Regulations (Preambles to Final Rules) - Table of Contents Regulations (Preambles to Final Rules) - Table of Contents
• Record Type: Occupational Exposure to 4,4' Methylenedianiline (MDA)
• Section: 9
• Title: Section 9 - IX. Summary and Explanation of the Standard for General Industry

IX. Summary and Explanation of the Standard for General Industry

Paragraph (a). Scope and Application.

(a)(1) OSHA's final standard applies to all "occupational exposures"

to MDA with the specific exceptions set forth in the scope and application section and would apply to all workplaces in all industries, except for construction, where MDA is produced, released, stored, handled, used, or transported, and over which OSHA has jurisdiction.

OSHA developed a separate standard for the construction industry, 1926.60. The two standards, general industry and construction, do, however, cover all industries covered by the Act. The general industry standard covers all activities and operations including ship repair and rebuilding, manufacturing, secondary processing, and downstream use of MDA. Employees of the Construction Industry are covered by the construction standard. Construction activities are defined in 29 CFR 1910.12(b) as work for construction, alteration and/or repair, including painting and decorating.

As noted above, ship repair and shipbreaking activities are covered by the general industry standard. OSHA believes the provisions of the general industry standard are appropriate for the operations involving MDA which will occur on ships. (See the new 29 CFR 1910.19(i) that is promulgated below.) (a)(2) This paragraph contains exclusions for workplaces that process, handle, or use products containing MDA where initial monitoring data show that the product cannot release MDA at or above the action level and where no "dermal exposure to MDA" can occur (see discussion under Paragraph (b), Definitions, as to what constitutes "dermal exposure to MDA"). The criterion for exemption under paragraph (a)(2) requires monitoring data that show that the material is incapable of releasing airborne MDA at or above the action level under the expected conditions of processing, handling or use. The material also must not be a material that results in "dermal exposure to MDA," as defined. Paragraphs (a)(8) and (e)(5) are exceptions to this exemption. Since the exemption is based on initial monitoring, paragraph (a)(8) requires that these monitoring records be maintained. Similarly, paragraph (e)(5) requires additional monitoring when changes occur that might affect employee exposure.

This exemption and the underlying rationale for this exemption were adopted by OSHA from the Mediated Rulemaking Committee's recommendations (Exhibit 9). During the Committee's deliberations, various situations were discussed pertaining to this exemption which the Committee believed should be excluded from the requirements of any final regulations. For example, MDA based epoxy resins are often shelved in hardware stores. Unless the containers are broken, these resins pose no hazard for employees stocking shelves etc. In this situation, it is clear that handling these materials does not result in exposures above the action level nor will dermal contact with the MDA material occur. A second example involved the mechanical transportation of MDA through an automated piping system. Unless the pipe ruptures, the Committee believed that it was not possible for employees to be exposed to MDA transported in this manner. Thus dermal exposure was not expected. Therefore, the Committee believed that this type of situation should also be excluded from the standard.

In both of the examples described above, the Committee only addressed worker exposure which resulted from either ambient exposure above the action level or the potential for dermal exposure to non-airborne forms of MDA. Consideration was not given to any dermal exposure which might result from ambient exposure and subsequent "fall out" (airborne particles or vapors settling on the skin). It was the Committee's belief that dermal absorption hazards resulting from this "fall out" of airborne MDA had already been adequately addressed by establishing very low permissible exposure limits and action level. OSHA fully concurs with the Committee on these points. The exemption, under paragraph (a)(2), therefore, is available when two conditions exists, i.e. exposure above the action level does not occur and "dermal exposure to MDA," as defined, is not possible.

(a)(3) This paragraph allows the employer to rely on objective data as the basis for an exemption when the data indicate that MDA is not capable of being released ambiently and where no "dermal exposure to MDA" can occur. OSHA believes that the primary and intermediate users will be in the best position to test their products and to supply the necessary objective data. The final standard would not require downstream employers to generate their own objective data on the MDA levels likely to be released from a product if they can obtain it from producers or other processors. There was no objection to the proposed allowance of the use of "objective data" as exemption criteria. Thus, the final standard contains this provision as specified in the proposed rule.

(a)(4) The final standard also exempts the storage, transportation, distribution, or sale of MDA in intact containers sealed in such a manner as to contain the MDA dusts, vapors, or liquids, except for the provisions of 29 CFR 1910.1200 as incorporated into this standard and the emergency provisions of this standard. Containers are covered by the Hazard Communication standard, 29 CFR 1910.1200 (52 FR 31852; Aug. 24, 1987), which requires, in conjunction with the MDA standard, labeling containers to indicate that they contain MDA (a suspect carcinogen), employee training specifying what to do if the container was opened or broken, and supplying material safety data sheets to users/employees.

The basis for this exemption is that sealed containers are unlikely on a regular basis to leak sufficient MDA to expose employees over the action level or pose a dermal exposure problem. The labeling and training provisions of the Hazard Communication standard provide sufficient protection in those situations where a container breaks so that employees will know how to handle and clean up a spill safely. The intention of this exemption is to cover most warehouses, distributors, supply rooms, and similar operations where chemical containers are stored, transported, or sold, and not normally opened. However, operations where the containers are opened and the contents used or tested would be covered by the standard because of the possibility of exposure in excess of the action level or dermal exposure.

Other than the concerns over the omission of the 0.1 percent exclusion, there was no comment on this paragraph. The 0.1 percent exclusion is addressed in relation to paragraph (a)(6) and that discussion applies to this paragraph as well.

(a)(5) This paragraph contains provisions establishing a separate standard for construction and excluding construction activities from the scope of the general industry standard.

(a)(6) This paragraph was not contained in the NPRM. It establishes a de minimis exclusion for MDA mixtures or materials which contain MDA in concentrations of less than 0.1 percent by weight or volume. OSHA implicitly incorporated a de minimis exclusion in its NPRM as recommended by the Committee. In OSHA's notice of hearing found at 55 Federal Register 2101 (January 22, 1990), OSHA clearly states,

The exclusion found in the proposed MDA rule, although not explicit, implicitly states that a 0.1 percent exclusion will be part of the MDA rule.

OSHA was guided in adopting this exclusion by the data furnished by the Mediated Rulemaking Committee. In the recommendations rendered by the Committee, data were provided which indicated that worker exposure to mixtures or materials of MDA containing less than 0.1 percent MDA did not create any hazards other than those expected from worker exposure beneath the action level (Ex. 9). Additionally, the requirements found in 29 CFR 1910.1200 (d)(5) state,

...that the mixture shall be assumed to present a carcinogenic hazard if it contains a component in concentrations of 0.1 percent or greater which is considered to be a carcinogen...

Thus, having given consideration to both the Committee's recommendations and OSHA's Hazard Communication standard provisions, OSHA decided in the NPRM to be consistent with the Hazard Communication requirements. This exclusion was the basis for the majority of the concerns expressed by the commenters to the NPRM. As a result of these concerns OSHA, in its Federal Register notice of January 22, 1990, invited testimony on,

. . .the appropriateness of expressly establishing a 0.1 percent exclusion by weight or volume for all operations involving mixtures containing MDA from the proposed regulation. (Id.)

In addition, several commenters and hearing participants recommended a de minimis percentage exclusion of 0.1 percent be adopted, thus reflecting the Hazard Communication standard (Lockheed, Ex. 11-22; United Technologies, Ex. 11-23; Monsanto, Ex. 11-26; United States Air Force, Tr. II-5; etc). On the other hand, no data were furnished by any of the hearing participants or in the post-hearing comments which would suggest that establishing a 0.1% exclusion, as suggested in the hearing notice, would not be appropriate. Thus, OSHA has added to the scope and application section of both the general industry and the construction standards a paragraph adding this percentage exclusion.

(a)(7) The final standard contains an exemption for "finished articles containing MDA" (See discussion under Definitions) (a)(8) This paragraph requires that the employer appropriately document the information which supports any exemption, and the employer must maintain a record of this information. There was no comment made to the provisions contained in this paragraph. The final standard contains this paragraph as originally proposed.

Paragraph (b). Definitions.

Paragraph (b) of the final MDA standard for general industry defines a number of terms used in the standard. In some instances, the definitions are consistent with those found in other OSHA standards, e.g., "Director," "Assistant Secretary," and "Authorized person". However, certain other terms will be discussed to clarify their meanings in this standard.


OSHA establishes an "action level" of one-half of the established TWA in the final standard. The purpose of the action level is to relieve the burden on employers by providing a cut-off point for required compliance activities under the standard.

