for diuresis. Dr. Goyer testified that in the general population normal levels of B(2)-M are less than 300 u/g Cr (Tr. 6/6/90, p. 135). Dr. Friberg testified that levels of B(2)-M above 200 ug/g Cr are rare in a population with "normal" kidney function (Ex. 144-3-C).
Although individual variations are great, most people's levels, are very low. Kowal et al. (Ex. 8-642) evaluated the levels of B(2)-M in 1,000 non-occupationally exposed populations in the United States. The average level in the oldest group studied, aged over 70 years was 107 ug B(2)-M/l urine. This was only marginally higher than in the age group 20 - 70, in which the average levels were 69 to 84 ug B(2)-M/l urine (Referenced in Ex. 8-068-B).
Dr. Elinder, chairman of the Department of Nephrology at the Karolinska Institute, testified that the normal concentration of B(2)-M has been well documented (Evrin and Wibell, 1972; Kjellstrom et al, 1977a; Elinder et al, 1978, 1983; Buchet et al, 1980; Jawaid et al, 1983; Kowal and Zirkes, 1983 referenced in Elinder, Ex. L-140-45). Elinder stated that the upper 95 or 97.5 percentile for the urinary excretion of B(2)-M among persons without tubular dysfunction is below 300 ug/g Cr (Kjellstrom et al, 1977a; Buchet et al, 1980; Kowal and Zirkes, 1983]. Elinder defined levels of B(2)-M above 300 ug/g Cr as "slight" proteinuria (Ex. L-140-45).
According to Kjellstrom (Ex. 4-47), the upper 95 percent tolerance limit reported in his paper (290 ug/l urine) was considered to be representative for large groups of subjects. According to Falck, the values obtained from the controls in his study were close to the levels that would be expected from unexposed people (Falck, Ex. 4-28). In the Falck study, normal kidney function was thus established at B(2)-M less than 400 ug/l urine for 24 hour samples.
In six of the seven major epidemiological studies reviewed by OSHA in Section V - Health Effects, B(2)-M was the marker of kidney dysfunction chosen by the authors. The "normal" levels of B(2)-M was established based on samples taken from non-exposed controls and was about 300 ug/g Cr or less in all but two of the seven studies (Thun, Ex. 8-670; Falck, Ex. 4-28). (See Section VI - Quantitative Risk Assessment). In the two studies cited by the Cadmium Council, Buchet regarded B(2)-M levels greater than 200 ug/g Cr as abnormal and Toffoletto regarded B(2)-M levels greater than 260 ug/l urine as abnormal (Exs. 19-43-A, 8-201).
Furthermore, in studies of exposed workers, the geometric mean levels of B(2)-M among workers without renal dysfunction, including both smokers and non-smokers, were lower than 295 ug/g Cr (Kjellstrom, Ex. 4-47; Roels et al., 1991, Ex. 149; Miksche et al., 1981, Ex. 12-10-E; and Thun, Ex. 8-670; see also Appendix F). The fact that there is no clear statistical cutoff point between occupationally exposed and non-exposed individuals should not be surprising. Significantly elevated B(2)-M levels are expected to correspond to the onset of kidney dysfunction. Only a certain number of cadmium exposed workers in the medical literature are likely to have developed kidney dysfunction, and this is likely to occur primarily among workers with high past exposures to cadmium. Consequently, the range of levels of B(2)-M observed in most of occupationally exposed individuals are likely to be similar to the "normal" range observed among the unexposed. Despite the absence of a clear cutoff point between cadmium-exposed workers and non-exposed populations, such as with CdU and CdB, the range of levels of B(2)-M that is considered abnormal is rather well established and generally agreed upon (Exs. 144-3-C, L-140-45).
The Agency recognizes that, although biological values lie on a single continuum with an infinite number of points between health and illness (Exs. 19-2; 19-14; 19-33; 19-34; 19-40; 19-42; 19-43; 77; 82; 84; 101; 106; 107; 120; and 123), OSHA had to select particular levels to indicate greater and lesser risk of cadmium-induced renal disease and to trigger appropriate medical responses. OSHA believes that its choice of triggers for enhanced medical surveillance based upon B(2)-M levels represent cutpoints that are well established in the medical literature and widely used in practice.
Three issues were raised during the rulemaking regarding the use of B(2)-M as a marker of kidney dysfunction and material impairment. First, there are other causes of elevated levels of B(2)-M, not related to cadmium exposures (Ex. 19-14), and there are factors that can cause B(2)-M to degrade so that low levels might be found even in workers with tubular dysfunction. For example, regarding the degradation of B(2)-M, workers with acidic urine with pH < 6 (Exs. L-140-1, 8-447) might have B(2)-M levels that are within the "normal" range, when in fact, kidney dysfunction has occurred (Ex. 8-86-B; Friberg, Tr. 6/6/90, pp. 108-109). Second, there is debate over the pathological significance of proteinuria. Finally, detection of B(2)-M at low levels is considered by some to be difficult. The issue of the levels of detection of B(2)-M and proper handling of urine samples to prevent degradation of B(2)-M has been addressed under "Specimen collection and preparation" procedures developed by Phadebas (Ex. L-140-1) and has also been addressed by OSHA in the section on specimen handling and lab standardization (See Appendix F).
Regarding the first issue, the specificity of B(2)-M as a marker of cadmium-induced kidney dysfunction is well established. The only other renal toxins or medical conditions which lead to elevated levels of B(2)-M are anti-cancer drugs, aminoglycosides (antibacterial antibiotics such as streptomycin), anti-inflammatory compounds, myeloma, flu, and upper respiratory infections (Dr. Friberg, Tr. 6/6/90, pp. 108-109; Ex. L-140-1). As Dr. Thun stated:
"Low molecular weight proteinuria....does occur from other conditions but it's uncommon....part of the reason why the (kidney) data are so consistent is that the studies use a rather specific marker of cadmium renal effects...."(Tr. 6/7/90, p. 174)"
Given the specificity of B(2)-M, it is unlikely that other renal toxins would result in elevated levels of B(2)-M (Exs. 4-47; 4-28; 4-27; L-140-50; and 8-670).
While a limited number of other non-cadmium related illnesses or factors may result in elevated B(2)-M levels (Ex. 29), OSHA allows physician discretion as to the type of actions that must be taken when levels of B(2)-M are only slightly elevated. For example, under paragraphs (l)(3)(ii)-(iv), physicians must provide a medical examination within 90 days if biological test results are "abnormal". This allows the physician time to evaluate and to rule out other etiologies. Moreover, medical removal for elevated levels of B(2)-M is mandatory only when B(2)-M is significantly elevated and either CdU or CdB also is elevated, specifically indicating excess cadmium exposure. B(2)-M can also be degraded by bacterial infections, and in urine with pH less than 6, levels of B(2)-M decrease. Bacterial infections and low pH levels occur normally in a proportion of the population. B(2)-M can be degraded by low pH and bacterial infections while the B(2)-M is stored in the bladder or urinary tract, and while urine is stored in sample collection bottles, leading to measured concentrations which are erroneously low (Ex. 8-086-B).
However, the bacterial infections are often accompanied by symptoms which can be diagnosed and treated. The acidity of the urine can be corrected in vivo by consumption of sodium bicarbonate and can be raised in the urine collection bottle by addition of an alkaline buffer. (See Ex. L-140-1, and Appendix F.) Regarding the remaining issue, pathological significance, it is clear from the testimony of world experts that elevated levels of B(2)-M should be considered to be material impairment. Dr. Friberg testified that:
"....the beta-2 microglobulin proteinuria....should be regarded as an adverse effect......predictive of an exacerbation of the age related decline of the glomerular filtration rate.......the proteinuria in cadmium poisoning is irreversible and is predictive of more severe effects even if the worker is removed from further cadmium exposure.......It is true that an increased excretion of low molecular weight proteins can be a very early indicator of kidney dysfunction. That's not immediately of the same clinical importance as an overt renal disease. Nevertheless, it is irreversible and the beginning of a process which has a high probability to lead to a progressive disease, a decrease in the glomerular filtration rate which clearly is a serious effect that easily may lead to overt disease. When discussing the kidney damage from cadmium, it is important that we make it clear that we are talking about serious, but often insidious effects on vital organs. The kidney has a considerable reserve capacity but once this is consumed symptoms may appear in swift succession and the condition of the patient then deteriorates rapidly, and the infection or other, in itself trivial disorder, could be a triggering mechanism. It is our responsibility to prevent this situation even among a small proportion of workers." (Tr. 6/6/90, pp. 73, 82, 86)
When increased excretion of proteins found (...B(2)-microglobulinuria exceeding 200-300 ug/g Cr) and confirmed by a subsequent examination a few weeks later, it is recommended to perform a more extensive investigation of kidney function for evaluating the intensity of the biological disturbance ... Although the discovery of significantly increased excretion of proteins does not necessarily mean that renal insufficiency will occur, it is wise to remove definitively from cadmium exposure workers presenting any persistent signs of renal dysfunction" (Ex. 8-447).
Prolonged exposure to cadmium may lead to glomerular proteinuria, glucosuria, aminoaciduria, phosphaturia, and hypercalciuria (Exs; 8-86-B; 4-28; 14-18, p. 157) and kidney stones (Tr. 6/6/90, p. 106). These conditions are indicated by excess urinary amino acids, glucose, phosphate, or calcium, respectively. Each of these elements are essential to life, and under normal conditions their excretion is regulated by the kidney. Once low molecular weight proteinuria has developed, however, these elements may dissipate from the body. Loss of glomerular function may also occur, indicated by a decrease in the glomerular filtration rate and an increase in serum creatinine. Severe cadmium-induced renal damage may develop into chronic renal failure and uremia at which point some form of dialysis or kidney operation will be needed (Ex. 55).
Kidney dysfunction persists for years even after cessation of exposure. Loss of calcium and phosphorus may contribute to the increased risk of kidney stones observed in cadmium exposed workers (Ex. 4-29). Dr. Friberg testified that, in his opinion, kidney stones are a serious sequelae to cadmium-induced renal dysfunction. He and others originally thought that the increased prevalence of kidney stones observed in his studies of cadmium-exposed workers was confined to Sweden (Ex. 29). But later, the increased prevalence of kidney stones was observed in England, and in the U.S. the presence of kidney stones is a sign of a more generalized disorder of the mineral metabolism in the kidney (Tr. 6/6/90, p. 106).
Others held a different opinion about the prevalence of kidney stones among cadmium-exposed workers. For example, Dr. Spang stated that kidney stones are common in the general population of Sweden (20% in men and about 5% in women), and although he observed cases of kidney stones among cadmium-exposed workers, he did not know if the prevalence was different from that of the general population (Exs. 80 and 81).
Cadmium may also precipitate clinical osteopathy in persons with inadequate dietary calcium intake (Ex. L-140-50). Diets low in vitamin D and calcium may be a contributing factor to sequelae subsequent to cadmium-induced renal dysfunction.
There are at least two hypothesized scenarios by which cadmium-induced tubular proteinuria can cause other adverse health effects (Ex. 8-086). Under the first of these, cadmium-associated tubular dysfunction causes damage to the production of biologically active metabolites such as vitamin D which occurs primarily in the kidney. Under the second scenario, cadmium may cause atrophy of the gastrointestinal tract thereby reducing its ability to absorb essential elements such as calcium and phosphates. Both would lead to loss of essential elements and poor absorption of other minerals to replace those lost.
The gravity of cadmium-induced renal damage is compounded by the fact that there is no simple medical treatment such as chelation to prevent or reduce the accumulation of cadmium in the kidney without substantial risk (Tr. 6/6/90; p. 105). In contrast to other heavy metals, current chelation therapy does not reduce the body burden of cadmium without producing significant renal damage. When chelated cadmium arrives in the kidneys where the cadmium may still be toxic to renal cells. Thus, large amounts of cadmium may move from the liver or muscle storage sites, overwhelm the kidney's usual attempts to store cadmium in a less toxic form, and accelerate deterioration of renal function.
Regarding the pathological significance of proteinuria, OSHA believes that the loss of function of the proximal tubules with tubular proteinuria, as indicated by elevated levels of B(2)-M, itself signifies damage that constitutes material impairment of health. OSHA acknowledges that the significance of the dysfunction as evidenced by elevated levels of B(2)-M is controversial. Part of this controversy arises from the fact that a worker with elevated levels of B(2)-M may not experience any symptoms.
Dr. Goyer testified that the confusion over the interpretation of pathological significance of elevated levels of B(2)-M stems from the fact that injury to the tubuli ultimately affects the functioning of the glomerulus. According to Dr. Goyer, the confusion lies in part in the fact that cadmium's earliest effect is primarily in the tubule, while kidney function is usually measured in the glomerulus (Tr. 6/6/90, pp. 126-127).
OSHA believes that this confusion results from two misunderstandings. First, tubular proteinuria measured in micrograms per gram creatinine (ug/g Cr). Total proteins are measured in milligrams per gram creatinine in urine. Measuring total proteins is not useful for measuring the presence of tubular proteinuria. As Dr. Lauwerys stated in his guide to physicians:
"When increased excretion of protein is found (total protein exceeding 250-350 mg/g creatinine, or beta 2 microglobulinuria exceeding 200-300 ug/g creatinine)...it is recommended to perform a more extensive investigation of kidney function for evaluating the intensity of the biological disturbances.... (Ex. 8-447)."
Cadmium-related tubular damage usually precedes other kidney damage, but cadmium can cause other types of kidney damage, e.g., glomerular damage, at the same time as tubular damage (Ex. 4-50; Ex. 55). Once tubular proteinuria has developed, there is a greater likelihood that further damage to the kidney will result.
Second, leading world experts on cadmium-associated kidney dysfunction have stated that workers with tubular proteinuria will have a portion of the kidney's functional capacity compromised. This may not at first be manifested as "symptoms," because the kidney has a certain amount of functional reserve. However, the remaining functional portion of the kidney is needed at various times throughout one's life to deal with conditions or other illnesses that are likely to occur. If this reserve is reduced the remaining functional capacity of the kidney may rapidly succumb to a number of otherwise benign conditions. According to Dr. Elinder, Chairman of the Department of Nephrology at the Karolinska Institute in Stockholm, Sweden, workers with tubular proteinuria frequently deteriorate, with a significant decrease in renal function. Occasionally, severe cadmium-induced renal damage has progressed to become chronic renal failure and uremia (Ex. 55). At very low levels of B(2)-M, however, a physician can determine that damage is occurring before it is "overt" illness that results in severe symptoms.
According to Dr. Goyer, Chairperson of the World Health Organization's Task Force on Cadmium, in his testimony at OSHA's hearing, fifty percent of workers with elevated levels of beta-2 microglobulin between 500-1,000 ug/g Cr will never revert to normal kidney function (Ex. 30). According to Dr. Friberg, Professor Emeritus, Karolinska Institute, this is because the tubules contain lesions that can be observed in histopathology examinations (Ex. 29).
While most physicians would agree that glomerular effects and loss of GFR must be taken more seriously than a slight elevation in B(2)-M, the finding of elevated levels of low molecular weight protein in the urine by itself indicates kidney dysfunction in the tubule (Ex. 8-447).
As Dr. Friberg stated in his testimony, each part of the nephron is dependent on every other part of the nephron. It is his expectation that if one part of the nephron suffers damage it is more likely that another part will suffer damage (Tr. 6/6/90, pp. 107-108). Ultimately then, cadmium-related tubular effects will be manifested as an effect on the function of the glomeruli, either subsequently to or in association with the onset of tubular proteinuria.
Because of the functional reserve of the kidney, the adaptive increase in a single nephron's glomerular filtration rate, after total or partial loss of other damaged nephrons, tends to obscure injury until a considerable amount of the functional elements of the kidney, the parenchyma, is irreversibly lost. This implies that under normal conditions, the basal GFR is submaximal. If as has been suggested, glomerular balance is very tightly maintained, reduction of tubular function may have repercussions on the glomerular level (Ex. 149). Early changes in glomerular function are not necessarily detectable by the measurement of basal GFR, but such changes may have a significant impact on health (Ex. 149). In a study by Roels (Ex. 149) it was found that a renal cadmium burden that had not yet caused microproteinuria did not impair the filtration reserve capacity of the kidney, but the age related decline of the baseline and maximal GFR is exacerbated in the presence of cadmium induced microproteinuria.
Not all participants in the rulemaking agreed that elevated levels of B(2)-M signified damage that constitutes material impairment of health. Mr. Ken Storm, Senior Industrial Hygiene Specialist with Monsanto, stated that tubular proteinuria may result from a biochemical lesion of no clinical significance (Ex. 19-14).
"....no histological abnormalities [are] seen in the proximal tubules...when there has been modest increase in urinary B2MG and Cd....(people with)....mild to moderate increases in urinary B2MG and Cd do not progress to renal failure if there are no other causes present such as infection, diabetes, etc. (Ex. 77)"
Dr. Kazantzis testified that in his opinion, tubular proteinuria alone is not accompanied by any specific histological change and that its pathological significance is unclear. Dr. Friberg, however, stated:
"It should be emphasized that tubular proteinuria may be accompanied by specific histological changes. Sometimes such changes have been reported before the functional changes. There are abundant data from animal studies showing early histological changes (Ref. by Kjellstrom, 1986, p. 38-43). Experiments from humans are more limited as only a small number of autopsies or biopsies are available. To the extent available, histologic changes were seen first of all in the proximal tubules (Ref. by Kjellstrom, 1986, p. 50-53)." (Ex. 29).
Morphological changes are those that pertain to the form or structure of the organ. Histological changes are those that pertain to the minute structure and composition of the organ tissue. Twenty-three workers were evaluated for whom autopsy or biopsy data on morphological changes in the kidney were available (referenced in Dr. Friberg's written testimony). Of these, 18 workers had proteinuria. Of the 18 workers with proteinuria, all but three had morphological changes in their kidneys. There were no cases of workers with morphological changes without proteinuria (Ex. 144-3, p. 53). In five of the autopsy reports, the morphological changes in the kidneys were mainly confined to the proximal tubules, whereas the glomeruli were less affected.
These results demonstrate that functional changes in the kidney can occur before the microscopic structure of the kidney is severely damaged. The human data on pathological changes are limited, however, and animal data show that in some studies, morphological changes in the tubules emerge before measurable proteinuria (Ex. 8-086). In the absence of a better test, however, it appears that the use of proteinuria as a screening tool for morphological changes in the kidney will identify all cases of workers with histological or morphological changes in kidney tissue as well as identifying those with only functional changes that affect the kidney's ability to filter (Ex. 8-086 B).
These results show that elevated levels of B(2)-M may indicate that kidney lesions of clinical significance have already occurred (Ex. 19-14). While a worker with elevated levels of B(2)-M may not manifest any overt symptoms of illness, nonetheless, the tubuli and glomeruli have lesions that compromise the functioning of the kidney as a filtration mechanism. Any other minor kidney trauma may progress rapidly to serious kidney damage.
According to the American Conference of Governmental Industrial Hygienists (ACGIH):
"Persons excreting 290 ug/L B(2)-microglobulin are not disabled; indeed they will not experience any symptoms. However, the lesion (from tubular proteinuria) is irreversible and represents a permanent loss of functional reserve. An infection or other condition which compromises renal function, but which would not normally lead to serious illness, could overwhelm the remaining kidney capacity. (Ex. 8-644)"
While Dr. Kazantzis testified that renal stone formation has been rare in cadmium workers in recent years (Ex. 19-43A), and he went on to say that in a:
"......small proportion of long-term heavily exposed cadmium workers, tubular proteinuria has been followed by renal glycosuria, abnormal aminoaciduria, phosphaturia, and hypercalcuria. (Exs. 80 and 81)"
Dr. Kazantzis continued that progressive decline in renal function is a slow process in workers with cadmium-induced nephropathy and that this decline is unlikely to progress to an increased mortality from chronic renal disease. In support of his opinion, he cited his study (Kazantzis and Armstrong 1982; Ex. 8-603) in which approximately 7000 cadmium-exposed workers with more than one year of cadmium exposure between 1942 and 1970 were followed up to 1979 (Ex. 8-684). He found an SMR of 65 for all deaths coded as nephritis and nephrosis; the five year update showed an SMR of 85. One worker classified as being in the "ever high" exposure subgroup died from nephritis and nephrosis.
Dr. Elinder indicated, however, that most workers in Dr. Kazantzis' study had such low cadmium exposures that cadmium-associated illnesses would not be induced (Ex. 4-25). By combining 199 workers with high exposures into a group with over 6000 workers with low exposures into one group, the power of the study to find an effect was reduced. Increased mortality from chronic nephritis and nephrosis has been observed in Swedish battery workers (Exs. 4-68 and 8-740). The difference between expected and observed deaths in the Kazantzis study may well be due to local differences in recording certain types of information on death certificates.
Three other epidemiological studies of cadmium exposed workers have shown increased mortality from kidney diseases, genito-urinary tract diseases, or kidney cancer. Thun observed an elevated SMR for genito-urinary cancer (SMR=135, Obs=6) in his total cohort (Ex.4-67); Dr. Elinder (Ex.4-25) reported an elevated SMR for genito-urinary diseases in his total cohort (SMR=300, Obs=3.0); and Holden et al. (Ex.4-39) observed an elevated SMR for genito-urinary cancer in his total cohort (SMR=122, Obs=4.0). Because the number of excess cases in each study is too small to make these findings statistically meaningful, the relationship between cadmium exposure and risk of death from kidney dysfunction is not clear. These three mortality studies, however, provide consistent evidence of excesses of kidney illnesses among cadmium-exposed workers. This suggests the possibility that, at least in some cases, cadmium-induced kidney dysfunction may be associated with excess death.
Death from nephritis, nephrosis or end-stage renal disease is rare. Accurate death rates from kidney disease are difficult to ascertain, in part because such illnesses are uncommon and in part, because they are dramatically underreported by at least 50% [personal communication 4/30/92, National Institute of Diabetic, Digestive and Kidney Diseases]. Dr. Thun indicated that impaired renal function is frequently underreported on death certificates even when the disease is sufficiently severe to require chronic hemodialysis (Modan referenced in Thun; Ex. 4-68). Under-reporting results because deaths from these diseases are coded as deaths due to complications arising from the treatment of these diseases or from sequelae to these diseases such as heart attack, stroke or diabetes.
Treatments for severe kidney diseases such as dialysis or a kidney transplant are available for those who can afford them. As Dr. Friberg indicated, several of his own patients had cadmium-induced uremia and died. If they had had the opportunity for dialysis or renal transplant, they could have been saved (Ex. 29). Such treatments, however, are grave, especially considering that early forms of kidney dysfunctions can be detected and more serious diseases can be prevented.
An additional part of the controversy over the significance of tubular proteinuria is the question of whether it is a reversible effect. Dr. Friberg testified that:
"The continuous release of cadmium from the liver, also after end of the exposure, means that the accumulation of cadmium will take place in the kidneys for a long time after end of exposure...there is much data showing that the proteinuria in chronic cadmium intoxication is irreversible.....studies ....show beyond doubt that several years after (medical) removal of the worker (due to proteinuria) there is either an increase of low molecular weight proteins in the urine or no change at all." (Tr. 6/6/90, pp. 74-75)
Drs. Bernard and Lauwerys conducted a follow-up study of workers who had been medically removed from occupational exposures due to cadmium nephrotoxicity (Ex. 35). Among male workers who had been removed from cadmium exposure because of elevated urinary excretion of B(2)-M, retinol binding protein (RBP), or albumin, the evidence was that kidney dysfunction increased significantly over the five year period. Once it has appeared, Drs. Bernard and Lauwerys concluded, cadmium-induced proteinuria is in most cases irreversible. Bernard and Lauwerys demonstrated that proteinuria slowly progresses. Despite their finding that this evolution was slow, the authors concluded that the onset of proteinuria should be considered to be an adverse health effect, since such cadmium nephropathy may progress to renal insufficiency.
Dr. Bond stated that the clinical significance of slight increases in urinary B(2)-M (for example, 350 ug/l) is uncertain, but that a repeated finding of B(2)-M levels twice that of normal would more likely reflect a permanent effect, based on his experience and the literature. (Tr. 7/18/90, p. 169) Dr. Bond also agreed that cadmium-induced proteinuria must be prevented or minimized in order to prevent material impairment of health. (Tr. 7/18/90, pp. 150-258, 175-176). About 20% of the cadmium workers that Dr. Bond has medically evaluated have elevated B(2)-M levels. Dr. Bond removed two of these workers from cadmium exposure in 1986 when their B(2)-M levels in the urine were 3000 to 5000 ug/l. Annual testing after removal indicated that urinary B(2)-M and cadmium levels did not decline appreciably. Dr. Bond stated that in his opinion, these two workers are not sick based on results from tests of their level of serum creatinine and alpha phosphatase which measure kidney function (Tr. 7/18/90, pp. 189-191). Dr. Bond did indicate, however, that he was "concerned" about the welfare of these two individuals because he did not know if they were likely to develop any further problems. (Tr. 7/18/90, p. 229) According to Jarup et al (Ex. 8-661) during the ten-year period of follow-up in his study, none of the cases of elevated B(2)-microglobulinuria (greater than 310 ug B(2)-M/g Cr) discovered in the high dose groups were reversible. The authors concluded that it was unlikely that any of these cases of tubular proteinuria would disappear after such a long follow-up time and that it was quite possible that more cases of tubular proteinuria would develop with a longer follow-up.
It is clear from the record of the rulemaking that despite some controversy, there is general agreement that renal tubular and glomerular lesions represent permanent loss of kidney functional reserve and that the lesions are irreversible. A worker with elevated levels of B(2)-M who does not experience overt symptoms of illness may succumb to other illnesses more rapidly. An infection or other condition which would not normally lead to serious illness but which compromises kidney function could overwhelm the remaining kidney capacity (Ex. 8-644). A worker who has only slightly elevated levels of B(2)-M may later develop proteinuria, even after cessation of exposures, or the worker may develop more severe forms of renal dysfunction. Such dysfunction is of great concern to OSHA. Loss of kidney function and renal compromise, described above, meet the definition of material impairment as intended in the OSH Act and as defined in this final standard (Sec. 6(b)(5)).
In summary, various world experts and others take 200 ug B(2)-M/g Cr either as the normal limit or as the lower limit of normal (Lauwerys, Ex. 8-447; Friberg, Ex. 29). The most widely used standard test for measuring concentrations of B(2)-M, Phadebas, established levels above 300 ug/L urine as being abnormal (Ex. L-140-1). All of these data and expert opinion lead OSHA to believe that the Agency could reasonably set the lowest B(2)-M trigger for enhancing medical surveillance from 200 ug to as high as 300 ug/g Cr. Both 200 and 300 ug/g Cr are considered to be very low levels.
On balance, OSHA has decided to set 300 ug/g Cr as the lowest B(2)-M trigger for the following reasons. OSHA believes that the medical surveillance requirements in this cadmium standard are, of necessity, very strict. As Dr. Friberg testified:
"OSHA's document...when implemented, will have a major impact to protect the workers' health. The proposed changes in PELs and the strict control measures required by OSHA may seem drastic. They are not drastic from the point of view of the protection of the worker, however. They seem drastic only because so little has been done in the past (Tr. 6/6/90; pg. 86-87)."
OSHA is aware that these requirements impose a substantial economic burden on employers. OSHA does not want to impose costs on employers for medical surveillance when it is uncertain whether the lower trigger level of 200 ug B(2)-M/g Cr will provide additional protection.
OSHA received comments on other medical surveillance protocols (Exs. 14-14-C; 77; 19-43-A; 107). The Agency believes that the essential elements for a sound medical surveillance protocol that were submitted by other hearing participants have been included in this program. However, OSHA chose to limit initial examinations as specified under (l)(2(ii) to three biological tests (CdU, CdB, B(2)-M) instead of routinely requiring the battery of tests some commenters requested (e.g., ASARCO, Ex. 107). OSHA also relies upon three biological monitoring results used in conjunction with each other, instead of only one parameter, as is the current practice in some industries (Ex. 14-6). The Agency has determined, based on record evidence, that one parameter, either CdU, CdB, or B(2)-M, is less reliable by itself to evaluate an employee's health status. Thus, OSHA requires three tests, initially and periodically thereafter.
As indicated above, the final medical surveillance program included in this standard is based upon the proposal (55 FR 4124), the memorandum further articulating that proposal (Ex. 46, July 2, 1990), and the other record evidence. In that memorandum, OSHA: (1) Indicated that the proposed medical surveillance section, paragraph (l), had elicited substantial comment and testimony at the hearings in June, 1990, in Washington, D.C.; (2) summarized the submissions; (3) presented medical surveillance provisions that had been modified in response to the comments and testimony; and (4) requested participants to submit further testimony and comments on these provisions and related issues. The main change to the provisions incorporated in the memorandum is that in this final standard employers are required to monitor an employee's CdB as well as CdU and B(2)-M. The change is based upon testimony and comments OSHA received on the proposal and memorandum (e.g. Exs. 19-2; 19-14; 19-33; 19-34; 19-40; 19-42; 19-43; 77; 82; 84; 101; 106; 107; 120; 123).
With the comments and relevant medical literature in mind, OSHA had to select particular biological levels to indicate greater and lesser risk of contracting cadmium induced disease and to trigger appropriate medical responses. Dr. Tyner, medical director of the Gates Nickel-Cadmium battery plant, stated, "The most important part of this proposed standard is the medical surveillance portion with the removal provisions...Medical surveillance must be mandated." (Ex. 19-2) Dr. Tyner stated that the proposed medical surveillance provisions are about right. "[Five] 5 ug/g Cr is a little low for removal... Tubular proteinuria is definitely a good reason to remove someone from cadmium exposure" (Ex. 19-2). His company removes workers at 300 ug/Liter Dr. Bond of SCM stated that an option to requiring each workplace to have a physician who knows about cadmium's toxicity is for OSHA to establish a medical surveillance protocol that would require proper medical examinations (Tr. 7/18/90, pp. 199-200, 244-248). Michael Coffman, manager of industrial hygiene for Federal-Mogul urges OSHA to "set objective, non-mandatory guidelines to assist physicians in determining under what circumstances medical removal is necessary" (Tr. 6/11/90; p. 126).
In response to such comments OSHA incorporated a significant degree of physician discretion into the final medical surveillance provisions, while specifying clear triggers for non-mandatory and mandatory medical actions, where needed.
OSHA believes that each of its choices of triggers for enhanced medical surveillance represents a cutpoint that is generally well established in the medical literature and is widely used in practice for assessing risk of cadmium induced disease and for initiating appropriate preventive or protective action. Of course, OSHA understands that one or more individual triggers might have been set somewhat above or below the particular level OSHA selected. However, the Agency is assured that the overall configuration of trigger levels makes sense as a program for protecting workers to the extent feasible from cadmium induced disease and also is internally consistent.
Take CdU as an example; if CdU biological monitoring results are within the so called "normal" range, at or below 3 ug/g Cr, the employer must provide currently exposed employees who are covered by medical surveillance with the minimum level of surveillance delineated in paragraphs (l)(2), (l)(3), and (l)(4). This minimum includes an initial medical exam (biological monitoring and work history), followed within 12 months by a periodic (biennial) full medical examination which includes biological monitoring, and then within the following 12 months by biological monitoring also on a biennial schedule. Thus, the minimum level of surveillance involves annual biological monitoring, either independent from, or as part of full medical examinations and biennial, full medical examinations.
However, if the employee's CdU are > 3 but < 15 ug/g Cr, the employer under paragraphs (l)(3)(ii) and (l)(4)(iv) of this standard must take a number of additional, limited steps to locate the source of the exposure problem, control the potential sources of overexposure in the workplace, and more closely monitor for potential changes in any of the employee's biological indicators. Furthermore, the employer is also required to provide the employee with a full medical examination within 90 days after receipt of the biological monitoring results.
To be more specific, for example, if the employee's biological monitoring results show CdU to be in excess of 3 ug/g Cr but at or below 15 ug/g Cr, then the employer is required to:
(c) Reassess the employee's work practices, personal hygiene, respirator use, if any, and smoking history and status;
(d) Reassess the respirator program, hygiene facilities, maintenance and effectiveness of relevant engineering controls; and
(e) Take reasonable steps to correct deficiencies found in the reassessments that may be responsible for the employee's excess exposure to cadmium.
In addition, due to the potential for disease associated with CdU levels above 3 ug/g Cr and especially above 5 ug/g Cr. (See Health Effects Section V). OSHA also is requiring the examining physician to consider and determine in a written medical opinion whether or not the employee, in light of all the medical evidence, should be medically removed from exposure to cadmium at or above the action level. If the physician determines that the employee need not be medically removed, the employer must:
(1) Continue to provide semi-annual biological monitoring of potential changes in the employee's biological indicators;
(3) Make periodic efforts to locate and control the workplace sources of the employee's problem until the CdU levels return to within the "normal" range.
Moreover, if the level of CdU exceeds 15 ug/g Cr, then under paragraphs (l)(3)(iii) and (l)(4)(iv) of this standard the employer must provide a full medical examination within 90 days after receipt of the results. The physician continues to be required to determine in a written medical opinion whether the employee should be medically removed from exposure to cadmium at or above the action level. If the physician determines that the employee need not be medically removed, the employer must continue to provide the same level of enhanced medical surveillance as is required at the next lower trigger level, except that biological monitoring must be conducted quarterly and periodic medical examinations must be provided semi-annually. The employer also must periodically continue his/her efforts to locate and control the workplace sources of the employee's problem.