The statistical basis for determining the action level is discussed in connection with several other OSHA health standards (see, for example, Acrylonitrile, 43 FR 4794). In brief, although all measurements on a given day may fall below the permissible exposure limit, some possibility exists that on unmeasured days the employee's actual exposure may exceed the permissible limit. Where exposure measurements are above one-half of the permissible exposure limit, i.e. the action level, the employer cannot reasonably be confident that the employee may not be overexposed. (Leidel, N.A. et al., "Exposure Measurement Action Level and Occupational Environmental Variability." DHEW, PHS, DCD, NIOSH, DLCK (August 1975)). Therefore, requiring periodic employee exposure measurements to begin at the action level provides the employer with a reasonable degree of confidence in the results of the measurement program.

In the absence of a demonstrated safe level of exposure for a carcinogen, it is appropriate to begin some protective actions, for example monitoring provisions, shower requirements and medical surveillance, at one-half the PEL or, in the case of MDA, 5 parts per billion. Establishing an action level serves such a purpose, as well.


The final standard includes a definition of an emergency. Emergency is defined to mean any occurrence such as, but not limited to, equipment failure, rupture of containers, or failure of control equipment which results in an unexpected and potentially hazardous release of MDA. Sections of the final standard that include provisions to be met in case of emergencies include respiratory protection, medical surveillance, and employee information and training.

There was some comment on the NPRM regarding the definition of an emergency situation. Objectors argue that the courts have restricted the requirement for implementing an emergency plan to circumstances where the probability of harm is present rather than requiring emergency provisions be triggered by the potential for a hazardous release. They argue that the definition contained in the proposed rule, because of the over inclusive nature of the term "potential," requires that an emergency plan, including alarms, evacuation, and all other elements specified in 1910.38, be implemented in situations which are questionably emergencies.

General Dynamics (Ex. 11-9), on the other hand, reads the definition of emergency very narrowly to mean that only primary manufacturers need establish emergency programs.

OSHA reviewed all of the comments regarding the definition of an emergency and believes that the language recommended by the MDA Mediated Rulemaking Committee and proposed by OSHA in the NPRM is the appropriate language. OSHA acknowledges that every spill or leak does not constitute an emergency situation. The exposure to employees must be significant and pose a hazard. OSHA believes that this is a performance oriented provision relying on judgement and that it is not possible to specify detailed circumstances which constitute an emergency. Further, OSHA believes that the definition as proposed allows the employer sufficient flexibility in exercising judgement as to which situations constitute an emergency. In addition, the emergency provisions of this standard are consistent with similar provisions of other OSHA toxic substance standards (See for example, 29 CFR 1910.1003-.1016, 1910.1017(i), 1910.1045(i), and 1910.1047(h).

Employers must provide emergency plans and employees must be trained to implement these plans. The definition is promulgated as proposed.


OSHA's final regulation also defines "employee exposure" to mean that exposure which would occur if the employee were not using a respirator or personal protective equipment. The employee's exposure measurements would be made without regard to any use of personal protective equipment. OSHA believes that exposure monitoring is not a single-purpose activity. It is necessary to know employee exposure levels without the use of respiratory protection or personal protective equipment to evaluate the effectiveness of engineering and work practice controls and to determine whether additional controls must be instituted. In addition, monitoring is necessary to determine which respirator, if any, must be used by the employee. This definition is consistent with OSHA's previous use of the term "employee exposure" in other health standards.


The final standard exempts "finished articles containing MDA" from the regulation. A "finished article containing MDA" is defined as a manufactured item: (i) which is formed to a specific shape or design during manufacture; (ii) which has end use function(s) dependent in whole or part upon its shape or design during end use; and (iii) where applicable, is an item which is fully cured by virtue of having been subjected to the conditions (temperature, time) necessary to complete the desired chemical reaction.

As discussed below, OSHA is basing this action on testimony by rulemaking participants that end use articles, including cured articles, do not present a hazard with respect to exposure to MDA; on quantitative data evaluating the extent to which unreacted residual MDA remains on or within finished articles; and on experience gained by OSHA during development of its Hazard Communication standard (48 FR 53280).

The Air Force, in its testimony, recommended "...exempting finished articles from the standard, and the definition of 'finished article' should include fully cured products, that is, those that a user may only have to drill assembly holes or finish sand and this goes back to the hazard communication standard" (TR. 2-5). The Air Force further commented that:

In our testimony we recommended finished articles be exempted from the MDA ruling [sic] and further recommended the definition of finished article included cured products. Our definition of a cured product is any item which has been subjected to the conditions [necessary] to complete the desired chemical reaction. The purpose of this definition is to exempt those composite parts which only require final machining (limited to debarring and final hole drilling) but not exempt prepreg materials which can be further cut and shaped to form a final product. (Ex. 35).

Exemption for cured, MDA products was also supported by Dr. JoAnne Pigg, a technical health professional member of the OSHA Mediated Rulemaking Advisory Committee:

I recommend that all cured materials utilizing MDA including adhesives, encapsulates, coatings, etc., in addition to composites, be exempted from requirements of the proposed standard. It is agreeable that finite, but undetectable levels of MDA can exist in those materials, but no health hazards from employee exposure exist. (Ex. 20).

With respect to the question of why curing eliminates concern over MDA exposure, Brunswick testified that:

During the curing process the MDA is cross linked chemically with the epoxy resin or polymerized with the polyamide resins. The cross linking results in a formation of a solid epoxy product. The raw components, MDA, epoxy resins and polyamide resins lose their identity in the process that is not reversible. The resulting mass of cured resin is considered to be a non-hazardous product as defined by the EPA (TR. 1-194).

The CMA pointed out that "...curing procedures and times and temperatures are all designed ... to... [result in products that are]...essentially MDA-free," and "...if they are improperly cured...then they're not going to have the physical properties that the supplier was trying to impart to them." (TR. 1-205).

Sampling data submitted to the record substantiates the assertion that it is appropriate to exempt cured MDA materials from the standard. Data were submitted by Sandia National Laboratories (Ex. 20B) on three cured materials: an epoxy containing 25 percent MDA, a polyurethane containing 10 percent MDA and a polyamide formulation containing 4 percent MDA. Wipe sampling performed on the products after full completion of the curing processes revealed no free or unreacted MDA at the detection method limits of 0.2 micrograms per hundred square centimeters. Sandia indicated that these materials were tested for unreacted surface MDA because ". . .when it's cured it certainly . . . would be physically bound inside but we wanted to make sure there was nothing on the outside. . ." (Tr. 1-185).

In addition to surface sampling for MDA, Sandia analyzed dust generated from drilling of a finished cured circuit board derived from the polyamide formulation containing 4 percent MDA. Analyses revealed the dust to be free of MDA at the limit of detection of 2 ppb (Tr. 1-182). Rhone-Poulene, Inc. testified that ". . .final products produced from our resins do not contain detectable MDA. For example, test efforts to detect free MDA in copper clad cured laminates to a detection level of 0.0001 percent had been unsuccessful." (Tr. 1-134).

Finally, the Air Force cited data showing ". . .swipe samples averaging 0.4 micrograms per 100 centimeters squared used in an epoxy putty which air cures." (Tr. 2-7). Although measurable surface MDA was detected on this material, the Air Force submitted calculations illustrating the relative degree of health hazard associated with such exposure. The Air Force estimated that a surface contamination of 2,400 micrograms per 100 square centimeters would be required in order to pose a health risk equivalent to that of the proposed 10 ppb airborne exposure. The Air Force asserted that it is unlikely that cured products would ever have surface contamination approaching this level. (Ex. 35).

Based on comment and data in the record, such as that cited above, OSHA concludes that it is appropriate to exempt finished articles containing MDA, including cured products, from the requirements of the MDA standard. OSHA is convinced that finished articles do not present a health hazard to employees to the extent that it is necessary to regulate such hazards under the MDA standard. OSHA believes that the health benefits derived from compliance with this rule will best be served by obligating employers to focus resources on control of employee exposure to MDA forms and uses only in those instances where a health hazard exists.

The specific language in the definition of "finished articles containing MDA" is derived from two sources. Items (i) and (ii), discussed further below, are taken from the definition "article" in the Hazard Communication standard which defines items exempt from that rule. Item (iii) has been adopted from language recommended by the Air Force (Ex. 35) for use in identifying what a cured product is (e.g. ". . .subjected to the conditions necessary to complete the desired chemical reaction.") OSHA believes that the language in item (iii) is sufficiently explicit that employers know at what stage their products can be considered fully cured for the purposes of this regulation. The term ". . .subjected to the conditions. . ." clearly means that the article must experience its full curing time at the temperatures designed to effectuate the curing process. The article will be considered cured if the desired chemical reaction has been completed as a result of it having been subjected to the specified curing time(s) and temperature(s). Items (i) and (ii) under the definition are derived from OSHA's Hazard Communication standard, as was suggested during the rulemaking hearing (Tr. 2-6). The Hazard Communication standard exempts any "article" which, defined in part, is a ". . .manufactured item: (i) which is formed to a specific shape or design during manufacture; [and] (ii) which has end use function(s) dependent in whole or in part upon its shape or design during end use." For example, pre-pregs, by their very design and application, would ordinarily not be exempted by the "Finished Article" criteria. (See Ex. 11-24, Ex. 19A, Tr. 1-136.) The preamble to the Hazard Communication standard explains the rationale underlying this exemption as follows:

Several commenters suggested that OSHA exempt "articles" from the scope of the standard. The purpose of this exemption is to ensure that items which may contain hazardous chemicals, but in such a manner that employees won't be exposed to them, not be included in the hazard communication programs. Examples of such items would be nuts and bolts or tools. The exemption has been added to the final standard and a definition was added as well. It was further suggested that OSHA adopt the definition for "article" used by the Environmental Protection Agency (EPA) under the Toxic Substances Control Act (TSCA). OSHA found that the definition used by EPA was appropriate for this standard in part. The EPA definition in part is essentially as follows: "article" means a manufactured item: (i) which is formed to a specific shape or design during manufacture; and (ii) which has end use function(s) dependent in whole or in part upon its shape or design during end use. 48 FR 53280

For the same reasons cited under the Hazard Communication standard, parts (i) and (ii) of EPA's definition of "article" is being adopted by OSHA under the MDA standard.


The final standard requires the employer to take certain protective actions where employees, engaged in the handling application or use of mixtures or materials containing MDA, are subject to dermal exposure to MDA. "Dermal exposure to MDA" can occur with any of the following non-airborne forms of MDA: (i) liquid, powdered, granular, or flaked mixtures containing MDA in concentrations greater than 0.1 percent by weight or volume; and (ii) materials other than "finished articles" containing MDA in concentrations greater than 0.1 percent by weight or volume. In situations where employees handle, apply or use any MDA mixtures or materials as defined above, dermal exposure to MDA is considered to occur. The agency believes that correlating dermal exposure with handling, applying or using specific forms of MDA removes the confusion that has arisen from using such terms as "likelihood of dermal exposure." Simply put, dermal exposure to MDA is assumed to occur when employees handle, apply or use any MDA falling under the definition of "Dermal exposure to MDA." Where such exposure occurs employers must do the following: provide affected employees with appropriate protective equipment, as required under paragraph (i) of this section; establish regulated areas, as required under paragraph (f) of this section; establish hygiene practices and lunch areas, as required under paragraph (j) of this section; and implement a medical surveillance program for affected employees as required under paragraph (m) of this section.

OSHA believes that the protective measures prescribed under the paragraphs cited above are necessary in order to minimize the adverse health effects associated with dermal exposure to MDA. OSHA's risk assessment analyzed the risk associated with dermal exposure and found that a 20 fold increase in risk could be prevented by not allowing dermal contact with MDA. MDA is easily absorbed through the skin at the rate of 2 ug/cm(2) per hour. In addition, recent studies by El-hawari (Ex. 1-251) indicate that the absorption of MDA peaks 5 hours after the end of the work shift and that 80 percent of the substance is cleared from the body within 24 hours of exposure. It is difficult to correlate the amount deposited on the skin with a biological indicator, such as the amount found in the urine, because of the characteristics of MDA absorption and elimination in humans. MDA easily enters the body through the skin. Once deposited on the skin absorption continues although the worker may have long since left the work place and the apparent exposure area. Once absorbed into the body the chemical is rapidly eliminated so that using a biological indicator, such as urine measurement, may not detect the apparent exposure. All in all, MDA can be considered a chemical with poor biological warning properties or biological indicators of exposure. The best protective measures which can be taken are to prevent skin contact and subsequent absorption by regulating the handling, applying or using of forms of MDA which can result in "dermal exposure to MDA." This will in turn reduce both the risk of cancer and the potential for hepatotoxicity.


Regulated areas are defined as areas where MDA concentrations exceed or can be reasonably expected to exceed the permissible exposure limits or where employees are engaged in the handling, application, or use of MDA that can result in "dermal exposure to MDA."


The final standard includes a definition of MDA. Included in the definition are the salts of MDA. The rationale for including the salts in the definition of MDA was not challenged in the response to the NPRM. Thus the compounds covered by the proposed definition remains the same in the final standard.

The NPRM definition contained an exclusion for finished products which is now part of the scope and application section of this final rule.

Paragraph (c). Permissible exposure limit (PEL).

The final standard will limit exposure to MDA by establishing a PEL of 10 ppb as an 8-hour TWA. In addition, OSHA believes that airborne exposure will be further reduced by establishing a STEL for airborne MDA exposures of 100 ppb determined in any 15-minute sampling period (See discussions at 52 FR 26858 and 54 FR 20702). The requirements contained in the final standard are supported by OSHA's findings that occupational exposure to MDA under current occupational conditions poses a significant risk to the health of employees and that the final standard can achieve a substantial reduction in that risk. The permissible exposure limits proposed by OSHA have not been challenged by the rulemaking participants. Thus, the requirements in the final standard remain the same as proposed.

While the permissible exposure limits were not challenged, many of the commenters suggested a biological indicator as a permissible exposure limit. Specifically, the commenters recommend that OSHA adopt an acceptable level of MDA which can be detected in the urine as a permissible exposure limit. Additionally, they contend that the absence of any detectable level of MDA in the urine or a level below the established standard should be used to exclude an employer from coverage of the standard. This concept is similar to that of using the action level as a point below which compliance with specific provisions of the standard is not required. Dr. James Hathaway, the corporate medical director for Rhone-Poulenc Inc. states this position very precisely:

OSHA (should) include in the standard an option for employers to demonstrate lack of likelihood of significant dermal exposure through biological monitoring. Consistent findings at the end of the shift, end of work week levels of MDA in the urine of less than 160 micrograms per liter should exempt employers from provisions of the standard, other than the ones that would relate to an accidental exposure where, you know, I think it's logical then that certain things would have to be done. (TR. I, 132)

Dr. Hathaway made this recommendation based on earlier calculations which he had made in which he estimates the 5 ppb action level could be comparable to MDA urine levels of 160 ug/l. Thus, since the exposures were nearly comparable, he suggests that the risks were also comparable. (TR. I, 117-133) The Boeing Co. through the written comments of James Vinson also urged that OSHA make use of biological monitoring as a means of exempting the employer from the requirements of the standard. He states:

The regulation provides an exemption from the requirements where the likelihood of dermal exposure does not exist. It does not, however, provide a mechanism of determining the likelihood of dermal exposure. It is therefore proposed that OSHA require medical monitoring if the "no likelihood of dermal exposure" exemption is to be used. Urine MDA below 100 ppb, for example, would indicate no likelihood of dermal exposure and would allow an exemption from the requirements (Ex. 14-7).

The use of urinary monitoring results to establish a biological PEL was considered by the Mediated Rulemaking Committee. The Committee's discussions were provided to OSHA as well as its recommendations (Ex. 9). OSHA summarized the Committee's recommendations at 54 FR 20694 as follows:

It is difficult to correlate the amount deposited on the skin with a biological indicator, such as the amount found in the urine. There are many confounding factors which lead to these findings. Firstly, through absorption rates it is apparent that MDA easily enters the body. Secondly, once deposited on the skin absorption continues although the worker may have long since left the work place and the apparent exposure area. Thirdly, once absorbed into the body the chemical is rapidly eliminated so that using a biological indicator, such as urine measurement, may not detect the apparent exposure. All in all MDA can be considered a chemical with poor biological warning properties or biological indicators of exposure.

During the hearings, the Chemical Manufacturer's Association pointed out that the sampling protocol for MDA urinary monitoring is not sufficiently developed at this time to demonstrate a correlation between levels of MDA or its metabolites in the urine and disease development. Furthermore, they contend that there is no correlation between amount of metabolite found in the urine and the total body burden which can be attributed to this form of exposure. (Tr. II, 173) OSHA believes that the recommendations made by the Committee and the testimony provided by CMA regarding the use of biological monitoring are sound and for these reasons is not including a biological PEL in the standard. OSHA, on the other hand, agrees with NIOSH that biological monitoring has some practical application in the standard setting process. NIOSH states at TR I, 25-28 that:

In regard to biological monitoring, NIOSH recommends biological monitoring to assess the degree of protection offered by the use of recommended protective clothing and equipment, and to assess the effectiveness of other controls such as work practices...It may be noted that biological monitoring assesses exposure by all routes...dermal, inhalation and ingestion.

OSHA also recognizes that the recommendations made by NIOSH regarding the use of biological monitoring in the standard setting process are the same recommendations made by the Mediated Rulemaking Advisory Committee, i.e., biological monitoring can be effectively used to determine the effectiveness of personal protective clothing and equipment, engineering controls, or work practices. OSHA recognizes as did both these groups that if a positive urine sample is found and the worker is wearing personal protective equipment that some or all of the equipment is not operating effectively. The employer armed with this information can then attempt to determine the source of the exposure. Although OSHA does not require that the employer conduct biological monitoring to determine the effectiveness of engineering controls, work practices, or personal protective clothing or equipment, the employer can voluntarily use biological monitoring to supplement the safety and health program. OSHA will continue to review any technological developments regarding biological monitoring for MDA exposure. Additionally, OSHA will consider changes to the standard that involve the establishment of a biological PEL if evidence sufficient for regulatory purposes becomes available.