More than that, if the biological monitoring results obtained during the medical examination confirm the initial (or periodic) monitoring results, that the employee's level of CdU exceeds 15 ug/g Cr, or CdB exceeds 15 ug/lwb, or B(2)-M exceeds 1500 ug/g Cr and in addition to the elevated B(2)-M level, CdU levels exceed 3 ug/g Cr or CdB levels exceed 5 ug/lwb, then the physician is required to medically remove the employee from exposure to cadmium at or above the action level.
With this provision for mandatory removal, OSHA is effectively eliminating the examining physician's discretion as to whether to remove the employee from cadmium exposure at or above the action level. OSHA believes that the risk of the employee having or developing kidney disfunction and perhaps other diseases is so high at these biological levels that the employee must be removed as soon as it is established by retesting that the earlier monitoring results are confirmed (Bernard and Lauwerys, Ex. 35; NIOSH, Ex. 128; Lauwerys, Ex. 8-718; Roels, Ex. 57-K; Buchet, Ex. 8-201)).
However, to avoid the possibility that a cadmium exposed worker's confirmed, very high B(2)-M levels might be attributable to something other than cadmium exposure, OSHA is requiring that, for mandatory medical removal based on high B(2)-M levels, the B(2)-M levels must be supplemented by abnormal levels in one of the two cadmium-specific biological parameters, CdB or CdU, as well. Thus, OSHA seeks to assure that removal for elevated levels of B(2)-M be carefully restricted to employees with high risks of adverse material impairment of health associated with exposure to cadmium.
Medical evidence in general would support mandatory removal at lower levels than established in paragraph (l)(3)(iii) (Exs. 8-644; L-140-51; 35). However, OSHA is mindful of other important considerations that tend to weigh against currently requiring medical removal at lower biological levels. First, medical removal is a dramatic intervention that may have potentially dire, unintended life consequences for the employee and could be very costly to the employer as well. Even as medical removal provides one reasonable way to deal with an employee's medical problem, it may contribute to, or create other problems. For example, if a veteran worker is removed because of high biological monitoring results and his/her subsequent results do not fall to or below the "normal" level, which would allow return of the employee to his/her former job status, the employee thereafter might be terminated and become, practically speaking, unemployable in today's cadmium exposed jobs. Second, individuals' vulnerabilities and susceptibilities to cadmium toxicity vary somewhat, especially at lower levels of exposure such as those under the new TWA PEL of 5 ug/m(3). The numerical mandatory removal limits have been selected using Agency judgement as to the need to protect the sensitive portion of the worker population without removing too many workers who will not develop kidney impairment. And third, veteran cadmium-exposed workers, who were occupationally exposed to much higher levels of cadmium in the past, still are employed in the workplace. For veteran workers near retirement, a complex decision that is at once medical, social and economic has to be made concerning medical removal. This decision is best made by the examining physician and the individual worker in consultation. Fourth, with large numbers of veteran workers still in the workforce, mandatory removal at relatively low levels may create feasibility problems for many employers.
Considering the pros and cons for setting lower mandatory removal triggers, OSHA recognized compelling arguments on both sides. In light of this reality, OSHA tried to take reasonable account of legitimate, conflicting concerns by steering a middle course. To protect worker health, the Agency set lower removal triggers at the discretion of the physician. OSHA believes that while the final standard allows for discretionary medical removal at low levels (e.g., using CdU as an example, as low as just above 3 ug Cd/g Cr), physicians generally will not remove workers at these levels. OSHA does not expect physicians to remove workers when they first exceed "normal" levels or at low levels. Before 1999, workers need not be medically removed at or near these levels, unless in the physician's opinion and after full review of all the pertinent medical information the physician deems it necessary to do so in the interests of the health of a particular worker.
Nonetheless, by providing the option of discretionary removal at these low levels, OSHA believes that the physician and the employee will become aware that increased risk of kidney dysfunction exists at these levels, and they will consider other actions short of medical removal to minimize or avoid permanent damage, e.g., diet, use of certain broad-spectrum antibiotics and other prescription medications, use of other non-prescription medications. The physician and the employee should be aware of the risks in order to mitigate the influence of other factors that might rapidly overwhelm the worker's remaining functional capacity in cases where some dysfunction has already occurred even though the worker's test results are below the mandatory removal levels.
In further recognition of the countervailing factors listed above, the Agency phases in lower levels for mandatory requirements over nearly six years. Thus, in paragraphs (l)(3)(iv) (and (l)(4)(iv)) mandatory medical removal is required after January 1, 1999 whenever biological testing during a physical exam confirms earlier results that CdU is >7 ug/g creatine, CdB is > 10 ug/lwb, or B(2)-M > 750 ug/g Cr and in addition to elevated B(2)-M levels CdU levels exceed 3 ug/g Cr or CdB levels exceed 5 ug/lwb. Support for the particular levels chosen for removal can be found in the health effects section earlier in this preamble and in the record of the rulemaking. For example, Dr. Bond, who testified on behalf of SCM, stated that the clinical significance of slight increases in B(2)-M (for example, 350 ug/L) is uncertain, but that a repeated finding of B(2)-M levels twice that of normal would more likely reflect a permanent effect, based on his experience and the literature (Tr. 7/18/90, p. 169). Dr. Bond also agreed that cadmium-induced proteinuria must be prevented or minimized in order to prevent material impairment of health. (Tr. 7/18/90, pp. 150-158, 175-176).
By phasing in mandatory removal requirements at lower levels, OSHA expects that most of the problems associated with immediately imposing such lower levels will be avoided. For example, employers' efforts over the intervening years to comply with this standard, especially in the face of prospects of still lower mandatory removal triggers, are likely to control cadmium exposures in the workplace to the extent feasible. Moreover, the normal infusion of new workers not previously occupationally exposed to cadmium in conjunction with normal levels of turnover and the retirement of veteran workers will produce a workforce most of whose members have considerably lower body burdens of cadmium. Taken together, these developments should make mandatory removal at lower levels generally feasible for employers and less potentially burdensome for employees.
OSHA's tiered structure for progressively enhanced medical surveillance incorporates a parallel structure for progressively reduced surveillance, which is triggered at each tier by sufficiently lowered biological test results. At each level of enhanced medical surveillance there is a mechanism for reducing medical surveillance when levels of all three biological parameters fall below specified trigger levels. Thus, for example, the enhanced medical surveillance triggered by paragraph (l)(3)(ii), where levels of CdU > 3 ug/g Cr, B(2)-M > 300 ug/g Cr, CdB > 5 ug/lwb, is no longer required once the employee's levels of CdU fall to or below these levels. Thereafter, as long as the employee's biological monitoring results all remain within the "normal" range, the employer is required to provide only the minimum level of medical surveillance.
These medical surveillance provisions were developed with a primary focus on currently exposed employees. However, under paragraphs (l)(1)(i)(B), (l)(2)(i), (l)(3)(i)(B), (l)(3)((ii)-(vi), (l)(4)(v), and (l)(8), they apply as well to employees who may no longer be exposed to cadmium. Thus, the employer must provide medical surveillance to any employee who was exposed to cadmium prior to the effective date of this standard, unless the employer can demonstrate that the employee did not work for the employer in jobs with cadmium exposure for an aggregated total of more than 60 months in the years prior to the effective date of this standard.
OSHA understands that it may be difficult at times for the employer to demonstrate that the employee did not work for the employer in cadmium exposed jobs prior to the effective date of this standard for a total of 60 months or less. Consequently, the Agency does not require the employer to provide a certain proof to satisfy the employer's burden of proof. Rather, OSHA expects the employer to provide sufficient evidence to make it unlikely that the employee was exposed for a total of 60 months. The evidence must be reasonably persuasive in light of the protective purposes of medical surveillance. The evidence may be probablistic or circumstantial where direct evidence is neither available nor easy to develop.
Thus, on the one hand, for the reasons presented above, OSHA has placed the burden of proof on the employer to show that a currently or previously cadmium-exposed employee need not be provided medical surveillance under the criteria supplied in paragraph (l)(1) of this standard. And OSHA intends that these criteria should be interpreted in a manner that best assures medical protection to employees who appear potentially in need of it. On the other hand, OSHA does not intend to impose an unsustainable burden on the employer. On the contrary, the kind of proof that a reasonably conscientious employer could present generally should be viewed as satisfying the employer's burden of proof.
For employees to whom the employer must provide medical surveillance because of exposure to cadmium prior to the effective date of this standard, the main aim of initial medical surveillance, as previously indicated, is to identify as quickly as possible those with abnormally high biological test results. Once identified, these employees are then tracked through paragraphs (l)(3)(ii)-(iv) and (l)(4)(iv) into the same level of enhanced medical surveillance as currently exposed workers with similar test results. By contrast, for past exposed employees whose initial biological monitoring results are all within the normal ranges, the aim is to phase out periodic medical surveillance as expeditiously as prudence will allow. Consequently, under paragraph (l)(3)(i)(B) the employer is required to retest the employee within one year (12 months) of the initial exam. If the results of that retest confirm that all the levels remain normal, then under paragraph (l)(4)(v) the employer need not provide further medical surveillance to the employee.
The tiered structure of triggers for progressively enhanced and progressively reduced medical surveillance, outlined with regard to CdU, is utilized in paragraphs (l)(3) and (4) of this standard for CdB and B(2)-M levels, as well. Paragraph (l)(3) provides the required, tiered actions the employer must take in response to the initial biological monitoring results. Paragraph (l)(4) provides the requirements for periodic medical surveillance, which generally replicate the tiered requirements for biological monitoring in paragraph (l)(3). These parameters are required to be monitored on the same schedule as CdU.
In order to assist the employer, employee and the physician in understanding and implementing the medical surveillance provisions in this standard, OSHA has provided a Summary Chart of the provisions in the regulatory text and an example of a form for employee-notification-of-results in Appendix A.
In addition to biological monitoring, periodic medical examinations also are required. Paragraph (l)(4)(ii) sets out the required contents of those examinations. The examination must include a detailed medical and work history and a conventional physical examination, with specific emphases on potential cadmium induced diseases and their biological indicators. Thus, particular attention is given to the respiratory and urinary systems, the same biological monitoring that is part of the initial examination, and additional blood and urine analyses.
Based upon numerous comments in the record indicating that OSHA should focus the content of the medical exam on potential lung and kidney disease as the critical effects, the Agency in this final standard has eliminated certain requirements from the proposed standard and added others (NIOSH, Ex. 19-26; Bond, Ex. 77; ASARCO, Ex. 107). For example, OSHA eliminated the proposed requirements for liver enzyme testing. While cadmium is regarded as a late-stage toxin to the liver, at least one commenter stated that there are no reports of cadmium-induced hepatocellular damage, therefore, medical tests for liver function are unjustified (Exs. 8-86, Ken Storm; 19-14, Monsanto). Dr. Friberg stated that there was no reason to include liver enzyme tests unless they are normally performed (Ex. 29).
A complete blood count is required as part of the full medical examination under paragraph (l)(4)(ii)(F). This test is expected to identify cases of anemia. According to Dr. Stopford, a physician with the Duke University Medical Center, a platelet count, which is already part of most commercially-available complete blood count panels, would help detect the toxic effects of cadmium on the spleen and liver, with associated anemia (Exs. 14-14B, 14-14-D). Dr. Stopford submitted comments to the record which included a case report on a worker with severe liver dysfunction (Ex. 14-14). Dr. Stopford considered this case history to be cadmium related.
The proposed microscopic examination of urinary sediment was eliminated in the final standard, because comments were submitted that this test would provide little useful information (Ex. 29). Evaluation of the musculoskeletal system was eliminated from the physical exam but not from the medical history because commenters stated that musculoskeletal damage is seen only as a result of cadmium-induced kidney failure and probably will not be seen in the U.S. occupational environment (Exs. 19-14, 29; Tr. 6/6/90 pp. 112).
On the other hand, OSHA added other requirements to the final standard, for measuring urinary pH and creatinine in urine, as specified under paragraph (l)(2)(ii)(B)(2), because the Agency learned that they are needed to standardize and control the accuracy of measurements of cadmium and B(2)-M (Friberg, Ex. 8-86, Vol. I, pp. 83; Phadebas, Exs. L-140-1, 4-47, L-140-45). Several commenters supported the requirement to measure creatinine in urine to control for diuresis if they do not do so at present (Exs. 84, 19-40).
Specifically, OSHA requires the following elements in the periodic medical examination for the following reasons. First, under paragraph (l)(4)(ii)(A) the Agency requires a detailed medical and work history to provide the physician with information, including employee reported symptoms, to be used in conjunction with a complete physical examination and biological monitoring. This information can assist the physician in determining the employee's health status, possible past exposures to cadmium or other toxic substances that may have damaged organs or systems susceptible to cadmium toxicity, and suitability for work in a job where cadmium exposure may occur. Questions 3-11 and 25-32 in Appendix D are a required part of the medical history because they relate to the increased risk of kidney disease, lung cancer, bronchitis, fibrotic lung changes, and emphysema-like changes in the lung that can occur as a result of cadmium exposure (Ex. 19-26). The information about the respiratory system is also important for evaluating an employee's fitness for respirator use.
Second, a complete physical examination is required to enable the physician to directly and more broadly assess the health status of the employee and to pursue any other indications of potential medical problems that may be relevant to cadmium exposure. In the physical examination, the physician can assess other potentially serious adverse effects associated with cadmium exposure, like dermatoses, eye irritation and elevated blood pressure, which are beyond OSHA's primary focus on kidney and lung disease. A complete physical examination is particularly useful to the physician when exercising his or her discretion to determine whether the employee must be medically removed from exposure to cadmium under paragraphs (l)(3)(ii)-(iv).
Third, under paragraph (l)(4)(ii)(C) a chest X-ray is required at the first periodic medical examination, at the termination of employment examination (paragraph (l)(8)), and periodically as determined by the examining physician. An initial chest X-ray, although not useful for preventing lung cancer, can be useful for diagnosing lung cancer and other non-malignant lung diseases which are caused by cadmium exposure (e.g., Kazantzis Tr. 6/8/90, pp. 156-157), such as bronchitis, fibrosis and emphysema-like changes in the lung. It also provides baseline data upon which to assess any subsequent lung function changes (Ex. 19-26-F). OSHA is leaving the determination of frequency of chest X-rays to the discretion of the physician and is not requiring periodic chest X-rays because of the potential risk of adverse effects to the employee from too frequent X-rays (Ex. 19-14).
Fourth, pulmonary function tests are required to provide specific information about the employee's lung capacity and respiratory flow rate. This information is useful to diagnose bronchitis and emphysema, to provide baseline data on lung function, to evaluate any loss of lung function, and to provide baseline information of lung function status upon which to assess any subsequent lung function changes. This information may also be useful in assessing the health of employees who wear respirators. It is recommended that pulmonary function testing be conducted in accordance with the American Thoracic Society's criteria (Ex. 8-663).
Fifth, since a central purpose of the medical examination is to provide further information on the critical organs and critical effects associated with cadmium exposure, OSHA has included in the examination additional analyses of blood and urine and, for males over 40 years of age, prostate palpation or other at-least-as-effective diagnostic test(s). Specifically, OSHA has included a determination of the blood urea nitrogen (BUN) and serum creatinine levels and a complete blood count. Elevations in BUN and serum creatinine levels are indicative of kidney disease. For example, BUN and serum creatinine levels increase with the loss of glomerular filtration. Although BUN and serum creatinine tests are not cadmium specific, they do provide additional information about kidney function and kidney disease that is important for physicians to know in determining an employee's suitability for work in a cadmium-exposed job (Ex. 107). Regardless of whether the kidney disease is caused primarily by cadmium from occupational sources, and indeed regardless of whether the kidney disease is cadmium induced at all, the very existence of kidney disease in a cadmium exposed worker is serious cause for concern. OSHA in the final standard also has required a complete blood count, which most industry representatives stated was a very useful test for cadmium exposed workers (Dr. Bond, Ex. 77; Dr. Hine, ASARCO, Ex. 107; but see Ex. 19-14).
With regard to additional urine analysis, OSHA is also requiring a determination of the albumin, glucose and total and low molecular weight protein levels. While albumin and glucose tests are not cadmium specific, they can provide additional information about kidney function and kidney disease, which also is important for physicians to know in determining an employee's suitability for work in a cadmium-exposed job (Ex. 8-669-A). Elevated levels of albumin and glucose in urine may be indicative of a loss of glomerular function. In addition, the increased urinary excretion of low molecular weight proteins and total proteins (i.e., low and high molecular weight proteins combined) is associated with early renal damage.
Prostate palpation or other equally effective diagnostic tests are required to diagnose prostate cancer. Cancer of the prostate has been observed among cadmium exposed workers and was the first indication that cadmium exposure is associated with cancer. Although recent studies do not confirm the association between cadmium exposure and death from prostatic cancer, OSHA believes it would be premature and imprudent at this time to act as if exposure to cadmium did not increase the risk of prostatic cancer. Indeed, many scientists and physicians attribute the reduction in cadmium induced prostate cancer death rates not to a lack of association between cadmium exposure and prostatic cancer but to two other factors: the improved early diagnosis and treatment of prostate cancer, which has reduced the death rates from this disease, and the reduced levels of cadmium exposure (Ex. 19-42b; Environ Report, Ex. 12-39, ATSDR, Ex. 8-689). OSHA therefore, as prudent public health policy, requires inclusion of prostate palpation or other equally effective diagnostic tests for prostate cancer in men over 40, the primary target group for prostatic cancer.
Finally, OSHA has authorized the physician to require any additional tests deemed medically necessary. OSHA believes that it is important that the examining physician have such discretion because, notwithstanding statistical probabilities, individual susceptibilities to, and tolerance levels and thresholds for, cadmium toxicity differ. The physician is in the best position to specifically determine which additional tests, if any, would be useful in evaluating the health status of the individual employee.
Paragraph (l)(5) provides for additional actions triggered by any unspecified but generally accepted abnormal findings consistent with cadmium toxicity that are identified through medical examinations. For example, in his guide for physicians who medically evaluate workers exposed to cadmium, Dr. Lauwerys indicates that levels of total protein in urine above 250-350 mg/g Cr may require additional medical attention and referral to a nephrologist (Ex. 8-447).
In devising paragraph this medical surveillance program, OSHA sought to provide objective markers for action while recognizing that single monitoring results generally should not be used in isolation from other results or other biological parameters or a holistic evaluation of the worker`s health to determine a worker's fitness for cadmium exposed work. OSHA tried to provide a significant role for physician discretion in this evaluation, without leaving the physician devoid of boundaries on his/her discretion and guidelines to action.
Paragraph (l)(6)(i) requires the employer to provide a limited medical examination prior to the employee using a respirator to determine the employee's fitness for wearing a respirator. This is a change from the proposal, where a full medical examination, including elements designed to test the employee's fitness to wear a respirator, was required within 30 days after the employee was assigned to a job requiring the use of a respirator. Based on record evidence (Exs. 57, 19-22, 106), OSHA believes that a full medical examination is not necessary to determine the employee's fitness to wear a respirator and therefore in this final standard has only retained those elements of the full medical examination that are useful to such a determination. Based on comments to the record (e.g., ASARCO, Ex. 107), OSHA also believes that the examination to determine an employee's fitness to wear a respirator should be performed prior to the employee using a respirator. The examination must include a detailed medical and work history, with emphasis on questions 3-11 and 25-32 in Appendix D, a blood pressure test, and any other tests or procedures, such as pulmonary function tests or a physical examination, that the examining physician deems appropriate. OSHA is requiring a detailed medical and work history with specific questions about past respiratory and cardiovascular problems, smoking history, and other medical problems that might either interfere with, or be exacerbated by the employee wearing a respirator, because this information should be gathered and medically assessed prior to the employee using a respirator.
In addition, the examining physician under (l)(6)(ii) should review the results of any biological monitoring of the employee's CdU, CdB and B(2)-M. OSHA believes that the examining physician should assess these biological data indicating whether the employee has been overexposed to cadmium, has an abnormally high body burden of cadmium, or has kidney disease before the physician certifies the employee as fit to wear a respirator in a job in which the airborne cadmium levels are above the PEL.
Where the employee has actually exhibited difficulty in breathing during a respirator fit test or while using a respirator, then, under paragraph (l)(6)(iii), the employer is required to provide a full medical examination in accordance with paragraph (l)(4)(ii). The examination is required to determine the employee's fitness to continue wearing a respirator and his or her health status relative to further exposure to cadmium.
If the results of the medical examination under paragraph (l)(6)(i) or (iii) are abnormal, medical limitation of respirator use, including prohibition of such use or requiring that the employee be provided with a more appropriate respirator (e.g., a PAPR), shall be considered. If the employee is allowed to continue to wear a respirator the physician is required to periodically evaluate the employee's continuing fitness to wear a respirator as often as medically necessary. If the employee is found unable to wear a respirator, he or she shall be medically removed under paragraph (l)(11) of this standard from any current job where the employee is exposed to cadmium above the PEL.
In addition to the medical surveillance required in paragraphs (l)(2)-(6), paragraphs (l)(7) and (8) provide for further medical examinations in the event of acute exposure to cadmium because of an emergency or upon termination of employment, respectively. Emergency examinations are required because it would be imprudent to delay evaluating the effect of acute exposure to cadmium on the employee until the next periodic medical examination. Indeed, in an emergency, immediate medical attention may be necessary.
The employer, with one exception, is required under paragraph (l)(8) to provide a medical examination at the termination of employment to all workers to whom the employer at any time was required under paragraphs (l)(1)(i) or (l)(7) to provide medical surveillance. Thus, for example, all workers who in any 12 month period after the effective date of this standard were exposed to cadmium at or above the action level on 30 or more days by the employer and all workers who had emergency medical examinations would be entitled to the examination required by paragraph (l)(8). In addition all workers exposed prior to the effective date of this standard who were covered by medical surveillance also would be entitled to a medical examination at termination of their employment, unless under paragraph (l)(8)(ii) the employer discontinued periodic medical surveillance as authorized under paragraph (l)(4)(v).
This requirement is somewhat different from the proposal. Under the proposal the employer would have had to provide a termination of employment examination to all employees who at any time had been eligible for a full medical exam under proposed paragraph (l)(3). However, under the proposal employers were not obligated to provide a full medical exam, or indeed any medical surveillance at all, to employees who had been exposed by them to cadmium exclusively prior to the effective date of this standard. The effect of the proposal, then, would have been to require employers to provide examinations at termination of employment only to employees who were exposed by them to cadmium at or above the action level after the effective date of this standard.
Unlike the proposal, the final standard does cover employees who may have been excessively exposed to cadmium prior to the effective date of this standard. However, the employer would not have to provide these employees with a termination of employment examination if their biological monitoring results had previously returned to "normal" levels and periodic medical surveillance of them had been discontinued in accordance with paragraph (l)(4)(v).
The requirement for a medical examination at the termination of employment is in keeping with other OSHA standards (e.g., Asbestos, Coke Oven Emissions, Arsenic, Acrylonitrile, and Ethylene Oxide). The need for this requirement in the cadmium standard is due, in part, to the way cadmium is transported, distributed, and stored in the body. After absorption, cadmium is transported via the blood stream to other body parts, where it is bound to proteins and stored. Low excretion rates lead to a very efficient retention of cadmium in the body. The biological half-life of cadmium in various compartments of the body ranges from 20-37 years or more (Ex. 8-86-B). It is not surprising, then, that even after cessation of exposure to cadmium in the workplace, growing evidence indicates that cadmium stored in one body compartment can be transported to the kidney. In this way, cadmium proteinuria may develop years after exposure in the workplace has ceased. There is, therefore, little tendency for proteinuria (e.g., B(2)-M > 1000 ug/g Cr; Ex. 30), to decrease after removal from external cadmium exposure if past cadmium exposures were high (Ex. 35). Instead there can be an increase, which is substantial for some workers, and kidney damage can progress to a more severe stage of disease (Ex. 8-668). Consequently, it is important that the employee's health status regarding cadmium accumulation in the body be once again assessed at the employee's termination of employment.
Failure to find evidence of cadmium toxicity in the examination at termination of employment should not be viewed as a "clean bill of health." Physicians should use the opportunity of the examination to once again advise the employee of his/her cadmium body burden and prognosis, and to make recommendations for medical management and follow up. For the worker, this information allows him/her to determine the courses of action necessary to sustain health.
As part of the medical surveillance program established in this standard, the employer is required by paragraph (l)(9) to provide the examining physician with the following information: a copy of the standard and its appendices; a description of the affected employee's former, current, and anticipated duties as they relate to the employee's occupational exposure to cadmium; the employee's former, current, and anticipated future levels of occupational exposure to cadmium; a description of any personal protective equipment and respirators used, or to be used by the employee, including when and for how long the employee has used that equipment; and results from previous biological monitoring and medical examinations that were provided by the employer to the employee. Making this information available to the physician will aid in the evaluation of the employee's health and fitness for particular cadmium-exposed job assignments. This provision is essentially the same as in the proposal (55 FR 4126).
Under paragraph (l)(10), the employer is required to obtain a written opinion from the examining physician promptly after a medical examination of an employee. The written medical opinion must contain the results of the medical examination as they relate to occupational exposure to cadmium, any detected medical conditions relevant to further cadmium-exposure, any recommended restrictions upon the employee's exposure to cadmium or upon the use of protective clothing or equipment, and other elements of (l)(10)(i)(A-E). This written opinion by the physician, which is given to the employer, must include a statement indicating that the physician has provided the results of the tests, the medical examination, any diagnoses, and an evaluation of the employee's prognosis to the subject employee in a manner that appropriately informs the employee of the results of the tests. A suggested format for such a statement is included Appendix A. The physician is not to reveal to the employer orally or in his/her written medical opinion specific findings or diagnoses unrelated to occupational exposure to cadmium. Under paragraph (l)(15)(i), the employer must give a copy of the written medical opinion to the affected employee within two weeks after receipt thereof.
The purpose of requiring the examining physician to supply the employer with a written opinion is to advise the employer of the medical basis for determining placement of employees in cadmium-exposed jobs. The requirement that a physician's opinion be in written form will assure that employers have had the benefit of this information which can be referred to as needed. The requirement that the written medical opinion from the examining physician include the physician's diagnosis and prognosis for the employee and other elements stated in paragraph (l)(10)(i)(A-E) is to assure that the employer and the employee are apprised of all medical information that is meaningful and relevant to the employee's initial or continued exposure to cadmium in the workplace. The requirements that the written medical opinion be promptly provided after the examination to the employer and that the employer, in turn, provide a copy of the physician's written opinion to the employee within two weeks of its receipt (paragraph (l)(15)(i) is to assure that notice of potential adverse health effects is promptly communicated to the employer and employee so as to minimize potential risk to the employee's health.
A requirement has been included in paragraph (l)(10)(i)(E) that the employer obtain a statement from the examining physician that the employee has been informed of the results and medical implications of the medical examination. It is the employer's responsibility to assure that the employee has been so informed. A suggested format for such a statement is provided in Appendix A. In conjunction with the requirement that the employee must be provided with a copy of the physician's written opinion, OSHA is assured that the employee will be informed of the results of the medical examination. The requirement that the physician sign the opinion is to assure that the information that is given to the employer has been seen and read by the physician and that the physician has personally determined whether the employee may continue to work in cadmium-exposed jobs.
The purpose in requiring that specific findings or diagnoses unrelated to occupational exposure to cadmium not be included in any oral or written opinion provided by the physician to the employer under paragraph (l)(10)(iii) is to encourage employees to take the medical examination by removing any concern that the employer will obtain adverse information about their health status that has no relation to occupational exposures. This provision has been included in prior standards (e.g., final arsenic standard, 43 FR 19621).
Medical Removal Protection (MRP):
Paragraphs (l)(11) and (l)(12) provide for medical removal protection and medical removal protection benefits, respectively. These paragraphs apply only to workers who are exposed to cadmium at or above the action level. Paragraph (l)(11) generally requires the employer to remove workers from exposure to cadmium on each occasion that the risk of material impairment to the employee's health or functional capacity from continued exposure to cadmium is considered too high. More specifically, the employer must remove the employee from excess exposure to cadmium in three cases . First, the employee must be removed from exposure at or above the action level on each occasion that a physician determines in a written medical opinion that medical removal is required under paragraphs (l)(3) and (l)(4). In accordance with these paragraphs, this determination may be based upon elevated levels of the employee's CdU, CdB or B(2)-M. Alternatively, the determination may be based on evidence of illness, other signs of cadmium-related dysfunction or disease, or any other reason deemed medically sufficient by the physician. Second, the employee must be removed from exposure at or above the action level where medical removal is mandatory under paragraphs (l)(3)(iii) and(iv)(C) and(l)(4)(iv)) if the employee's levels of CdU, or B(2)-M or CdB are confirmed to be in excess of the trigger levels specified in those paragraphs. Third, the employer must remove an employee from cadmium exposure above the PEL whenever a physician determines in a written medical opinion that the employee cannot wear a respirator. The MRP provisions apply only to such an employee when he/she already is functioning in a job where a respirator is required and it is then determined that the employee is unable to wear a respirator and therefore must be removed. MRP does not apply to a new employee who is determined in a pre-assignment medical examination for respirator use to be unable to wear a respirator. Nor does it apply to a worker found to be medically unable to wear a respirator that is required in a job to which the worker seeks to transfer or to a worker who has volunteered to wear a respirator.
Each time the employee is medically removed under paragraph (l)(11), paragraph (l)(12) requires the employer to provide medical removal protection benefits for up to a maximum of 18 months, thereby maintaining the employee's total earnings and other employment rights for that period as if the employee were not removed.
Medical removal protection (MRP), in paragraph (l)(11) of the cadmium standard, is a protective, preventive health mechanism that is integrated with the medical surveillance provisions of this standard. MRP requires employers to temporarily remove from jobs with significant exposure to cadmium those employees who are discovered through medical surveillance to be at the highest risk of sustaining material impairment to health from continued exposure to cadmium. The medical removal protection benefits (MRPB) provisions in paragraph (l)(12) of the standard require employers, on each occasion that an employee is medically removed under paragraph (l)(11), to provide temporary economic protection to the removed employee.
MRP and MRPB have previously been included in OSHA's Lead and Benzene standards, 29 CFR 1910.1025 and 1910.1028, respectively. The MRP and MRPB provisions of this standard are modeled upon similar provisions incorporated in the lead standard. The lengthy discussion and justification for MRP and MRPB provided in Attachment C to that standard (43 FR 54440-73, Nov. 21, 1978) are, to the extent relevant, hereby adopted in this preamble to the cadmium standard.
MRP, contributes directly to achieving one of the aims of the OSH Act, assuring to the extent feasible "that no employee will suffer material impairment of health or functional capacity even if such employee has regular exposure to the hazard dealt with by the standard for the period of his working life" (Sec. 6(b)(5)). The term "material impairment" is not defined in the cadmium standard since it encompasses multifarious conditions. However for purposes of this standard, "material impairment" is intended to be interpreted as broadly as is necessary to achieve the preventive purposes of the Act. "Material impairment," thus, is intended to include early stage diseases and medical dysfunctions and is not intended to necessarily imply the existence of overt illness, irreversible damage, or clinical symptoms. In practice, the term will be defined in a manner consistent with sound medical practice through the physician determination mechanisms in the cadmium standard.
MRP and MRPB, separately and in combination, serve three main interrelated purposes. First, together, they increase employee participation and confidence in the standard's medical surveillance program. Second, by requiring the employer to remove employees with the highest risk of suffering cadmium induced disease from significant exposure to cadmium and to provide removed employees with enhanced medical surveillance, MRP serves both to prevent the onset of disease and to detect and minimize the extent of existing disease. Third, MRPB allocates the costs of medical removal protection to employers. The medical surveillance program in the cadmium standard represents a major element in OSHA's integrated approach to preventive health under the OSH Act. The success of the preventive approach crucially depends on voluntary and meaningful worker participation in medical surveillance.
Medical surveillance can only be effective in preventing (and minimizing) disease where workers: (1) Voluntarily seek medical attention when they feel ill; (2) refrain from efforts to conceal their true health status; and (3) fully cooperate with examining physicians to facilitate accurate medical diagnoses and effective treatment. This sort of employee participation and cooperation cannot be evoked by coercion. It will occur only where no major disincentives to meaningful worker participation exist. Without such participation, it would be much more difficult, if not impossible, to adequately monitor workers' health and to identify workers who need temporary medical removal. And without effective medical surveillance, the overall protection afforded by the cadmium standard would be substantially diminished.
MRP is a logical and natural culmination of medical surveillance. In order to protect the health of workers identified by the medical surveillance program as most in need of protection, MRP mandates temporary removal from significant cadmium exposure and enhanced medical surveillance. Without MRP, employers would be free to maintain high-risk workers in their current, high-exposure jobs, which would not be sufficiently protective of their health. Alternatively, employers could choose to terminate, temporarily lay off, or transfer those workers from higher-paying, cadmium-exposed jobs to lower-paying, less-exposed jobs. This might be protective enough but it could seriously damage workers' livelihood.
they could decline to participate in medical surveillance at substantial risk to their health, or they could agree to participate in medical surveillance at substantial risk to their livelihood. In either case, the effectiveness and integrity of the medical surveillance program would be compromised. In such circumstances, countless workers doubtless would be very hesitant to participate in medical surveillance. Consequently, in part to safeguard the medical surveillance program, both MRP and MRPB have been included in the standard.
With MRP, workers are assured of being removed to low exposure jobs when necessary to protect their health. And with MRPB, workers are assured that, if they fully participate in medical surveillance and if the results of medical surveillance require removal from their high-cadmium-exposure jobs, their wages and job status will be protected for an extended period. During that period, the examining physician can determine whether the removed workers' health has sufficiently improved so they may be returned to their previous jobs, or they must be permanently removed from further exposure.