Paragraph (d). Emergency Situation.

OSHA believes that the available health data suggest that elevated short-term exposure to MDA should be viewed with concern. OSHA believes that an unexpected high exposure must be viewed as an emergency situation. The final standard requires that a written plan be developed where there is a possibility of an emergency and that written procedures be developed for alerting employees in the event that an emergency occurs.

The standard provisions also include a requirement to alert employees other than those who have the potential to be directly exposed in an emergency situation. Such employees may be employees from neighboring work sites who may inadvertently approach the emergency site. They may also include employees from other work shifts or employees who may be later exposed to work surfaces or equipment contaminated as a result of the emergency.

OSHA also requires the development of a written plan for each workplace where there is a possibility of an emergency. The plan shall include the elements prescribed in 29 CFR 1910.38, "Employee emergency plans and fire prevention plans."

OSHA believes that the performance language of the emergency situation paragraph will give employers the flexibility to choose any effective method of alerting employees, including communications systems, voice communication, or a bell or other alarm. OSHA believes that emergency plans are necessary and must be made a part of every standard.

In response to the NPRM, some of the commenters expressed concern with the difficulties expected from implementing the emergency provisions of the standard. United Technologies (Ex.11-17) commented that emergency plans should only be required when there is a reasonable probability of MDA release in an emergency situation. They contend that the broadness of the term "possibility" makes every situation a potential emergency and thus becomes economically prohibitive. They commented that changing the term "possibility" to "probability" makes it easier to determine what is an emergency and when planning is required.

Many other commenters suggested that OSHA amend the requirement by changing the term "possibility" to "probability." The Brunswick Company states:

"Possibility" is an open-ended term that is defined in a legal term as presenting unlimited liability. "Probability" limits the scope of the intent of the requirements for the need to develop emergency plans to define parameters. The ideal legal terminology would be to include "reasonable probability" in the wording of the regulation to specify the development of an emergency plan which requires alarms and evacuation plans.(Ex. 15-4)

The basis for their contentions is that in small operations, such as those conducted by the Brunswick Company, the use of a full-scale emergency plan does not seem warranted. Further they urge OSHA to establish some action levels or criteria for developing and implementing an emergency plan.

United Technologies (Ex. 11-17) further states that the Courts have held that OSHA cannot require employers to abate the mere possibility of hazard but that there must be a reasonable probability of harm. Further they state that almost any situation can present the possibility of an emergency but it is difficult to imagine an emergency involving pre-pregs that is likely to present a significant risk to employees. Therefore, they argue, to be consistent with the Court's interpretation, the word "possibility" in this paragraph should be changed to "reasonable probability."

In addition, Chemical Manufacturer's Association (CMA) commented that an emergency plan should be required where there is a reasonable possibility of an emergency. (Ex. 11-13).

OSHA reviewed these written comments and finds that supportive evidence was not furnished which suggests that changing the term possibility to probability would facilitate compliance without compromising the benefits afforded the worker through these emergency planning provisions. Additionally, no hearing participant provided information supportive of United Technologies contentions. Finally, since United Technologies did not appear as a hearing participant, OSHA was unable to discover through cross-examination what, if any, probative evidence exists to support such a change.

OSHA, however, has the written recommendations of the Mediated Rulemaking Committee and the supportive rationale for the provisions contained in the NPRM. George Robinson, representing the IAM, testified during the Mediated Rulemaking Committee deliberations on the appropriateness of using the term "possibility" to trigger the emergency situations provisions. He provided the Committee with his experiences regarding workers who died as a result of the lack of emergency planning (Ex. 9). He felt that the broadest term, e.g. possibility, must be used when describing an emergency situation. His testimony convinced the entire Mediated Rulemaking Committee and subsequently OSHA when the NPRM was developed. OSHA agrees with the Committee's findings and, for the reasons stated in those recommendations, has adopted the term "possibility" as part of the emergency planning requirements.

Other commenters expressed concerns with what they believed to be a requirement to have two sets of duplicate written plans. Specifically, McDonnell Aircraft Company (Ex. 11-6) provided a written submission which stated that the requirements for two written plans, 1910.1050 (d) and (g)(2) are not necessary. They were referring to the requirement to have (1) a written emergency plan and (2) the requirement to develop a written plan for compliance with the PEL. The two requirements do not overlap. As previously mentioned, OSHA relied on the recommendations of the Mediated Rulemaking Committee in adopting the provisions contained in the NPRM. The rationale in support of a written emergency plan can be found in Exhibit 9, the Committee's recommendations. No evidence was provided by McDonnell Aircraft to support its assertions. Furthermore, in their written submission, they acknowledge that hazardous chemicals are present in most large manufacturing facilities and in abundant supply and diversity. Given the abundant supply and diversity expressed by the commenter, it hardly seems inappropriate to have a written plan which identifies the chemical and the emergency procedures. Furthermore, OSHA notes that the emergency provisions contained in the final standard are consistent with what OSHA has required in other standards. In light of the above, OSHA promulgates the emergency requirements as proposed.

Paragraph (e). Exposure Monitoring

Section 6(b)(7) of the Act (29 U.S.C. 655) mandates that any standard promulgated under section 6(b) shall, where appropriate, provide for monitoring or measuring employee exposure at such locations and intervals and in such manner as may be necessary for the protection of employees.

OSHA believes that it is appropriate for employers to measure employee exposure to MDA for the following reasons. First, exposure monitoring informs the employer whether the employer's legal obligation to keep employee exposure below the permissible exposure levels is being met. Second, exposure monitoring evaluates the effectiveness of engineering and work practice controls and informs the employer whether additional controls need to be instituted. Third, exposure monitoring is necessary to determine whether respiratory protection is required at all and, if so, which respirator is to be selected. Fourth, Section 8(c)(3) of the Act (29 U.S.C. 657) requires employers to notify promptly any employee who has been or is being exposed to toxic materials or harmful physical agents at levels which exceed those prescribed by an applicable occupational safety or health standard, and to inform such employee of the corrective action being taken. Finally, the results of exposure monitoring constitute a vital part of the information which must be supplied to the physician and may contribute information on the causes and prevention of occupational illness.

The final standard requires that the employer determine the exposure for each employee exposed to MDA. It is not necessary to provide separate measurements for each employee. If a number of employees perform essentially the same job under the same conditions, it may be sufficient to monitor only some of such employees to obtain data that are representative of the remaining employees. Representative personal sampling for employees engaged in similar work and exposed to similar MDA levels can be achieved by measuring that member of the exposed group reasonably expected to have the highest exposure. This result would then be attributed to the remaining employees of the group.

In many specific work situations, the representative monitoring approach can be more cost-effective in identifying the exposures of affected employees.

Because of the nature of the MDA exposure hazard, it is necessary that the scope of the final standard be as broad as possible to protect potentially exposed employees. However, many employers will be required only to perform initial monitoring to determine employee exposures. If the results of initial monitoring demonstrate that an employee's exposure to MDA is below the action level, the employer is allowed to discontinue monitoring and other activities under this provision of the standard for that employee. OSHA established this provision to reduce the burden on employers, while providing them with an objective means of determining whether they must take additional steps for compliance with the standard.

The final standard also contains provisions for periodic monitoring. The more frequent the measurement, the higher the accuracy of the employee exposure profile. Selecting an appropriate interval between monitoring efforts is a matter of judgment. Where exposure measurements are determined to be above the permissible exposure limits, the employer is required to monitor every 3 months. Where exposure measurements are above the action level but at or below the PELs, monitoring is required only at 6 month intervals. Additional monitoring is also required for a particular job position if any changes in production, processes, control measures, or personnel result in new or additional exposure to MDA. The redetermination of employee exposure is necessary to assure that the most recent results accurately represent existing exposure conditions. This is necessary so the employer may take appropriate action such as instituting additional engineering controls or providing appropriate respiratory protection.

The final standard also contains provisions for visual monitoring of exposed skin areas. The employer would be required to make routine inspections of the face, hands, and forearms of employees potentially exposed to MDA. If the inspection reveals yellow staining or other abnormalities associated with dermal exposure to MDA or if the employee attests to such abnormalities elsewhere on the employee's body, the employer shall send the employee to a medical professional for evaluation.

If the employer determines that the employee has been exposed to MDA the employer shall:

  (a)  Determine the source of exposure;
  (b)  Implement protective measures to correct the hazard; and
  (c)  Maintain records of the corrective actions in accordance
       with paragraph (n) of this section.