Viewed as a means to achieve the health goals of the standard, temporary medical removal is a method of control, not so different in this respect from engineering controls, which control airborne cadmium emissions. Implementing MRP, like other controls, necessarily entails certain costs. The employer, for example, might incur certain costs due to the temporary loss of a trained and experienced employee. Without MRPB, a removed worker might lose substantial earnings or other rights or benefits by virtue of the removal. These costs are a direct result of reliance on MRP to protect worker health.
OSHA considers the costs of protecting worker health to be an appropriate cost of doing business since employers are obligated by the OSH Act to provide safe and healthful places of employment. Consequently, the costs of MRP, like the costs of providing respirators and engineering controls, are placed on employers rather than on the shoulders of individual workers unfortunate enough to be at risk of sustaining material impairment to health due to occupational exposure to cadmium. Nevertheless, MRP should not be understood as an alternative to primary control of workers' exposure to cadmium. Rather, MRP is intended by OSHA to be used exclusively as fall-back protection, where other, primary methods of controls have proven to be insufficiently protective.
Precisely because MRP will impose additional costs on employers, MRP can increase the protection afforded workers by the cadmium standard not only directly by improving medical surveillance but also indirectly by providing employers with economic incentives to comply with other provisions of the standard. The costs of MRP are likely to decrease as employer compliance with other provisions of the standard increases. Employers who comply with other provisions of the standard should have to remove relatively few employees. With only a small number of employees requiring removal, complying employers are more likely to be able to find positions available to which removed employees can be transferred. By contrast, employers who make only cursory attempts to comply with the central provisions of the cadmium standard are likely to find that the greater their degree of noncompliance, the greater the number of employees requiring medical removal and the greater the associated MRP costs. Thus, MRP serves as a strong stimulus for employers to protect worker health and rewards employers who through innovation and creativity derive new ways of protecting worker health not contemplated by the cadmium standard.
One limiting factor on the potential of MRP to prevent disease is that, once an employee has developed proteinuria (e.g., B(2)-microglobulinuria), in many cases medical removal can only slow and minimize the progression of the disease or dysfunction but cannot necessarily prevent the development of more serious disease. Medical removal, by severely restricting the intake of cadmium on the job while providing time for natural excretion to eliminate from the body previously absorbed cadmium that has accumulated in various body compartments, will effect a net decrease in the body's cadmium burden. However, the very process that reduces the overall body burden of cadmium leads to an increase in the kidney burden of cadmium (though generally to a smaller increase than if the employee had not been removed at all from significant exposure to cadmium). This is because the decrease in overall body burden of cadmium is achieved through the excretion of CdU, which passes through the kidney, thereby increasing the amount of cadmium in the kidney, where it continues to cause damage.
Thus, temporary medical removal can protect a removed employee from additional cadmium exposure but may not in some cases be a mechanism for restoring normal kidney function where cadmium-related proteinuria, or more severe cadmium-related kidney disease is already present. For workers who have already developed cadmium induced kidney disease, the primary purpose of temporary medical removal is to provide intense medical surveillance while minimizing both further exposure to cadmium and further progression of the dysfunction/disease during the period in which diagnosis and prognosis of the individual's particular cadmium-related dysfunction/disease can be fully evaluated. Consequently, early detection of excess exposure to cadmium through medical surveillance and early action to prevent excess exposure is critical. The medical surveillance program and the MRP provisions in the cadmium standard were devised with early detection and early action in mind.
Cadmium is naturally excreted very slowly from the body. It is excreted slowly because rapid elimination of cadmium would risk overburdening and damaging the kidney. This fact has two implications. First, because of the risk of kidney damage arising from the rapid elimination of cadmium from the body, current methods of chelation are unsafe for reducing cadmium in the body. Second, since there is no safe way to accelerate the excretion of cadmium, natural elimination is the only means that can be relied upon to reduce body burden and even this may not be "safe" (Friberg, Ex. 29).
Temporary medical removal is an indispensable part of the cadmium standard for two major reasons. First, workers who have not already developed irreversible kidney damage can be protected by temporary medical removal. Second, more specifically in operations and industries where engineering controls cannot reduce airborne cadmium levels to the PEL and during the period when industries are in the process of implementing engineering controls, workers with higher exposures to cadmium will have to place increased reliance on respirators for protection. The protection afforded by respirators often will be less than would have been afforded by engineering controls and MRP may become necessary. Thus, MRP can provide additional protection when it is especially needed.
As indicated above, temporary medical removal is mandated in three sorts of cases. First, under paragraphs (l)(3)(ii)-(iv) and (l)(4)(iv), the employer must remove the employee whenever a physician, in his or her medical discretion, determines in a written medical opinion that the employee shall be removed. The requirement that the physician make such a determination is driven by biological monitoring results, but the determination itself may be based upon biological monitoring results, other evidence of illness, or any other reason deemed medically sufficient by the physician. However, as stated previously, it is not OSHA's intention that workers should be removed under the physician's discretionary removal authority simply because their biological monitoring results exceed the minimum trigger provided in paragraph (l)(3)(ii). Second, under paragraphs (l)(3)(iii)-(iv) and (l)(4)(iv), the employer also must remove the employee whenever:
(i) The employee's CdU exceeds 15 ug/g Cr; or CdB exceeds 15 ug/lwb; or the level of B(2)-M exceeds 1500 ug/g Cr and, in addition, the employee's CdU exceeds 3 ug/g Cr or CdB exceeds 5 ug/lwb, and these levels are confirmed as specified in paragraph (l)(3)(iii); or (ii) Beginning on January 1, 1999, the employee's CdU exceeds 7 ug/g Cr, or CdB exceeds 10 ug/lwb, or the level of B(2)-M exceeds 750 ug/g Cr and, in addition, the employee's CdU exceeds 3 ug/g Cr or CdB exceeds 5 ug/lwb, and these levels are confirmed as specified in paragraph (l)(3)(iv).
Thus, under paragraphs (l)(3)(ii)-(iv) and (l)(4)(iv) removal may be effected by a written medical determination in which the physician exercises medical discretion to decide whether to remove an employee. However, where the employee's biological monitoring results are confirmed to exceed the trigger levels set out in paragraphs (l)(3)(iii)-(iv) and (l)(4)(iv), that alone triggers mandatory medical removal, and there is no latitude within which the physician may exercise discretion.
The third case in which temporary medical removal is mandated is where the employee is exposed to cadmium above the PEL and a physician determines in a written medical opinion that the employee cannot wear a respirator (paragraphs (l)(6)(iii)-(iv) and (l)(11)(ii)). For any employee who is removed because of the employee's inability to wear a respirator, the employer under paragraph (l)(11)(i)(D) is required to provide follow-up medical examinations at least every six months until the examining physician in a written medical opinion determines that the employee either may be returned to his or her normal job or must be permanently removed from exposure to cadmium above the PEL. The follow-up examinations are to monitor the health status of the employee insofar as it may be relevant to the employee's ability to wear a respirator and to reassess that ability so that the decision to return the employee to his or her normal job or to permanently remove the employee from work with exposure to cadmium above the PEL can be made as expeditiously as is medically prudent.
For employees who are removed because they experience difficulty breathing during use of, or fit testing for, respirators, additional tests are required to medically evaluate the reasons for the employee's inability to wear a respirator, such as changes in cardiopulmonary function. For these workers, who were exposed to cadmium above the PEL prior to being found to be unable to wear a respirator, it is also prudent to monitor their possible overexposure to cadmium.
The specific requirements of MRP, set out in paragraph (l)(11) of this standard, are written to achieve all the purposes discussed above. Under paragraph (l)(11)(i), the employer must remove any employee from work where exposure to cadmium is at or above the action level on each occasion that the employee's relevant biological monitoring test results exceed any of the mandatory medical removal triggers specified in paragraphs (l)(3) or (l)(4) of the standard and on each occasion that a physician determines in a written medical opinion that the employee should be removed from such exposure. As stated above, the physician's determination may be based on biological monitoring results; evidence of illness, other signs or symptoms of cadmium-related dysfunction or disease; or any other reason, except inability to wear a respirator, deemed medically sufficient by the physician to indicate that the employee has a medical condition that places the employee at increased risk of material impairment to health from further exposure to cadmium at or above the action level.
The biological monitoring test results that provide the central criteria for removal are established in paragraphs (l)(3)(ii)-(iv) based on medical evidence that workers with results above these levels are at substantially increased risk of cadmium-induced illness and dysfunction. The levels that were selected as triggers for each of the progressively enhanced tiers of medical surveillance, and ultimately for medical removal, generally must be avoided to prevent an increasing risk of cadmium related dysfunction and disease. The decision to remove an employee with CdU, CdB or B(2)-M at or below the mandatory removal levels is left to the discretion of the examining physician because he/she is best able to make that judgment based upon all the available medical evidence concerning the particular employee. However, when the employee's biological monitoring results are confirmed to exceed these trigger levels, the accompanying risk of significant adverse effects to the employee's health is enhanced, and the decision to medically remove becomes mandatory.
In most cases in which a worker is removed for medical reasons, the standard provides for removal from work having an exposure to cadmium at or above the 2.5 ug/m(3) action level on any day. This limitation on the level of cadmium to which a removed worker can be exposed was selected for three reasons: first, to assure that the removed worker would not be exposed to cadmium at a level high enough to further increase the risk to his or her health; second, to assure that the level of cadmium to which the removed worker might be exposed would be low enough to facilitate a net decrease in the employee's body burden of cadmium, with the aim of restoring normal levels of cadmium in the measured compartments of the body, so that the employee could be returned to his or her former job status; and third, where cadmium-induced disease or dysfunction has already occurred, to minimize further progression of the existing condition. Nevertheless, OSHA recognizes that situations may arise in which removal of workers to jobs with airborne cadmium exposure just below the action level would be inadequate to protect the worker's health. These situations can and should be dealt with by the examining physician on an individual basis in the course of a thorough medical examination conducted pursuant to the standard. Although the standard embodies the judgment that, at a minimum, all removed workers must be removed from work having an exposure to cadmium at or above the action level, it does not restrict a physician from recommending actions more protective than the standard's requirements where necessary to protect the health of individual workers.
As stated above, under paragraph (l)(11)(i)(D), employees who are medically removed must be given follow-up medical examinations every six months until in a written medical opinion the examining physician determines that the employee either may be returned to his/her former job status or must be permanently removed from cadmium exposure at or above the action level. It is important that employees on medical removal receive semiannual medical examinations. Because cadmium is excreted in the urine, which must pass through the kidney, the burden of cadmium in the employee's kidney is likely to increase for a time while the employee is on medical removal. Therefore, it is imperative that the employee's health, and in particular the employee's kidney function, diet, smoking habits, use of medication, and water intake, be strictly monitored throughout the natural process of reducing the amount of cadmium accumulated in the employee's body.
In general, the medical basis for returning the employee effectively is a finding by the physician that the employee no longer has a medical condition that places him or her at increased risk of material impairment to health from exposure to cadmium at or above the action level. However, for employees who were removed because of abnormally high biological monitoring results, with the single exception set out in paragraph (l)(11)(v) which is discussed immediately below, no employee may be returned to a job where he/she will be exposed to cadmium at or above the action level until his/her biological monitoring results fall to or below the return trigger levels specified in paragraph (l)(11)(iv), that is, until CdU falls to or below 3 ug/g Cr, CdB falls to or below 5 ug/lwb, and B(2)-M falls to or below 300 ug/g Cr. These levels are below levels at which the standard requires the examining physician to consider discretionary removal. Return of a removed employee is generally not permitted until the employee's biological monitoring results have fallen to low levels in order to assure that workers who have been removed because of overexposure to cadmium are not returned to significant exposure to cadmium until their body burden of cadmium is sufficiently low.
However, in paragraph (l)(11)(v), the standard does provide one narrow exception to this requirement. In rare cases, where in the physician's professional opinion continued exposure will not pose an increased risk to the employee's health (e.g., the potential decrements to the employee's kidney function are not projected to be any greater if the employee were permitted to continue on the job than they would be if the employee were removed) and there are special circumstances making continued medical removal particularly problematic for the employee, the examining physician in a written determination may return a worker to his or her former job status despite what would otherwise be unacceptably high biological monitoring results. OSHA recommends that the physician consider the use of this narrow exception for particular employees only after two quarterly biological monitoring results have been obtained after medical removal (i.e., no sooner than six months after the worker has been medically removed due to elevated biological monitoring results). Six months will provide a minimum period of time during which a physician must try to determine if existing damage is cadmium related, and if so whether such damage is permanent. In cases where the employee is permitted to return to work under this exception, the employee should continue to be medically monitored as if he/she were still on medical removal until such time as the employee's biological monitoring results have decreased to or below levels of CdU of 3 ug/g Cr, CdB of 5 ug/lwb, and B(2)-M of 300 ug g Cr.
The purpose of this exception, which OSHA intends to be used with extreme care, is to provide some flexibility where it is reasonably clear that returning the worker to his/her normal job is unlikely to adversely affect the employee's health and the alternative to return is, for all practical purposes, much more drastic for the employee; e.g., termination of the employee from his job with loss of pension benefits. Depending upon the particular circumstances, a decision to return a worker with high biological monitoring results might be justified, for example, when an employee has been on medical removal for 18 months, is about to retire, and the time that the employee will continue to be occupationally exposed at or above the AL is very limited; e.g., a few months. When the physician does authorize return of the employee in such cases, the physician may require the employer to provide the employee with additional protection, such as a supplied air respirator operated in a positive pressure mode. In any event, the decision to return the employee should be made only after the physician has fully explained the relevant facts and prognoses to, and fully consulted with the employee.
As discussed above, under paragraphs (l)(6)(ii) and (l)(11)(ii), medical removal also is required whenever an examining physician determines in a written medical opinion that an employee cannot wear a respirator and must be removed from a job with exposures to cadmium above the PEL.
Under paragraph (l)(11)(i)(B), an employer who is required to medically remove an employee must do so regardless of whether at the time of removal a job is available into which the removed employee may be transferred. If no such job is available, the employer must, nonetheless, pay full MRP benefits to the employee even though the employee is effectively medically laid off. Initially, this might be costly to employers. However, after the initial adjustment period during which workers who were excessively exposed to cadmium prior to promulgation of this standard will have to be medically monitored and, where necessary, removed in accordance with the medical surveillance and MRP provisions of this standard, MRP costs should be quite low. The provisions of this standard requiring employers to control workplace airborne cadmium levels to the PEL, in conjunction with the tiered structure of enhanced medical surveillance and other ancillary provisions should prevent the vast majority of workers from being excessively exposed to cadmium. Consequently, on the one hand, employers who promptly come into compliance with the provisions of the standard should encounter very few workers who require temporary medical removal at any one time, and on the other, exposure levels in most jobs should be controlled to levels low enough so that removed workers may be transferred into those jobs. OSHA, therefore, expects employers to experience only a minimal economic impact from MRP after the initial adjustment period.
Paragraph (l)(11)(vi) deals with "voluntary" medical removals and limitations by employers. Where an employer, although not required by the standard to do so, removes an employee from exposure to cadmium or otherwise places limitations on the employee's exposure to cadmium because of the effects of cadmium exposure on the employee's medical condition, the employer must provide the employee with the same MRP benefits (MRPB) as if the removal been required under paragraph (l)(11). The purpose of this paragraph is to prevent employers from avoiding the requirements of paragraphs (l)(11) and (12) by voluntarily removing employees for medical reasons before those paragraphs would otherwise require removal and payment of MRP benefits. Without this provision regarding voluntary removal, MRP, MRPB and medical surveillance might be subverted by the actions of unscrupulous employers.
Paragraph (l)(12) of this standard deals with MRP benefits. Under that paragraph, the employer is required to provide up to 18 months of MRP benefits to a worker on each occasion that he or she is medically removed from exposure to cadmium in accordance with paragraph (l)(11). As stated above, OSHA is requiring that MRP benefits be provided in response to workers' understandable fears that participating in the medical surveillance program required by the cadmium standard otherwise might lead to a loss of their jobs and job benefits. Although MRPB cannot entirely eliminate that possibility (e.g., where a worker has suffered irreversible damage to his or her health that requires permanent removal from exposure to cadmium), workers will be protected for a considerable time from loss of income, job, seniority and all other employee rights and benefits due to temporary medical conditions that may require their removal from exposure to cadmium at or above the action level. Moreover, even for workers who must be permanently removed, MRPB protects the workers' wages and rights and benefits during the period needed to determine that permanent removal is required. Thus, MRPB largely removes an important disincentive to voluntary participation by employees in medical surveillance.
OSHA selected 18 months as the maximum period during which MRPB might have to be paid for several reasons. First, OSHA wanted to provide benefits for a period that was long enough so that the vast majority of removed employees who could be returned to their former job status would be able to be returned before their MRPB ran out. Second, the 18-month period for MRP benefits appears to have worked well in the lead standard (see 29 CFR 1910.1025 (k)(2)). Cadmium, like lead, is a heavy metal with a long half-life in the body.