Many of the commenters presented testimony regarding the difficulty anticipated from implementing the visual monitoring requirements. The testimony was in three general areas: establishing responsibilities for the employer which are non-performable, invasion of privacy associated with the employer conducting visual monitoring of workers' skin and the specificity of the yellow staining.

Regarding the first issue, non-performable responsibilities, Westinghouse Electric Corporation (Ex. 11-11) argued that the requirement in the proposed rule to make routine inspections of employee dermal areas potentially exposed would be difficult to do. They contend that this requirement would make the first line supervisor a diagnostician. Furthermore, they contend that if the first line supervisors are not medically experienced, they can not be adequately trained to examine the skin surfaces sufficiently to detect exposure from MDA or any other dermal conditions. General Dynamics (Ex.11-3), although not concerned with the non-performability aspects of this provision, argued that some guidelines on what constitutes an employee skin inspection (presumably signs of yellow or red-itchy cracked skin) are necessary.

OSHA believes that the first line supervisor can conduct visual monitoring. OSHA is guided in making this decision by the recommendations made by the Mediated Rulemaking Committee. In the rationale provided by the Committee, it is clear that the first line supervisor is responsible only for examining the skin and looking for abnormal conditions such as yellow staining, red- cracked skin, browning of the finger tips, or whatever can be noticed by a simple visual inspection (Ex. 9). It should be noted that the purpose of this requirement is to determine whether or not personal protective equipment should be worn by the worker and, if so, is effective. The first line supervisor needs only to detect a change and then the worker must be referred to a physician for follow-up and determination. The Committee's rationale was that visual monitoring should be the first line of defense used when exposure to a skin absorbable substance is apparent. OSHA agrees with the Committee's rationale and has not been provided with any conflicting evidence. Thus, the requirement for the employer to conduct visual monitoring remains in the final standard.

Regarding the second issue, invasion of privacy, McDonnell Douglas (Ex. 11-6) stated that the visual monitoring requirements must delicately avoid invasion of privacy. They state:

It must clearly state that the employer may inspect face, hands, and forearms, and send the employee to a medical professional if other areas of contamination are suspected or attested to by the employee.

OSHA agrees that the privacy aspects of conducting dermal monitoring must be strictly adhered to. OSHA believes that if an employer follows the recommendations given by McDonnell Douglas as stated above that workers privacy will not be invaded. For example, the hands, face, forearms or in general the exposed areas of the body can be viewed without removing any clothing. The employer can examine the hands to determine if MDA exposure has occurred. The employee is capable of identifying staining on other parts of the body and should be referred to a physician for follow- up. During the Committee's deliberations, one of the employer groups presented data which indicated that yellow staining of lower body parts had been noted in his work force. The question of conducting visual monitoring in this instance was discussed at length for this particular situation. The Committee agreed and OSHA agrees with the Committee's conclusions that the best thing to do in this situation was to refer the worker to the appropriate medical personnel for follow-up.

Once the determination has been made that skin contact has occurred the appropriate corrective actions must be taken. Thus, the visual monitoring requirements contain the obligations of the employer for conducting this type of monitoring.

Many of the commenters stated that pure MDA does not produce yellow staining but that the staining results from handling of specific MDA mixtures. The Department of Energy (Ex. 11-8) contended that:

Visual monitoring of exposed body areas needs further consideration. Often meta-phenylene diamine (MPDA) is present in MDA liquid mixtures. While MDA alone does not stain skin or clothing significantly, MPDA stains both skin and clothing much more intensely. Thus with MDA-MPDA mixtures there could be considerable visible staining of skin and clothing resulting in unwarranted alarm if MDA is the major concern.

OSHA agrees that these concerns of the hearing participants are well founded. However, OSHA did not propose the provisions to conduct visual monitoring of workers' skin based solely on the belief that yellow staining could be used as a positive indicator of exposure. Instead, it was OSHA's view and that of the Committee that if a worker was wearing personal protective clothing, e.g. gloves, that dermal contact to whatever chemical was being handled should not occur. Therefore, if such exposure did not occur, then any noticeable changes in the skin, be it yellow stain, redness, cracked hands, etc. should not occur. OSHA believes, however, that yellow staining can be used as one of the indicators of exposure. This view is based on OSHA's analysis of a control study which reported that MDA produced yellow staining (Ex. 9). Later, during the MDA hearings, an additional study, conducted by the same examiner, was presented which indicated that it was not pure MDA but instead a mixture which caused yellow staining. While OSHA now agrees that yellow staining may result from exposure to a MDA mixture, OSHA also recognizes that MDA skin exposure can occur without skin staining. What remains apparent is that if there are noticeable changes to the skin and the worker is wearing personal protective equipment, these changes may be the result of the failure of the personal protective clothing to prevent exposure. The fact that visual monitoring helps to make this determination is the reason that this provision was recommended by the Committee, included in the NPRM, and is now part of the final standard.

Paragraph (f). Regulated Areas

The final standard requires that the employer establish regulated areas where MDA concentrations exceed or can be reasonably expected to exceed the permissible exposure limits or where employees are engaged in the handling, application, or use of MDA that can result in "dermal exposure to MDA." The regulatory text in the final standard was modified to conform to the definition of regulated area (See 52 FR 26857).

The final standard requires that regulated areas are to be demarcated in any manner that minimizes the number of employees exposed to MDA within these areas. To increase the performance-orientation of the standard and minimize recordkeeping, no detailed requirements were specified regarding the demarcating of an area. Unauthorized employees are restricted from entering the regulated areas. Employees working in regulated areas are required to wear the appropriate type of personal protective equipment and are prohibited from activities such as smoking and eating. Other purposes of this section are to designate those areas where precautionary signs are to be posted and to designate areas where employees may be subject to three-month monitoring when their exposure is above the PEL.

Regulated areas are required where airborne exposures exceed or can reasonably be expected to exceed the PEL and where dermal exposure to MDA can occur. Establishing regulated areas at all worksites where the potential exists for exposure above the permissible exposure limits is a regulatory approach that has been adopted by OSHA in many occupational health standards. This approach covers areas within worksites where there are frequent leaks, or where exposures may be of high concentration but of short duration, e.g., maintenance operations. Where only dermal exposure to MDA can occur, a regulated area shall be established where employees are engaged in routine or non-routine processes requiring the handling, application, or use of MDA. OSHA recognizes that where the potential for dermal contact and inadvertent exposure to non-airborne forms of MDA is great, a mechanism to prevent incidental exposure of employees not actively engaged in the process is very much needed. The purpose of a regulated area is to ensure that employers make employees aware of the presence of MDA and attempt to restrict access. By limiting access, the number of employees inadvertently splashed and subsequently exposed to MDA can be minimized.

The establishment of regulated areas is an effective means of limiting the risk of exposure to as few employees as possible. This is consistent with good industrial hygiene practice when exposure to a toxic substance can cause serious health effects. Access to the regulated areas is restricted to "authorized persons"; that is, those persons required by their job duties to be present in the area. More specifically, access is restricted to those authorized entry by the employer, this final standard, or the OSH Act. By limiting access to these areas to authorized persons only, the additional obligation imposed by the final standard when PPE is used will be limited to as few persons as possible, thus reducing the economic implications of compliance with this standard.

The reasons that regulated areas are to be established in all work areas where the PEL is exceeded, including maintenance operations, is that the existence of a hazard, rather than the type of operation or work being performed, should be the basis for establishment of a regulated area. Areas where exposures are temporarily over the PELs while maintenance is being performed need to be demarcated to warn employees not performing the repairs, and access needs to be temporarily restricted. Further, employees who enter the area are thereby warned to wear the appropriate protective equipment when entering.

There were several other concerns expressed during the hearings regarding how to regulate and deregulate an area. The performance language which is used in the requirement to establish a regulated area allows the employer to establish a regulated area based on the handling, application, or use of non-airborne MDA and to deregulate this area when these activities stop.

Some of the commenters expressed concern with triggering the establishment of regulated area based on the handling, application, or use of non-airborne MDA. More specifically, they argue that the requirement as written would force even the use of small quantities of MDA to be done in regulated areas. The Department of the Air Force (Ex.11-19) states that:

...consideration must be given to operational uses of small quantities of MDA containing materials versus large scale manufacturing processes. This specifically applies to regulated areas for repair processes. We anticipate the use of small MDA-containing patches for repairing aircraft structures. By the definition of regulated area, a certain area of the hangar or repair dock would become a regulated area during the application of a small (2-6 square inch) pre-preg patch. Recommend (sic) a use quantity be established below which either a regulated area is not required or less stringent regulated area requirements are specified.

During the hearings, OSHA questioned the representatives from the Air Force extensively concerning the requirement to establish a regulated area. OSHA clearly stated during the presentation made by the Air Force that it was not the Agency's intent to require that an entire facility become a regulated area just to patch on a 2 inch square on one airplane's wing. The regulated area should be confined to prevent access by unauthorized workers and should establish limits for workers engaged in work activities within these areas. In this instance, this could easily be accomplished without making the entire plant a regulated area.