OSHA believes that, with medical removal, elevated levels of CdU, CdB and B(2)-M can be reduced over time to safe levels in many employees who have not been so overexposed to cadmium that they have suffered resulting permanent damage to their health. However, how long it will take for employees with elevated levels to return to safe levels is not precisely known. The amount of time needed will depend upon three interrelated factors: the employee's current burden of cadmium or level of B(2)-M; the employee's rate of excretion of cadmium; and the extent of any continuing exposure to cadmium. The exact rate of natural excretion of accumulated cadmium from an employee's body, in turn, depends upon several factors, e.g., past and recent exposures, and body burden (Ex. 29). Since the half-life of cadmium in some compartments of the body is very long, and in most compartments is even longer than the half-life of lead in bone, i.e., 20 years (Ex. 8-668), OSHA has concluded that nothing less than the 18-month-MRPB period provided in the lead standard should be applied to cadmium exposed workers. This is a change from the cadmium proposal, which authorized a maximum of six months for MRP.
Based on its experience with MRP in practice in the lead standard, the toxicological similarities between lead and cadmium, and the best available evidence on cadmium, OSHA believes that most workers removed from significant exposure to cadmium who can be returned to their former job status because of "normal" biological monitoring results will be returnable within considerably less time than 18 months. According to De Silva, when exposures end, CdU and CdB levels fall during the first year (Ex. 8-716). Dr. Friberg stated that after cessation of exposure, cadmium concentrations in blood rapidly decrease with a half-time of two to three months (Ex. 29). This decrease is related to body burden. After the rapid decrease, CdB levels decrease more slowly depending upon recent and past exposures. Furthermore, in some cases a high urinary cadmium excretion may be seen after short-term exposures that have been very high, even without renal dysfunction (Ex. 29).
If examining physicians seek to prevent the onset of kidney disease by prudent early responses to protect workers, e.g., by temporarily removing a worker whose CdU level is well below, say, 10 ug/g Cr from exposure to cadmium at or above the action level, nearly all such workers should be returnable well within 18 months. For those workers whose levels have not fallen into the "normal" or safe range within 18 months, OSHA expects that continued temporary removal typically will serve no useful medical purpose since the damage done to their health is likely to be beyond restoration.
More generally, the medical determination as to whether a removed employee may be returned to his or her former job status can only be made after a medical examination, which the employer is required to provide. The employer must continue to provide MRP benefits until a final medical determination is made that either the worker can be returned to his or her former job status and the worker is returned or the worker is incapable of ever safely returning to his or her former job status and the worker is permanently removed by a written medical determination from exposure to cadmium at or above the action level.
Former job status refers to the position the worker would likely be occupying if he or she had never been removed. For example, if, but for a temporary medical removal, a worker would now be working at the same position held just before removal, then the employer must return the worker to that job. Otherwise, the employer may return the worker to a job that is consistent with whatever job assignment discretion the employer would have had if no removal had occurred.
The standard also provides in paragraph (l)(12)(iv) that the employer may condition the provision of MRP benefits upon the employee's participation in medical surveillance. Thus, the standard does not directly mandate worker participation in medical surveillance, but rather permits the employer to deny economic protection to employees who are unwilling to participate in medical surveillance.
This may constitute a modification of a similar provision in paragraph (k)(2)(iii) of the lead standard. In that standard, the employer is expressly authorized to condition provision of MRP benefits upon an employee's participation in follow-up medical surveillance while the employee is medically removed. The express authorization in the cadmium standard authorizes the employer to condition provision of MRP benefits on an employee's participation in medical surveillance provided pursuant to this standard, whether that surveillance is prior to or during medical removal.
OSHA provides this authorization for several reasons. First, as indicated, one of OSHA's primary purposes in requiring the employer to establish a medical surveillance program pursuant to this standard is to prevent occupational disease associated with exposure to cadmium. This can be most effectively accomplished when all employees participate in medical surveillance, which can provide early warning signals and thereby minimize the risk of disease. If an employer conditions the availability of MRP benefits upon an employee's participation in medical surveillance generally, the employee will have strong incentive to participate. Within the bounds of reason and what is lawful under the OSH Act, OSHA supports efforts to encourage and facilitate employee participation in medical surveillance.
Second, since the employer must bear the financial burden of medical removal, the employer has a legitimate interest in minimizing the need for medical removal. But, unless employees participate in medical surveillance, the employer may not be able to identify who among them may require additional protective measures to reduce their exposure to cadmium before medical removal is indicated. Thus, if an employee does not participate in medical surveillance, an employer may not learn that the employee's absorption of cadmium is approaching dangerous levels until, for example, the employee becomes symptomatic or learns from some other source that certain of his biological parameters are elevated. At that point, the employer may be left with no alternative but to medically remove the employee.
In authorizing the employer to condition provision of MPR benefits upon an employee's participation in the medical surveillance required by this standard, OSHA does not intend to authorize the employer to deny MRP benefits for insignificant or irrelevant lapses in such participation. The employee's actions should be assessed reasonably, in light of the goal of prevention of disease and the employer's interest in minimizing the need for medical removal. So long as the employee's lapses in participation do not frustrate the goal of disease prevention and the employer's interest in gaining early warning that an employee may need to be medically removed if steps are not taken to reduce the employee's absorption of cadmium, the lapses do not constitute grounds for denial of medical removal protection benefits. Thus, for example, if an employee did not show up once or twice for scheduled medical surveillance or even if the employee did not participate for a substantial period of time in medical surveillance, so long as the employee's participation was timely enough for the employee and employer to be on notice that the employee's biological monitoring results and/or other signs and symptoms are indicative of an increased risk of cadmium associated disease, the employer is not authorized to deny MRP benefits. The point is that the authorization provided by this paragraph is not intended to be used as an excuse to wrongfully deny employees MRP benefits.
In paragraph (l)(12)(ii) of the standard, the MRP benefits that the employer is required to provide are the "total normal earnings, seniority, and all other employee rights and benefits" of a removed or medically limited worker as if the worker had not been removed or otherwise limited. The purpose of this requirement is to assure that a removed worker suffers neither economic loss nor loss of employment opportunities due to the removal. Thus, for example, if a removed employee typically earned overtime pay on the job from which he or she was removed and would have continued to do so during the removal period, then MRPB must include the amount of that overtime as part of the employee's "total earnings."
Under paragraph (l)(13), a multiple physician review (MPR) mechanism is included in the medical surveillance provisions of the final cadmium standard, which gives workers the opportunity to obtain a second and possibly a third opinion regarding medical findings, recommendations or determinations made pursuant to the standard. Although MPR was not included in the proposed cadmium standard, OSHA in that proposal expressly stated that it believed MPR "might be necessary and appropriate" and requested comments on the matter (55 FR 4115). Written comments and testimony were received on this issue (Ex. 29, Tr. 6/6/90, pp. 110-111; Exs. 19-43; 123). Most of the testimony and comments supported the need for including MPR in the final cadmium standard.
"...it would be very difficult for the industrial physician to come up with wise decisions...in all circumstances....a multi-medical evaluation could be of value as soon as there is any...decision that is of consequence for the worker (Tr. 6/6/90)."
Opposition to MPR was based primarily on the assumption that the physician doing the examinations would be trained and experienced in occupational medicine and thus would be able to perform adequately (Ex. 77). However, if the first physician were not so trained and experienced, this commenter stated that MPR should be used as described by OSHA (Ex. 77, p. 6). OSHA agrees that MPR is needed in the final standard.
Under paragraph (l)(13), an employee may designate a second physician to review any findings, determinations or recommendations of an initial physician chosen by the employer and to conduct such examinations, consultations, and laboratory tests as the second physician may deem necessary. If a disagreement arises between the two physicians, the employer and employee are to assure that efforts are made to get the physicians to resolve their disagreement. However, should they be unable to agree, a third physician selected by the disagreeing physicians is authorized to review the evidence and conduct such tests, consultations and discussions as are necessary to resolve the disagreement. The employer is then required to act consistently with the decisions of the third physician, unless the employer and employee agree that the employer should act consistently with the decisions of one of the other two physicians.
OSHA recognizes the importance attached to medical surveillance by the OSH Act (Sec. 6(b)(5)) and views multiple physician review in the cadmium standard as an important element in the standard's medical surveillance program. That program, in turn, plays a crucial role in the operation of the standard's medical removal protection program. OSHA has three main reasons for providing MPR: First, to strengthen and broaden the bases for medical decisions made under the standard in situations where a worker questions the findings, recommendations, or determinations of an initial, employer-retained physician. Second, to increase employee confidence in the soundness of medical findings, recommendations and determinations made pursuant to this standard. And third, thereby, to increase employee acceptance of, and participation in the standard's medical surveillance program.
OSHA expects the provision of MPR, in interaction with other provisions of the cadmium standard, to strengthen and broaden the bases for medical decisions made under the standard. The requirement in paragraph (m) of the cadmium standard that the employer provide employees with appropriate information and training gives workers a basic opportunity to become knowledgeable about the nature and symptoms of the main cadmium-related diseases and about their rights under the cadmium standard. The availability of MPR, in turn, provides workers with an opportunity to put that knowledge to use through the informed exercise of their rights under MPR. MPR thus provides incentives to workers to take advantage of available health education and training to protect their own health. Consequently, when a worker questions the conclusions of the initial physician, a reasonable basis is likely to exist for seeking a second medical opinion.
Moreover, with the severe shortage of trained and experienced occupational physicians in this country and since cadmium-related diseases are not often encountered among persons not occupationally exposed to cadmium, it cannot be assumed that physicians performing examinations or consultations under the cadmium standard will provide error-free diagnoses. Under the medical surveillance program, physicians are often expected to exercise professional judgment and discretion, for example, in determining whether to remove a particular employee from exposure to cadmium at or above the action level. Although physicians are required by the standard to review its preamble and to be familiar with cadmium-related signs and symptoms of illness, these two provisions cannot guarantee that examining physicians will, in fact, be adequately trained or provide error-free diagnoses of cadmium-related diseases.
For many reasons, accurate medical determinations under this standard are vital for the proper functioning of the preventive medical removal protection program and more generally for the success of the medical surveillance program as a whole. The standard's PEL by itself may not be low enough to assure that all employees will be free of a risk to their health from occupational exposure to cadmium. In addition, many cadmium exposed workers will have had years of exposure to high levels of cadmium by the time the standard is promulgated. Furthermore, some cadmium related diseases may be reversible if detected at an early stage.
In the interest of accuracy, it would not be inappropriate to provide multiple physician review in all cases of medical surveillance under the standard where there might be any question about the validity of the initial physician's findings, recommendations or determinations. However, rather than requiring additional medical opinions in all such cases, which would be very expensive and potentially wasteful, OSHA is providing an opportunity for the person primarily affected by the initial physician's medical opinion, the employee/patient, to seek the opinion of another physician if the employee seriously questions the findings, determinations or recommendations of the initial, employer-selected physician.
OSHA's choice of the multiple physician review mechanism, as distinct from other mechanisms, is based in part on the common and increasing use of multiple physician review in the formation of medical determinations in the society at large. For example, MPR is frequently relied upon in the determination of a worker's eligibility for a disability pension and as a precondition for coverage in insurance policies to confirm certain diagnoses. Multiple physician review also has been incorporated into other standards promulgated by OSHA, such as the lead and benzene standards (29 CFR 1910.1025 and 1028, respectively).
The multiple physician review mechanism incorporated in the cadmium standard shares characteristics in common with many of these other examples of MPR. The worker has an opportunity to select a second physician if dissatisfied with the opinions of the first employer-selected physician, and if the two physicians disagree, the employee and the employer, through their respective physicians, may select a third physician to resolve the difference of opinion.
OSHA's second reason for providing employees with the opportunity for multiple physician review is to enhance employee confidence generally in the medical surveillance program and specifically in the soundness of medical determinations made pursuant to this standard. The cadmium standard's ability to prevent material impairment to worker health and functional capacity, particularly with respect to kidney damage in long term cadmium workers, will depend substantially on workers' trust and confidence in examining physicians. OSHA adopted the multiple physician review mechanism as a means of providing workers with an opportunity to obtain independent review of the findings, recommendations, and determinations of physicians whose opinions they do not trust.
Over time, this independent review, where implemented, is likely to show either that distrust of the employer-retained physician is unwarranted or that the employer should improve the quality of the employer-provided medical surveillance. Unless the employer fails to adequately respond, in either case confidence in medical surveillance and in the examining physician is likely to be increased. For example, if workers distrust a company doctor and therefore repeatedly seek other physicians' opinions, but the diagnoses of the other physicians repeatedly confirm the opinions of the company doctor, then workers will be much more likely to trust the employer-retained doctor in the future. On the other hand, if the choice of second and third physicians repeatedly results in medical determinations greatly at variance with the opinions of the employer-retained physician, then the employer is put on notice that the employer-provided medical personnel may need to be changed. In both cases, the multiple physician review mechanism will have served a beneficial purpose, either by dispelling an unfounded distrust of the company doctor or by correcting inadequate medical determinations while exposing major deficiencies in the employer's medical surveillance program and generating pressure on the employer to make needed changes. With employee involvement in MPR, resulting improvements in the medical surveillance program, and increased employee confidence in that program, OSHA expects increased employee participation in medical surveillance.
The inclusion of multiple physician review in the cadmium standard is not intended as criticism of the general medical community. Based on the rulemaking record, OSHA has no cause to conclude that most employer-retained physicians are not sincerely devoted to the good health of their workers. However, there is evidence in the record indicating that more than a few doctors retained by companies may not be sufficiently protective in light of recent developments concerning the potential carcinogenicity of cadmium and the levels of CdB, CdU and B(2)-M that are considered toxic or indicative of the existence, or high risk, of cadmium associated disease (Exs. 29; 77).
Multiple physician review is directed at problems presented by a minority of physicians, whose relevant medical knowledge may not be up to date, who may not be sufficiently sensitive to the health risks posed by excess exposure to cadmium, or who, in a limited number of cases, may not put the health of the workers first. In such cases, the opportunity for a second medical opinion is appropriate to protect the employee's health. On the other hand, where employer-retained physicians have a close doctor-patient relationship with employees and employees have confidence in the physicians' abilities and devotion multiple physician review will be seldom used (Swick, Tr. 7/18/90, p. 333).
The multiple physician review mechanism operates in a simple and straightforward fashion. It is applicable to all forms of medical surveillance provided under the standard after any initial examination or consultation provided by a physician chosen by the employer. If an employee's past, present, or future cadmium exposure is a relevant consideration in the examination or consultation being provided by the employer, then the opportunity for an additional medical opinion must be provided.
OSHA recognizes the value to employers and employees alike of the MPR mechanism operating in an expeditious fashion, and has established explicit requirements to that end. After an initial physician conducts an examination or consultation pursuant to the standard, the employer must promptly notify the employee of his or her right to seek a second medical opinion. This notification need be no more than an oral reminder of the existence and content of the right. After this notification has been given, an employer may condition its participation in, and payment for, MPR upon the employee, within 15 days after receipt of the employer's notification or receipt of the initial physician's written opinion, whichever is later, both informing the employer (orally or otherwise) that the employee intends to seek a second medical opinion and initiating steps to make an appointment with a second physician. These steps would include actually arranging an appointment or contacting a physician with the request that a referral to a specialist be arranged.
The standard contains no limitation on an employee's choice of a second physician, except the implicit requirement that the second physician, like the initial physician, must be licensed to practice medicine. Since cadmium can adversely affect numerous systems of the body, it would be inappropriate to limit the choice of doctors to any one specialty. Because it is in the employee's interest to choose an informed and competent physician, OSHA relies on employee self-interest to assure the value of the second opinion. Where, for example, an employee's disagreement with the initial physician's opinion revolves around a particular organ, e.g., the kidney, the employee would be likely to choose a specialist in that area. Where, however, the dispute revolves around several health effects or the employee cannot identify one specific problem, the employee would be likely to choose the general practitioner or internist most familiar with the employee's medical history and current health status. The employer must provide all relevant materials to the second physician.
The standard provides that the second physician shall review any findings, determinations or recommendations of the initial physician, and may conduct such examinations, consultations and laboratory tests as the second physician deems necessary to facilitate this review. While the standard does not expressly require the employer to supply the second physician with the same information that must be supplied to the initial physician, as well as the first physician's findings, determinations or recommendations, that is the intention. Indeed, the employer's obligation under paragraph (l)(9) of this standard to provide information to the examining physician is intended to extend beyond the first examining physician to all physicians who may be involved in multiple physician review or alternate physician determination under paragraphs (l)(12) and (13), respectively. All of these physicians, thus, would be provided with the same background information supplied to the initial physician and, as a result, would have as good an opportunity to assess the employee's health status.