In fact, OSHA questioned Col. Bishop from the Air Force on precisely this example. After Col. Bishop had agreed that establishing a regulated area in the situation described above was feasible and not difficult, the OSHA attorney summarized Col. Bishop's actual concerns as follows:

I mean you're not suggesting that a compliance officer would come in after reading this language just like you've just read it and assume because your two workers are putting this patch on an airplane wing--there's one on the wing and there's one down handling materials--that that entire hanger will be considered a regulated area because of the dermal exposure situation... (Tr. II, 48)

Colonel Bishop responded: "We have our fears." (Tr. II, 48 ).

OSHA believes that the concerns expressed by Col. Bishop and other hearing participants regarding the difficulties in establishing regulated areas when small amounts of MDA are being used or small repair projects are being done are unfounded. The rationale provided in this preamble for establishing regulated areas will serve as guidance in determining if compliance with these provisions have been achieved. Clearly, in instances when small operations are taking place, it is not the agency's intent to require entire facilities to become regulated areas.

Paragraph (g). Methods of Compliance.

The standard requires that feasible engineering and work practice controls be used to reduce employee exposures to or below the permissible limits. In situations where engineering controls that can be instituted will not reduce exposures to the permissible exposure limits, these controls must nonetheless be used to reduce exposures to the lowest feasible level and be supplemented by the use of respirators. In addition, a compliance program to reduce exposures to within the permissible exposure limits solely by means of engineering and work practice controls must be developed and implemented. Written plans for this program must be developed and furnished upon request for examination and copying to representatives of the Assistant Secretary, representatives of the Director, and affected employees. These plans must be reviewed and updated annually to reflect the current status of the program.

OSHA believes that there are certain activities, often involving certain maintenance and repair operations, as well as in emergency situations, in which the use of engineering controls to control exposures will not be feasible, regardless of the permissible exposure limits in the standard. Where the employer can show that engineering controls for such operations are not feasible, respirators shall be permitted as a means of control.

It has been OSHA policy to require that employers use feasible engineering and work practice controls to prevent excessive employee exposures and that respirators be used as an alternative only when other methods are not adequate, are not feasible, or have not yet been installed. The compliance hierarchy proposed by OSHA was not challenged and as such appears as proposed in the final standard. Nonetheless, it should be noted that OSHA is conducting a separate generic rulemaking on methods of compliance (OSHA Docket No. H-160; 54 FR 23991 (June 5, 1989)). The outcome of that rulemaking may have some future effect on this paragraph.

Paragraph (h). Respiratory Protection

OSHA requires that where respirators are necessary to limit employee exposures to below the permissible exposure limits, the employer must provide the respirators at no cost to the employee, and require that the employees use them.

A table of respirators for use with MDA is included in the standard provisions. The table is similar to those used in other standards and reflects current OSHA policy and is generally used in standard development.

Respirator use is required during the time necessary to install or implement feasible engineering and work practice controls. Further, respirators must be used in: 1) operations in which engineering and work practice controls are not feasible (e.g., certain maintenance operations); 2) work operations for which the feasible engineering and work practice controls are not sufficient to reduce exposures to or below the PEL; and 3) emergency situations.

The final standard also requires that each employee be properly trained to wear a respirator, to know why the respirator is needed, and to understand the limitations of the respirator. An understanding of the hazard involved is necessary to enable the employee to take steps for his or her own protection. The respiratory protection program implemented by the employer must conform to that set forth in 29 CFR 1910.134. This provision contains basic requirements for proper selection, fit, use, cleaning, and maintenance of respirators.

The final standard also contains provisions for emergency respirator use. OSHA believes that emergencies are situations where respirators must be used to protect employees. Since it is unrealistic to predict the expected contaminant concentrations to which an employee may be exposed in all emergencies, OSHA requires the use of respirators of the type approved for protection against unknown concentrations. If an employee is working in an area and using an approved respirator of the type appropriate for the existing concentration, and an emergency occurs, the employee of course should continue using the respirator during his escape. Provisions to provide proper protection for emergency personnel assigned to enter vessels or workplaces containing an unknown concentration to rescue workers or to control the release of the contaminant or perform any necessary repairs will be required to be a part of the emergency plan. This paragraph requires that respirators be made available to employees in these operations.

The final standard also requires the use of qualitative or quantitative fit tests. When negative pressure respirators are used, proper fit is especially critical to prevent leakage of contaminated air into the facepiece.

The employer must ensure that the employees' respirators fit properly and that leakage is minimal. A rapid qualitative fit test can be performed as either a positive-pressure test, in which the exhalation valve is closed and the wearer exhales into the facepiece to produce a positive pressure, or a negative pressure test, in which the inhalation valve is closed and the wearer inhales so that the facepiece collapses slightly. Employees could be trained to perform this test.

The final standard also requires that the employer use the fit testing appendix (Appendix E) to ensure that the employer conducts the proper testing to achieve adequacy of fit testing.

Paragraph (i). Protective work clothing and equipment

The employer is required to provide and the employee to wear the appropriate protective clothing to prevent eye and dermal exposure to MDA. The requirements for the use of personal protective clothing and equipment are consistent with those found in 1910.132 and 1910.133. The equipment is to be provided at no cost to the employee, and includes the use of those items that may be necessary to protect employees at each particular work situation from exposure to MDA, including, where appropriate, such items as face shields, gloves, aprons, coveralls, or footwear.

Contact with liquid MDA irritates the eyes and may result in corneal burns if the MDA is splashed in the eyes. When there is a reasonable possibility of splashing the eyes, precautions are needed. Eye and face protection is currently required by 29 CFR 1910.133, and the types of safety goggles and face shields required by this section to prevent eye and face injury are readily available from safety products companies nationwide.

OSHA's standard is performance-oriented and requires the employer to survey the work situation in determining the type of protective equipment needed. For example, when handling solid materials the employee may be required to wear full body coveralls and gloves, which must be removed at the end of the shift and laundered before being worn again. This employee would also be required to shower at the end of the work shift. Employees required to work only with non-airborne forms of MDA which can result in "dermal exposure to MDA," may not be required to wear full body coveralls but instead may be required to wear an apron, and gloves. If the employee does become splashed with MDA or other substances containing MDA, the employee must be directed to immediately remove the clothing, wash the affected area, and put on clean clothing if necessary. The employer may require employees to discard gloves when removed and use a new pair of gloves after breaks, lunch, etc. The employee's gloves must be sufficiently protective or changed often enough so that MDA-wetted material is not kept in contact with the skin.

The performance approach grants an employer flexibility to achieve the goal of minimizing MDA contact with the skin in a manner the employer finds most effective. However, being performance oriented, it is of necessity more general and requires the employer to consider the work process in order to achieve the desired goal in the manner that the employer believes is most efficient. This provision is designed to prevent the employee from coming in contact with MDA or MDA contaminated substances that may result in "dermal exposure to MDA."

The employer must be aware that maintaining the effectiveness of the protective equipment and clothing used is also of great importance. Exposure occurs by (1) bulk penetration through pinholes, rips, zippers, seams, etc.; (2) material failure through chemical degradation; or (3) permeation through the material.

While not specifically required, OSHA believes that the employer can use permeation data to determine the effectiveness of protective clothing.

Permeation depends on MDA concentration, type of protective material, thickness of protective material, temperature, and age of protective clothing. Liquid MDA that may be spilled on aprons, coveralls, or footwear or protective clothing other than gloves can be wiped off within a few minutes time. Therefore, the materials used to make these types of protective clothes need to be impervious to MDA only for a few minutes. However, the liquid MDA permeability rate for materials used to make gloves needs to be less than that for other protective equipment since it is less likely that gloves will be wiped off when liquid contact occurs. Breakthrough times of MDA through various protective clothing materials differ widely, and the choice of material for protection against MDA breakthrough depends on the type of operation involved and length of time of contact, other solvents present, and other factors. Because of the uncertainty associated with requiring this sort of testing, OSHA chose to adopt regulations which give the employer the option of choosing the methodology relied upon to assure that the effectiveness of protective clothing is achieved. Nonetheless, although there have been limited tests of protective clothing and devices conducted for various toxic materials, OSHA recognizes that all clothing and equipment are not equally protective; and in some cases may actually provide no effective protection. Data analysis indicated that polyvinyl chloride (PVC), natural latex, and polyethylene are currently the best candidates for protection against solutions containing MDA.

Under this provision, employers are obligated to take the appropriate measures to ensure that workers are not dermally exposed to MDA, and to choose the protective clothing or equipment which will achieve this goal. How much clothing and the type of protective clothing needed will depend on the potential for exposure and the conditions of use. The employer in exercising his reasonable judgment in the workplace should be able to select the appropriate clothing or equipment in accordance with the criteria of this paragraph which satisfies the legal obligation defined by this paragraph.

The employer can also use any appropriate method available to determine that the personal protective equipment is functioning properly. For example, the employer may rely on staining of the skin, MDA in the urine, or may conduct dermal monitoring under the protective clothing to determine potential for absorption and consequently the ineffectiveness of personal protective equipment. In addition, the medical surveillance provisions required by OSHA would detect workers who were adversely affected as a result of occupational exposure to MDA.

OSHA also allows the worker to remove some protective clothing outside of the change room. The regulatory text regarding removal of MDA-contaminated protective work clothing and equipment has been slightly modified, both to clarify the provision and to better reflect the Committee's intent (52 FR 26862). These changes also respond to comments that led to Issue #15 in the Notice of Hearing (55 FR 2104). Workers can remove some items like gloves and aprons and discard disposable contaminated protective clothing before leaving a regulated area. Of course, the employer who allows the employee to dispose of contaminated clothing in areas outside of the change rooms is still obligated to comply with the requirements for the proper disposal of MDA contaminated materials. In addition, OSHA requires that clothing not routinely removed throughout the day must be removed at the end of the shift in change rooms.

Paragraph (j). Hygiene facilities and practices

The final standard contains a variety of provisions for the use of shower and change room facilities and lunch rooms for employees exposed to MDA.

For example, whenever food or beverages are consumed at the worksite and employees are exposed to MDA at or above the PEL or are subject to "dermal exposure to MDA" the employer shall provide readily accessible lunch areas. Lunch facilities located in areas where MDA exposures are at or above the PEL must be equipped with a positive pressure filtered air supply. In addition, lunch facilities may not be located in areas where "dermal exposure to MDA" can occur.

Showers are required to be provided for workers exposed to dusts or vapors in concentrations in excess of the action level. Workers subjected only to "dermal exposure to MDA" must be instructed to immediately wash exposed areas with soap and water or any media which does not increase the absorption properties of MDA. This particular requirement was given much consideration by OSHA.

OSHA is concerned with the appropriate manner in which MDA should be removed from the skin. However, OSHA did not want to require that only soap and water be used to remove MDA impregnated resin or accumulations on the skin because something better might be developed in the future. In fact, OSHA believes that it is better, should exposure occur, to remove the hardened resin or other MDA material as soon as possible even if a solvent must be used. OSHA believes that if the employer can demonstrate that a particular solvent does not increase the absorption properties of MDA it should be used to remove MDA from the skin. The final standard also requires that the employer ensure that all employees who have been exposed to MDA at or above the PEL wash their hands and face with soap and water prior to eating, drinking, smoking or applying cosmetics, and taking breaks. This requirement is intended to prevent the accidental ingestion of MDA.

Paragraph (k). Communication of hazards to employees

Signs and Labels.

The final standard requires that the employer post and maintain legible signs demarcating regulated areas and entrances or access ways to regulated areas with the following legend:

                        MAY CAUSE CANCER
                           LIVER TOXIN

These signs are intended to supplement the training which employees are required to receive under the standard. Even trained employees will need to be reminded of the locations of regulated areas and the dangers of entering these areas. In addition, other personnel, such as employees of independent maintenance contractors authorized to enter regulated areas, need to be informed of the locations of regulated areas, the dangers of entering these areas, and the need to use protective equipment. OSHA has determined that both signs and training are necessary to apprise employees adequately of the hazards associated with MDA exposure.

OSHA also requires specific wording of the warning signs for regulated areas to assure that the proper warning is given to employees. The word "danger" is used to attract the attention of workers, alert them to the fact that they are in a hazardous area and to emphasize the importance of the message that follows. In addition, the use of the word "danger" is consistent with recent OSHA health standards dealing with carcinogens. The sign legend: "Respirators and Protective Clothing May Be Required to Be Worn In This Area," recognizes that there may be a difference between the MDA concentrations in air or the potential to be splashed with liquid mixtures, (the bases which determine when a regulated area must be established), and a particular employee's likely exposure.

The standard also requires labeling of containers of MDA. The labels must state, for (a) MDA:

                          CONTAINS MDA
                        MAY CAUSE CANCER
                           LIVER TOXIN

and for (b) Mixtures containing MDA:

                          CONTAINS MDA
                           LIVER TOXIN

The final standard is consistent with section 6(b)(7) of the Act, which prescribes the use of labels or other appropriate forms of warning to apprise employees of the hazards to which they are exposed.

It is required that labels remain affixed to containers leaving the workplace. The purpose of this requirement is to assure that all affected employees, not only those of a particular employer, are apprised of the hazardous nature of MDA exposure.

It is OSHA's view that informing employees of the hazards to which they are exposed is an important element in reducing occupational disease and injury and one of the significant purposes of the Act. Section 6(b)(7) of the Act does not limit an employer's obligation to inform employees of hazardous conditions, to the employer's own employees. When an employer manufactures, formulates, or sells a product, the employer may create exposures not only to his or her own employees, but also to the employees of other employers involved in handling, transporting, or using the product.

Material Safety Data Sheet (MSDS)

The final standard also requires statements to be incorporated into a material safety data sheet. Information to assist in the preparation of a MSDS can be found in Appendices A and B.

Employee information and training

OSHA requires that all employers provide a training program for all employees exposed to MDA, initially at the time of assignment and at least annually thereafter. OSHA also requires an information and training program to inform employees of the hazards to which they are exposed and to provide employees with the necessary understanding of the degree to which each employee can contribute toward minimizing health hazard potentials.

The content of the training program is intended to inform employees of:

(1) the hazards to which they are exposed; (2) the necessary steps to protect themselves, including those to be taken during emergency situations; (3) limitations and the proper use of respirators and protective equipment; (4) a description of medical examinations and their purpose; (5) implementation of work practices and the use of available engineering controls; and (6) the contents of this standard. Section 6(b)(7) of the Act makes it clear that these are appropriate goals for an employee training program, and the final standard includes such provisions.

OSHA requires the employer to make a copy of the standard and its appendices available to affected employees and their representatives. This requirement, in combination with the review provided for as part of the training program, is intended to ensure that employees understand their rights and duties under this standard.

The employer is also required to provide, upon request, all materials relating to the training program to affected employees, the Assistant Secretary and the Director. This is intended to provide an objective check of compliance with the requirements under this paragraph. The regulatory text reflecting these access provisions, found in the final standard in paragraph (k)(4), were inadvertently omitted in both the Committee document and the proposal. The preamble discussion in both documents, however, was complete. Also, the regulatory text was included in the construction standard. Since the construction text and the preamble discussions generated no comment and since these requirements are entirely consistent with other OSHA single substance standards, the access provisions are included in the final standard.

OSHA recognizes that MDA may be only one of a number of substances to which an employee may be exposed simultaneously in the workplace. The education and training requirements in this standard contain those elements OSHA has determined to be basic. The format and content of the required training and information program are neither rigid nor extensive.

Paragraph (l). Housekeeping

The final standard requires that employers institute a program to detect leaks, spills and discharges of MDA which includes visual inspections. When leaks, spills, or discharges of MDA are detected, the final language requires the employer to repair promptly all leaks and clean up all spills. These work practices aid in minimizing the number of employees exposed, as well as the extent of any potential for MDA exposure.

Prevention and removal of accumulations of liquid MDA on all surfaces are critically important aspects of minimizing employee exposure. The liquid, if allowed to remain on the floor or work surfaces, will slowly evaporate and contribute to a possible airborne hazard, or it may become a dermal hazard through inadvertent skin contact. MDA's low vapor pressure which results in slow evaporation will contribute to and prolong the hazard. The requirement to clean up spills and drips refers to the prevention and removal of visible accumulations of liquid MDA on all surfaces.

In addition to the hazards of exposure to MDA in its liquid forms, hazards also result from exposure to the dusts of MDA. Thus, the final language contains provisions for maintaining surfaces as free as possible of accumulations of dusts and waste containing MDA. Surfaces contaminated with dusts may not be cleaned by the use of compressed air. The final standard requires HEPA-filtered vacuuming equipment for vacuuming. This equipment must be emptied in a manner which minimizes the reentry of MDA dusts into the workplace.

Paragraph (m). Medical Surveillance

The final standard requires that each employer institute a medical surveillance program for all employees exposed to MDA under the following circumstances:

(1) Employees exposed at or above the action level to dusts or vapors for 30 or more days per year;

(2) Employees who are subject to "dermal exposure to MDA" for 15 or more days per year;

(3) Employees who have been exposed in an emergency situation;

(4) Employees whom the employer, based on results from compliance with paragraph (e)(8), has reason to believe are being dermally exposed; and

(5) Employees who show signs or symptoms of MDA exposure.