If the second physician's findings, determinations, and recommendations are the same as those of the initial physician, then the multiple physician review process comes to an end. If, however, the opinions of the two physicians are in conflict, then the employer and the employee shall assure that efforts are made for the two physicians to resolve any disagreement. OSHA expects that the two physicians, as professionals, will communicate with each other to resolve their differences, but the standard requires the employer and employee to encourage such a resolution. In most cases, this professional interaction among peers should resolve any differences between the two physicians.
In cases where differences of opinion remain, these differences are likely to be genuine and substantial. Where the first two physicians have been unable to expeditiously resolve any differences of opinion with respect to an employee, then it is necessary for a third qualified physician to resolve the dispute. It is important that this third physician have the confidence of those concerned and be competent to resolve the dispute. Consequently, the standard provides that the third physician shall be designated by the employer and the employee jointly through their respective physicians. It is the responsibility of the employer and the employee to assure that a third physician is selected, but the selection is to be made by the two physicians. Since the third physician is chosen by the joint endorsement of the two physicians, confidence in the professional competence of the third physician should be assured.
The standard provides the third physician a full opportunity to review the findings, determinations, and recommendations of the two prior physicians by conducting such examinations, consultations and laboratory tests as the third physician deems necessary. The standard incorporates the expectation that the third physician will consult with the other two physicians. The third physician should provide a written medical opinion to the employer, which will normally operate as a final medical determination to resolve the disagreement between the other two physicians. The employer, then, is required to act in a manner consistent with the findings, determinations, and recommendations of the third physician, unless the employer and the employee reach an agreement that is otherwise consistent with the recommendations of at least one of the other two physicians.
Medical surveillance pursuant to section 6(b)(7) of the Act must be provided by employers without cost to employees. Since multiple physician review will be one means by which medical surveillance is provided to an employee, employers must bear the expense of this mechanism when it is used. In practice, and based partly on experience with MPR in other OSHA standards, OSHA does not expect the costs of MPR to be burdensome to employers. Employers will have substantial control over the frequency of its use. Where employers establish and administer medical surveillance programs that merit, engender, and maintain worker confidence, workers will see little or no need to seek second medical opinions.
As with many of the provisions of the final cadmium standard, the success of the multiple physician review mechanism will largely depend upon employers and employees acting in a reasonable manner and with good faith.
The requirement for MPR, however, is not intended to preclude an employer from establishing and implementing medical protocols for its employees that are expeditious and at least as protective. In paragraph (l)(14) a provision for alternate physician determination is expressly included in the standard. Under that paragraph, the employer and employee or designated employee representative may agree upon the use of any expeditious alternate physician determination mechanism instead of the multiple physician review mechanism provided. The only condition is that the alternate mechanism be no less protective of the employee's health than MPR. For example, the parties might decide in cases of dispute for an employee to go directly from an initial physician chosen by the employer to an agreed upon final physician, thus dispensing with the need for a second physician. Alternately, a jointly-agreed-upon physician might be used in the first instance without recourse to other physicians. Or, an employee might be given the opportunity to choose the final physician. OSHA encourages employers and employees to adopt medical determination procedures in which all parties have trust and confidence. Paragraph (l)(14) of the standard embodies this intention.
Under paragraph (l)(15) of this standard, the employer is required to provide the employee with certain information. The employer, within specified time periods, must provide the employee with a copy of the physician's written medical opinion, a copy of the employee's biological monitoring results, and, upon request, a copy of the information the employer is required to provide to the examining physician under paragraph (l)(9) of this standard. In addition, as discussed below in connection the summary and explanation of paragraph (n)(5), the employer is required to make the employee's medical records available upon request to other specified individuals.
OSHA believes that, for the good of the employee, facts, findings and decisions regarding the employee's occupational exposure to cadmium and medical status generally should be provided to the employee in written form. This is to assure that the employee is aware, and has a record of the results of exposure assessments and medical examinations that reflect his or her workplace experience. Making this information available to the employee will enable the employee to better understand the central facts concerning his occupational exposure to cadmium, including the extent of his cumulative exposure, the effect of that exposure on his health status, and the employee's rights under the cadmium standard. Being better informed, in turn, will enable the employee to more effectively participate in decisions about his/her health. It will also enable the employee to better inform physicians who, years after the employment has terminated, may need to know such facts to correctly interpret, and make proper decisions to protect or improve the employee's health status.
Under paragraph (l)(16), the employer is required to report on the OSHA Form No. 200, The OSHA Injury and Illness Log, any abnormal condition or disorder caused by occupational exposure to cadmium. This reporting requirement is consistent with the reporting requirements of the Bureau of Labor Statistics in the Department of Labor, as specified in Chapter (V)(E) of the Reporting Guidelines for Occupational Injuries and Illnesses. Although not included in OSHA's proposed regulation, OSHA indicated in that document that a provision for such reporting might be useful and appropriate (55 FR 4115).
Requiring employers to report occupational illnesses on the OSHA Form No. 200 and to post on that form for one month a year the annual summary of occupational illnesses is authorized under Sections (8)(c)(1) and (2), (8)(g)(2), and (24)(a) and (e) of the OSH Act and is mandated by 29 CFR Part 1904. The required reporting on the OSHA Form No. 200 and posting of the annual summary of the year's total from that form provides employers and employees with an additional opportunity to review the relevant record of illnesses among cadmium-exposed workers.
For the employer, for example, it is an opportunity to review all the cadmium-related removals during the year as a group, in order to ascertain whether there are patterns to the removals. For example, employers might use such information to determine the number of removals in various areas of the plant to see if the particular removals are correlated with higher exposures. In this way, employers may be able to identify and focus attention on certain areas of the plant where medical removals due to cadmium over-exposures are especially frequent. For the employer, it also is a reminder of those workers who require medical follow-up. For employees who have been removed for cadmium-related illness, this is an opportunity to confirm that the information provided to them individually is correct and has been reported to OSHA.
In addition, reporting on the log abnormal conditions and disorders that are occupationally caused and cadmium related will facilitate the development of occupational health statistics that are useful to the employer, the employee, and to OSHA, and in turn may facilitate the development of improved medical care. It will also provide OSHA with information and data helpful in assessing the effectiveness of the cadmium standard and in considering what, if any, modification should be made to the standard in the future. For all of these reasons OSHA believes that this requirement is pursuant to the OSH Act.
OSHA also believes that compliance with this requirement will be simple for employers. OSHA further believes that requiring the reporting of such removals may contribute to the prevention of more serious kidney damage.
Communication of Cadmium Hazards to Employees: Paragraph (m).
"Communication of Cadmium Hazards to Employees". These provisions incorporate many requirements from OSHA's Hazard Communication Standard (HCS) and address the issue of transmitting information to employees about the hazards of cadmium through the use of: (1) Signs, (2) labels, (3) material safety data sheets, and (4) information and training. Previous OSHA health standards generally included separate paragraphs on employee information and training and on signs and labels. The hazard communication provisions of this standard, consistent with the HCS, incorporate both of those areas, along with provisions on material safety data sheets (MSDS), into paragraph (m). The hazard communication provisions in this standard are very similar to those now being included in other OSHA health standards (e.g., paragraph (j), Benzene Final Standard, 29 CFR 1910.1028) and are basically the same as those in the proposed cadmium standard.
OSHA's HCS [(29 CFR 1910.1200) for general industry requires all chemical manufacturers and importers to assess the hazards of the chemicals they produce or import and to develop appropriate information about those hazards, which they are required to communicate in various ways to their own exposed employees and to relevant downstream employers, as specified under paragraphs (d)-(h) of the Hazard Communication Standard (29 CFR 1910.1200). Downstream employers, in turn, are required to communicate the information concerning the hazards of such chemicals in various ways to their own employees. The transmittal of hazard information to employees is to be accomplished by means of comprehensive hazard communication programs, which must include container labeling and other forms of warning, material safety data sheets and employee training.
Since the HCS is intended to comprehensively assess the potential hazards of chemicals and to communicate the needed information concerning hazards and appropriate protective measures to employees (52 FR 31877, August 24, 1987), OSHA includes paragraph (m) entitled "Communication of Cadmium Hazards to Employees" in this standard while referencing and requiring compliance with 29 CFR 1910.1200. In paragraph (m), OSHA also proposes additional particular requirements that are needed to protect employees specifically exposed to cadmium.
Paragraph (m) of this standard has been designed to be substantively as consistent as possible with the HCS requirements for employers. While avoiding a duplicative administrative burden on employers attempting to comply with the requirements of several different applicable OSHA health standards, the requirements nevertheless provide the necessary protection for employees through provisions for signs and labels, material safety data sheets, and employee information and training.
"Danger, Cadmium, Cancer Hazard, Can Cause Lung and Kidney Disease, Authorized Personnel Only, Respirators and Protective Clothing Required in this Area". The posting of these signs will serve as a warning to employees who may otherwise not know they are entering a regulated area. Such warning signs are required to be posted at all regulated areas, that is, whenever an employee is exposed above the permissible exposure limit. The signs are intended to supplement the training that employees are to receive under other provisions of paragraph (m), since even trained employees need to be reminded of the locations of regulated areas and of the precautions necessary to be taken before entering these dangerous areas.
For some work sites, regulated areas are permanent, because air cadmium exposures there cannot be reduced below the PEL by means of engineering controls. In those situations, the signs are needed to warn employees not to enter the area unless they are authorized, wearing respirators, and there is a need to enter. Regulated areas may also exist on a temporary basis, such as during maintenance and/or emergency situations. The use of warning signs in these types of situations is also important since a maintenance or emergency situation is by nature a new or unexpected exposure to employees who are regularly scheduled to work at or near these sites.
The standard requires that the signs comply with paragraph (f) of the HCS and specifies the wording of the warning signs for regulated areas in order to assure that the proper warning is given to employees. OSHA believes that the use of the word "Danger" is appropriate, based on the evidence of the toxicity and carcinogenicity of cadmium. "Danger" is used to attract the attention of workers in order to alert them to the fact that they are in an area where the permissible exposure limit is exceeded and to emphasize the importance of the message that follows. The use of the word "Danger" is also consistent with other recent OSHA health standards dealing with carcinogens. The standard also requires that the legend, "Respirators and Protective Clothing Required in this Area", be included on the warning sign. Although OSHA recognizes that some employees entering the regulated areas may not be exposed above the PEL, as an eight-hour time weighted average, many employees who are assigned to work in these areas may remain in these locations for long enough periods of time so that they would be needlessly overexposed to cadmium if they did not wear respirators and protective clothing.
In addition, it would be quite confusing and administratively complex to allow certain workers in the regulated areas to work without having to wear respirators while others were required to do so. Moreover, to the extent that some workers in regulated areas who may not be exposed on a particular day above the PEL are nonetheless required to wear respirators, this should further reduce any risk that may appear to remain at the PEL of 5 before the effects of the ancillary provisions are considered. To assure that all employees who work in regulated areas are adequately protected, it is necessary that the sign alert them to the need to wear respirators and protective clothing.
The standard also requires that warning labels be affixed to all shipping and storage containers (including bags) containing cadmium, cadmium compounds, or cadmium-contaminated items such as clothing and equipment. The labels must be in compliance with paragraph (f) of the HCS and must state: "Danger, Contains Cadmium, Cancer Hazard, Avoid Creating Dust, Can Cause Lung and Kidney Disease". Containers leaving the workplace must carry such labels. The purpose of this requirement is to assure that all affected employees, not only those of the primary employer, are apprised of the potentially hazardous nature of cadmium exposure where exposure could exceed the action level.
In addition to being consistent with the requirements of the HCS, these requirements carry out the mandate of section 6(b)(7) of the Act which requires OSHA health standards to prescribe the use of labels or other appropriate forms of warning to apprise employees of the hazards to which they are exposed.
In this final standard in accordance with the requirements of 20 CFR 1910.1200(g), OSHA also requires the manufacturer or importer of cadmium or cadmium compounds to develop and distribute MSDSs and requires downstream employers with employees potentially exposed to cadmium to maintain and provide access to a material safety data sheet (MSDS) for cadmium. OSHA feels that a properly completed MSDS, if readily available to employees, can serve as an excellent, concise source of information regarding the hazards associated with cadmium.
OSHA's main purpose in this section of the final standard, as stated in the Agency's recently promulgated HCS, is to assure that employees will receive as much information as they need concerning the hazards posed by chemicals in their workplaces. The MSDS assures that this information will be available to them in a usable, readily accessible and concise form. The MSDS also serves as the central source of information for downstream employers who must be provided with an MSDS if cadmium or a product containing cadmium in a toxic or potentially toxic form is produced and shipped to them. Lastly, the MSDS serves as the basic source of information on the hazards of cadmium essential to the training provisions of this standard.
Producers and importers of toxic substances have primary responsibility under the HCS to develop or prepare the MSDS. The manufacturer or importer is most likely to have the best access to information about the product and is therefore responsible for disseminating this information to downstream users of the material. For employers whose employees' exposure to cadmium is from products received from outside sources, the information necessary for a complete MSDS or the MSDS itself is to be obtained from the manufacturer and made available to affected employees. The requirements for the information that is to be contained on the MSDS are explained in detail at 29 CFR 1910.1200(g).
Paragraph (m)(4) of this cadmium standard requires employers to provide all employees who are exposed to cadmium with information and training on cadmium prior to or at the time of initial assignment to a cadmium exposed job and at least annually thereafter. A record shall be maintained of the contents of such programs (paragraph (n)(4)). The training program is to be in accordance with the requirements of the HCS paragraphs (h)(1) and (2), and to include the specific information required to be provided by that standard, as well as those items stipulated in paragraph (m)(4)(iii) of this standard. In particular, as several hearing participants have pointed out (Exs. 82, 84, and 107), training should explain how smoking cigarettes can increase an employee's total exposure to cadmium, either directly through inhalation of the cadmium in cigarettes or indirectly through ingestion of cadmium dust from the workplace that may accumulate on cigarette tips. Employers should also seriously consider whether to include information about smoking cessation programs in their training.
In addition, employees are to be provided with an explanation of the contents of Appendices A (Substance Safety Data Sheet, Cadmium) and B (Substance Technical Guidelines, Cadmium) to this standard. Employees also are to be informed where a copy of the final cadmium standard is accessible to them and to receive an explanation of the purpose and a description of the medical surveillance program required under paragraph (l) of this standard.
OSHA has determined during other rulemakings that an information and training program, as incorporated in the inclusive "Communication of Cadmium Hazards to Employees" paragraph of this standard, is essential to inform employees of the hazards to which they are exposed and to provide employees with the necessary understanding of the degree to which they themselves can minimize the health hazard potential. As part of an overall communication program for employees, training serves to explain and reinforce the information presented to employees on signs, labels, and material safety data sheets. These written forms of information and warning will be successful and relevant only when employees understand the information presented and are aware of the actions to be taken to avoid or minimize exposures.
Training is essential to an effective overall hazard communication program. Active employee participation in training sessions can result in the effective communication of hazard information to employees, which can stimulate workers to take conscientious protective actions on their jobs, which, in turn, can reduce the risk off occupationally-related illnesses and injuries.
The training provisions of this standard are in performance-oriented, rather than specific, detailed language. The standard requires training to be in accordance with the requirements of 29 CFR 1910.1200 and lists the categories of information to be transmitted to employees. However, it does not specify the ways that this is to be accomplished. The use of such performance-oriented requirements will encourage employers to tailor their training programs to the needs to their specific workplaces, thereby resulting in the most effective training program suitable for each specific workplace.
OSHA believes that the employer is in the best position to determine how the training he or she is providing is being received and absorbed by the employees. OSHA has therefore laid out the objectives to be met and the intent of training, to assure that employees are made aware of the hazards in their workplace and how they can help to protect themselves. The specifics of how this is to be accomplished are left up to the employer.
Comments by participants in the rulemaking on the hazard communication provisions of the proposed standard focused on three aspects of the proposed training requirements. The first is the need to train cadmium exposed workers about the dangers of smoking cigarettes. The second is the requirement that the employer provide training to all employees who are potentially exposed to cadmium, however low the level to which they might be exposed, instead of only to employees exposed above an action level. The third concerns the relationship between the training requirements in this standard and the MSDS provisions of the hazard communication standard.
The first concern is that all employees potentially exposed to cadmium be trained about the special hazards of smoking (Ex. 29). OSHA shares this concern and is requiring that employers train cadmium exposed employees about the additional exposure to cadmium from cigarette smoking. OSHA also suggests that employers seriously consider taking other steps, as well.
The second concern is that there should be an action level to trigger the employer's training requirement (Exs. 19-9; 19-36; Tr. 7/19/90, p. 284). OSHA disagrees with this position for several reasons. As demonstrated above, at very low levels of exposure cadmium is a probable human carcinogen and appears to cause kidney damage. If there is a threshold level below which exposure to cadmium does not cause kidney damage and below which it is not associated with lung cancer, that threshold must be extremely low, its exact level is unknown, and it undoubtedly varies from individual employee to individual employee. Moreover, OSHA's Hazard Communication (Haz Com) standard (29 CFR 1910.1200) already requires employers to provide employees with information and training on hazardous chemicals in the workplace without regard to any action level.
Nonetheless, for reasons set out above in the relevant sections of this preamble, OSHA has placed threshold exposure levels on the employer's obligation to implement engineering and work practice controls to achieve the PEL and to provide medical surveillance. However, since exposure to cadmium is not associated with any positive health effects and even at low levels has the potential for adverse health effects in some workers, OSHA believes that all potentially exposed employees should be informed about the nature of the hazard and about ways to minimize their exposure to it in order to facilitate their voluntarily taking preventive steps to protect themselves. In addition, training is needed at exposure levels below the action level since even at those low levels the possibility of skin or eye irritation caused by such cadmium exposure may exist.
Consequently, OSHA believes that it is good public health to require employers to train all employees potentially exposed to any level of cadmium. In imposing this obligation on employers OSHA is mindful of the fact that in most of the relevant workplaces the required training typically will involve adding elements to existing training programs and will not be very burdensome.
The third concern is that products containing less than .1% of cadmium, which are below the level that in the hazard communication standard would trigger the requirement that the producer or importer of a product containing a chemical identified as a carcinogen must develop and distribute companion MSDSs (29 CFR 1910.1200 (g)(2)(i)(C)(1)), might nonetheless produce downstream exposure levels above 1 ug/m(3) without the downstream employer being notified or even aware that his/her workers are exposed to cadmium (EEI, Tr. 7/19/92, pp. 19-20). This concern was articulated in response to OSHA's cadmium proposal, which proposed alternative PELs of 1 ug/m(3) or 5 ug/m(3) and alternative ALs of .5 ug/m(3) or 2.5 ug/m(3), respectively. However, this final standard adopts the higher of the proposed alternatives, 5 ug/m(3) as the PEL and 2.5 ug/m(3) as the action level. No commenter has claimed that products with a cadmium content of less than .1% can produce exposure levels at or above this action level or above this PEL.
Consequently the concern that employers who are not notified of the presence of cadmium by upstream producers or importers and are not aware of its presence in their workplace might still be subject to obligations triggered by cadmium exposures does not appear to be relevant to obligations triggered by the AL and PEL of this standard. The concern, thus, would be limited to the training requirement, which is the only obligation in this final standard that can be triggered by exposure to cadmium below the action level.
OSHA recognizes that there may appear to be some grounds for concern on this point. Under particular circumstances it might indeed be possible for an employer, while exercising due care, to be unaware of potential employee exposure to cadmium in the workplace and nonetheless vulnerable to citation for failure to train exposed workers under the cadmium standard. However, OSHA believes such situations will be very rare. The Agency is assured that in the vast majority of situations where workers are potentially exposed to cadmium, the employer will be aware or at least on notice of the existence of the hazard. The Agency is further assured that in most of the remaining situations, when inspections do occur, OSHA inspectors will weigh all the circumstances and generally refrain from citing unknowing employers who in good faith and in the exercise of reasonable care failed to provide required training. In any event, OSHA concludes that the small risk that an unknowing and blameless employer might be cited for failure to provide required training is outweighed by the need for the Agency to be conservative in protecting workers' health in the face of potential exposure to a highly toxic substance like cadmium.
Recordkeeping: Paragraph (n).
The recordkeeping provisions of this final standard are essentially the same as those in the cadmium proposal, which received little or no public comment (55 FR 4117). These provisions generally are similar to recordkeeping provisions in other OSHA health standards.
The standard requires employers to maintain exposure monitoring records and medical surveillance records. This requirement is in accordance with section 8(c) of the Act, which authorizes OSHA to require employers to keep and make available such records as the Secretary may prescribe "as necessary or appropriate for the enforcement of this Act or for developing information regarding the causes and prevention of occupational accidents and illnesses." The recordkeeping provisions of this standard are also in keeping with the regulation governing access to employee exposure and medical records (29 CFR 1910.20).
Medical and monitoring records are also maintained for employee disclosure and are designed to provide valuable information to both the employee and the employer. The medical and monitoring records required by this standard will aid the employee and his/her physician in determining whether or not treatment is needed for occupational exposure to cadmium and what level of treatment is necessary. Also, the employer benefits by keeping these records, since the information will enable the employer to better ensure that employees are not being over-exposed to cadmium; such information may alert the employer that steps must be initiated in order to reduce exposures.
The standard requires that records be kept of the results of environmental monitoring and the contextual information required by paragraph (d) of this standard to determine the airborne concentration of cadmium to which an employee has been exposed. Specifically, records must include the following information:
(a) The date, duration, and results in terms of an 8-hour TWA of each sample taken;
(b) The name, social security number, and job classification of the employee monitored and of all other employees whose exposures the monitoring is intended to represent;
(c) A description of the sampling and analytical methods used and evidence of their accuracy;
(d) The type of respiratory protective device, if any, worn by the monitored employee and by any other employees whose exposures the monitoring is intended to represent; and (e) a notation of any other conditions that might have affected the monitoring results.
The standard requires that exposure monitoring records be maintained for each measurement taken. The monitoring and record may represent the exposure of more than one employee if representative sampling, as described in paragraph (d), is conducted. In that case, the record should clearly provide the same information about the employees whose exposures the monitoring is intended to represent as is required by paragraph (n) of this standard for the monitored employee.
A provision for the use of objective data in place of initial monitoring is included in this standard in paragraph (d)(2)(iii). Objective data are defined in paragraph (n)(2)(i) as information demonstrating that a particular product or material containing cadmium cannot release dust or fumes in concentrations at or above the action level even under conditions of worst-case release. Employers might use data from an industry-wide survey to estimate maximum cadmium exposure levels that could occur if that survey pertains to workplace conditions that, to the extent relevant and significant, are all very similar to those in the employer's worksite. Employers may also use laboratory product test results to demonstrate that airborne concentrations must be below the action level.
In addition to being required to keep records on monitoring of employee environmental exposure levels, the employer is required by paragraph (n)(3) to establish and maintain an accurate medical surveillance record for each employee to whom the employer must provide medical surveillance under paragraph (l) of this standard. As indicated above in this preamble, medical records are necessary for the proper evaluation of the employee's health. Furthermore, medical records, like exposure monitoring records, are necessary and appropriate both to the enforcement of the standard and to the development of information regarding the causes and prevention of occupational illnesses.
The records of the employee's prior medical and work history are useful to the examining physician in the examination at termination of employment as an aid in determining the status of an employee's health and in identifying adverse health effects associated with cadmium exposure. Good medical records, including the record of the examination at termination of employment itself, also can be useful to the Agency and others in enumerating illnesses and deaths attributable to cadmium, in evaluating compliance programs, and in assessing the accuracy of the Agency's risk estimates. Such records are useful, as well, to assess the adequacy of the standard in preventing disease. Provisions for collection of such information, including medical examinations at the end of employment, have been included in other OSHA standards (e.g., Arsenic, Benzene, and Lead Final Standards).
The standard requires that exposure records be kept for at least 30 years ((n)(1)(iii)) and that medical records be kept for duration of employment plus thirty years ((n)(3)(iii)). It is necessary to keep these records for extended periods because of the long latency period commonly associated with carcinogenesis. Cancer often cannot be detected until 20 or more years after first exposure. The extended record retention period is therefore needed because diagnosis of disease in employees is assisted by, and in some cases can only be made by, having present and past exposure data as well as the results of present and past medical examinations.
The employer is also required to maintain records of an employee's cadmium-related training for one year beyond the last date of employment of that employee. Employers are required to certify that employees did participate in such training. Certification of training must contain the name of the employee, date training completed, and signature of employer or provider of the training.
The standard provides for access to exposure and medical records that basically is in accordance with 29 CFR 1910.20, OSHA's standard for "Access to Employee Exposure and Medical Records" under paragraph (n)(5)(i). That standard applies to records required by specific standards, such as this cadmium standard. In addition, it is OSHA'S intention that the employee should have similar access to exposure and medical records that are voluntarily created by an employer. Employees, their designated representatives, and former employees are, in general, allowed unrestricted access to all relevant exposure monitoring records. More limited access is provided for medical records. Access to all the employee's medical records required to be kept under paragraph (n)(3) of this standard is provided to the subject employee, to anyone having the subject employee's specific written consent, and, after the employee's death or incapacitation, to the employee's family members. In addition, OSHA and NIOSH retain access to both kinds of records, but the agencies' access to personally identifiable medical records is subject to agency rules of practice and procedure that have been published at 29 CFR 1913.10 (see 45 FR 35384) and to the limitations to protect confidentiality incorporated in 29 CFR 1910.20.
Upon written request, the employer is required to provide the records within 15 days to those entitled to them. The transfer of employee exposure monitoring and medical records is to be in accordance with the provisions of paragraph (h) of 29 CFR 1910.20. If an employer ceases to do business and there is no successor employer, the employer is to notify NIOSH and transmit the records to the Director of NIOSH for retention, if requested.
The purpose of requiring that certain medical information be made available only to someone with the employee's specific written consent is to assure that confidential medical information not be disseminated without a conscious and specific decision by the employee authorizing it. It is also to assure that persons or organizations appropriately authorized by the employee shall have access to such information. This might include, for example a union, which, thereby, might be put on notice of potential health hazards in the workplace that might adversely affect the employee and other similarly situated workers.
Observation of Monitoring: Paragraph (o)
This standard contains provisions for employee observation of exposure monitoring. This is in accordance with section 8(c) of the OSH Act, which requires that employers provide employees and their representatives with the opportunity to observe monitoring of employee exposures to toxic substances or harmful physical agents. Observation procedures are set forth that require the observer, whether employee or designated representative, to be provided with the personal protective clothing and equipment that is required to be worn by employees working in the area. The employer is required to assure the use of such clothing, equipment, and respirators, and is responsible for assuring that the observer complies with all other applicable safety and health procedures.
Dates: Paragraph (p).
The standard will become effective on December 14, 1992. All obligations imposed by the standard commence on the effective date unless otherwise noted. All obligations that do not commence on the effective date shall be complied with as soon thereafter as possible and in any event no later than the start-up date, which is a compliance deadline.
Because small businesses frequently have fewer resources for interpreting and implementing complex requirements to protect their workers, and in order to implement an outreach program and to provide technical assistance to employers with small businesses [nineteen (19) or fewer employees], start-up dates for certain provisions are later for these establishments.
The requirements for initial exposure monitoring (paragraph (d)(2)) and for handwashing facilities (paragraph (j)(1)(ii)) must be completed no later than 60 days after the effective date of the standard (120 days for small businesses). The requirements for regulated areas (paragraph (e)) and respiratory protection (paragraph (g)), must be completed no later than 90 days after the effective date of this standard (150 days for small businesses). The requirements for initial medical examinations (paragraph (l)(2)), and employee information and training (paragraph (m)(4)), must be completed no later than 90 days after the effective date of this standard (180 days for small businesses).
In addition, written compliance programs (paragraph (f)(2)) shall be completed and available for inspection and copying no later than one (1) year after the effective date of the standard. Engineering and work practice controls (paragraph (f)(1)) generally are required to be fully implemented no later than two (2) years after the effective date.
Hygiene and lunchroom facilities must be completed as soon as possible and in any event no later than 1 year after the effective date. As stated above, handwashing facilities, permanent or temporary, must be provided in accordance with 29 CFR 1910.141 (d)(1)-(2) as soon as possible and in any event no later than 60 days after the effective date of this section (120 days for small businesses).
With the exception previously stated for small businesses, nearly all of the start-up dates established in this standard are conventional. They have been developed out of OSHA's experience with similar standards and closely parallel start-up dates in other health standards (e.g., Lead Final Standard). The start-up dates in this final standard also closely parallel those in the proposed cadmium standard (55 FR 4128).
Some minor modifications have been made to the proposal. For example, the effective date is 90 days after publication, rather than the proposed 60 days. OSHA decided to give employers slightly more time to comply with the standard. In addition, if employers do not now provide adequate handwashing facilities, they are required to provide adequate temporary or permanent facilities within 60 days after the effective date (120 days for small businesses). The proposal did not include any requirement for prompt provision of handwashing facilities. This omission was pointed out by a commenter, who correctly noted that portable sinks and other hygiene facilities can be readily provided (Ex. 19-7). OSHA agrees. It is important that workers be able to wash off any cadmium from their hands and faces before they eat, smoke and leave work. This will reduce their overall exposure to cadmium and limit the carrying of cadmium dust into their cars and homes. OSHA believes that most employers already provide handwashing facilities and that the cost of providing such facilities, where they are not already provided, is relatively modest.
There is, however, one more substantial change to the proposed start-up dates in this final standard. A provision that would have allowed employers in certain circumstances to delay constructing all hygiene facilities for nearly three years is deleted. During that period, employees would have been deprived of these facilities. The deletion is made for the same reason that the Agency in the final standard is requiring the prompt provision of handwashing facilities. OSHA is convinced that these facilities are needed to protect the health of workers' exposed to cadmium above the PEL.
Several commenters representing management requested, without providing adequate supporting evidence or data, that OSHA defer the start-up dates (compliance deadlines) for various provisions. One, for example, asked that the start-up date for initial monitoring be 180, not 60, days after the effective date. The only reason provided for this request was the possible shortage of industrial hygienists (Ex. 19-9). OSHA declines to defer this start-up date for several reasons. First, there is no evidence of, or reason to believe there will be a shortage of industrial hygienists. Second, since the standard now sets the effective date at 90, instead of 60, days after promulgation, all employers will have more time to prepare for compliance. In addition, small businesses will have 120 days after the effective date for initial monitoring. This should allow an employer concerned about a possible shortage of industrial hygienists to contact one well in advance of the compliance deadline and arrange for timely initial monitoring.
Another commenter argues that an extended period of time is needed to design, construct and learn how to operate engineering controls, that start-up dates for all other provisions of the standard should be set after the deadline for compliance with the engineering and work practice controls requirement, and that time be provided for phasing in biological and air monitoring sampling and MRP (Ex. 19-40). As stated above, OSHA believes that the compliance times provided in the staggered start-up dates are reasonable and that no additional time is needed to come into compliance with the various requirements. Employers generally will have two years from the effective date of the standard to implement engineering controls to achieve the PEL and to achieve the SECAL. Deferring all other start-up dates until after the deadline for achieving the PEL or SECAL would allow employees who are currently exposed to excessive levels of cadmium and not otherwise adequately protected, for example, by an effective medical surveillance program, to continue to be unnecessarily exposed and unprotected.
The Dry Color Manufacturers Association (DCMA) argues that time also is needed to standardize biological and environmental monitoring methods and to set up a laboratory accreditation program to assure the quality of analysis of monitoring results (Exs. 120, 19-40). OSHA agrees that some time is needed for employers to familiarize themselves with the requirements of medical surveillance, to develop appropriate methods to comply with the requirements, especially with regard to biological monitoring, and to locate laboratories with demonstrated proficiency in the relevant analyses. As a guide to employers and others, OSHA has devoted considerable effort to developing a non-mandatory program concerning standardization of specimen collection and handling and laboratory proficiency which is incorporated in Appendix F. The Agency believes employers who follow this protocol, or other comparable criteria that are at least as comprehensive and strict, will be assured that employee monitoring results are accurate and reliable and will generally be in compliance with paragraph (l)(1)(iv) of the standard.
OSHA is aware that a number of laboratories already have demonstrated their proficiency in analyzing CdU and CdB and that the Phaedabas kit is widely accepted as assuring reasonably accurate and reliable measurements of B(2)-M. (See Health Effects Section V.) Consequently, OSHA sees no reason why employers will be unable to comply with the provisions relating to biological monitoring by the relevant start-up date, which is 90 days after the effective date of the standard (180 days for small businesses). The Agency is considering establishing mandatory provisions for laboratory proficiency and accreditation.
Appendices: Paragraph (q).
The final cadmium standard contains six appendices that are designed to assist employers and employees in implementing the provisions of this standard. Appendix C is incorporated as part of this standard and imposes additional mandatory obligations on employers covered by this standard. Appendices A, B, D, E and F are non-mandatory, except that Appendices A, D, and F must be reviewed by physicians in order for them to be able to medically evaluate employees covered by this standard regarding any cadmium-related illnesses. Also, questions 3-11 and 25-32 of Appendix D are required as part of the limited medical examination that is required prior to the use of a respirator. Otherwise, these appendices are not intended to add to, or detract from any obligation that the cadmium standard otherwise imposes.
The Appendices that are included in the standard are: Appendix A - Substance Safety Data Sheet, Cadmium Appendix B - Substance Technical Guidelines, Cadmium Appendix C - Qualitative and Quantitative Fit Testing Procedures Appendix D - Medical and Occupational History with Reference to Cadmium Exposure (suggested format) Appendix E - Sampling and Analysis Appendix F - Protocol for Laboratory Standardization for Biological Monitoring for Cadmium
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