The standard requires that the medical surveillance program provide each covered employee with an opportunity for a medical examination. Further, all examinations and procedures must be performed by or under the supervision of a licensed physician and be provided without cost to the employee. Clearly, a licensed physician is the appropriate person to supervise and evaluate medical examinations. However, certain parts of the required examination do not necessarily require the physician's expertise and may be conducted by another person under the supervision of the physician.

The standard also requires that examinations be given at a reasonable time and place. It is necessary that examinations be convenient and be provided without loss of pay to the employee to assure that they are taken.

The final standard allows the examining physician to prescribe the specific tests to be included in the medical surveillance program. While unable to make findings regarding the use of bladder cancer testing in the NPRM and therefore not requiring such tests in the regulatory text, OSHA asked for public comment concerning the appropriateness of such a requirement (54 FR 20704). No comments were received in response and OSHA is not including such a requirement in the final rule. Nonetheless some specific requirements are included, such as:

(i) comprehensive medical and work histories with special emphasis directed to an evaluation of other carcinogens to which the employee is exposed, and smoking and alcohol use.

(ii) comprehensive physical examination, with particular emphasis given to symptoms related to skin disease and liver dysfunction.

(iii) urinalysis. (iv) screening for liver damage. It is important to note that the employer is required to make any prescribed tests available more often than specified if recommended by the examining physician.

OSHA also requires that the employer provide examinations advised by the physician to any employee exposed to MDA under emergency conditions. Due to the effects of high short-term exposures, it appears prudent to monitor such affected employees in light of existing health data. However, trivial exposure, for example, to a single drop of an MDA-containing mixture would not trigger the emergency examination requirement, particularly if the employee were able to remove the MDA immediately after exposure.

The employer is also required to provide the physician with the following information: a copy of this standard and its appendices; a description of the affected employee's duties as they relate to the employee exposure level; and information from the employee's previous medical examinations which is not readily available to the examining physician. Making this information available to the physician will aid in the evaluation of the employee's health in relation to assigned duties and fitness to wear personal protective equipment.

The employer is required to obtain a written opinion from the examining physician that contains the results of the medical examination; the physician's opinion as to whether the employee has any detected medical conditions which would place the employee at increased risk of material health impairment from exposure to MDA; any recommended restrictions upon the employee's exposure to MDA or upon the use of protective clothing or equipment such as respirators; and a statement that the employee has been informed by the physician of the results of the medical examination and of any medical conditions which require further explanation or treatment. This written opinion must not reveal specific findings or diagnoses unrelated to occupational exposure to MDA, and a copy of the opinion must be provided to the affected employee.

The requirement that a physician's opinion be in written form will ensure that employers have had the benefit of this information. The requirement that an employee be provided with a copy of the physician's written opinion will ensure that the employee is informed of the results of the medical examination. The purpose in requiring that specific findings or diagnoses unrelated to occupational exposure to MDA not be included in the written opinion is to encourage employees to take the medical examination by removing the concern that the employer will obtain information about their physical condition that has no relation to present occupational exposures.

The standard also includes a multiple physician review mechanism in paragraph (m)(6). In recommending this provision, the Committee relied heavily on the experiences of its members regarding a similar provision under the OSHA lead standard. OSHA accepted this recommendation in the NRPM. Since the provision generated no comment or controversy, other than a limited request for clarification, the provision is substantively promulgated as proposed (52 FR 26865).

This provision is triggered where an employee disagrees with the opinion of a physician, selected by the employer, whose examination disclosed signs or symptoms of occupational exposure to MDA, when the opinion could affect the employee's job status.

In paragraph (m)(9), the standard also contains provisions for removing an employee from exposure in certain circumstances, following a medical examination. In recommending this provision, again the Committee relied heavily on the experiences of its members regarding a similar provision under the OSHA lead standard. OSHA accepted this recommendation in the NRPM. In addition, the regulatory text regarding removal of employees from exposure at or above the action level for MDA or where dermal exposure to MDA may occur has been slightly modified, both to clarify the provision and to better reflect the Committee's intent (52 FR 26865). Since the provision generated no comment or controversy the provision is substantively promulgated as proposed. OSHA believes that employees whose health has been adversely affected as a direct result of occupational exposure to MDA should be removed from exposure and should receive medical removal benefit protections.

Paragraph (n). Recordkeeping

The standard's requirements are consistent with Section 8(c)(3) of the Act which provides for the promulgation of regulations requiring employers to maintain accurate records of employee exposures to potentially toxic or harmful physical agents which are required to be monitored or measured.

The final standard allows that objective data be used for any exemptions from the standard. Records of objective data must be maintained to demonstrate that employees will not be exposed to airborne MDA concentrations and that no "dermal exposure to MDA" can occur.

The standard also requires that records be kept to identify the employee monitored and to reflect the employee's exposure accurately. Specifically, records must include the following information: (a) the names and social security numbers of the employees sampled; (b) the number, duration, and results of each of the samples taken, including a description of the representative sampling procedure and equipment used to determine employee exposure where applicable; (c) a description of the operation involving exposure to MDA which is being monitored and the date on which monitoring is performed; (d) the type of respiratory protective devices, if any, worn by the employee; and (e) a description of the sampling and analytical methods used, and evidence of their accuracy.

The final standard also includes a provision for requiring the employer to keep an accurate medical record for each employee subject to medical surveillance. Section 8(c) of the Act authorizes the promulgation of regulations requiring any employer to keep such records regarding the employer's activities relating to the Act as are necessary or appropriate for the enforcement of the Act or for developing information regarding the causes and prevention of occupational illnesses. OSHA believes that medical records, like exposure monitoring records, are necessary and appropriate to both the enforcement of the standard and the development of information regarding the causes and prevention of illness.

The employer is also required to keep a record of any employee's medical removal and return to work status.

The standard requires that all records required to be kept shall be made available upon request to the Assistant Secretary and the Director of NIOSH for examination and copying. Access to these records is necessary for the agencies to monitor compliance with the standard. These records may also contain information needed by the agencies to carry out their other statutory responsibilities.

The standard would also provide for employees, former employees, and their designated representative to have access to mandated records upon request. Section 8(c)(3) of the Act explicitly provides "employees or their representatives" with an opportunity to observe exposure monitoring and to have access to the records of monitoring procedures and results; several other provisions of the Act contemplate that employees and their representatives are entitled to play an active role in the enforcement of the Act.

Access to exposure and medical records by employees, designated representatives, and OSHA shall be established in accordance with 29 CFR 1910.20. By its terms, it applies to records required by specific standards, such as this MDA standard, as well as records which are voluntarily created by employers. In general, it provides for unrestricted employee and designated representative access to exposure records. Access to medical records is also provided to employees and, if the employee has given specific written consent, to the employee's designated representatives. The standard requires that unrestricted access to both kinds of records be allowed, but access to personally identifiable records is made subject to rules of agency practice and procedure concerning OSHA access to employee medical records, which have been published at 29 CFR 1913.10. An extensive discussion of the provisions and rationale for 1920.20 may be found at 45 FR 35312; the discussion of 1913.10 may be found at 45 FR 35384.

It is necessary to keep records for extended periods because of the long latency periods commonly observed for carcinogens. Cancer often cannot be detected until 20 or more years after onset of exposure. The extended retention period is therefore needed for two purposes. Diagnosis of disease in employees is assisted by having present and past exposure data as well as the results of the medical exams. Retaining records for extended periods also makes it possible at some future date to review the adequacy of the standard.

The time periods recommended for retention of exposure records and medical records are thirty years, and period of employment plus thirty years, respectively. These retention periods are consistent with those found in other OSHA health standards.

The standard would also require certain employers to notify the Director in writing at least 3 months prior to the disposal of the records. Section 1910.20(h) also contains requirements regarding the transfer of records.

Paragraph (o). Observation of Monitoring

The standard also includes a provision for observation of exposure monitoring. This provision 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. Any observer must be provided with the personal protective clothing and equipment that is required to be worn by the employees who are working in the area. The employer is required to assure the use of such clothing and equipment or respirators and is responsible for requiring that the observer complies with all other applicable safety and health procedures.

Paragraph (p). Effective dates

The standard becomes effective thirty (30) days from the publication of the final standard September 9, 1992. The effective date established in the final standard remains the same as the date which appeared in the proposed rule.

Paragraph (q). Appendices

Five appendices have been included at the end of this final standard. Appendices A,B, C, and D have been included primarily for purposes of information. None of the statements contained in Appendices A,B,C, and D should be construed as establishing a mandatory requirement not otherwise imposed by the standard, or as detracting from an obligation which the standard does impose. However, the protocols for respiratory fit testing in Appendix E are mandatory.

Appendix A contains information on the description and exposure levels of MDA. Also provided in Appendix A is information on the health hazards associated with exposure, descriptions of protective clothing and equipment, emergency and first aid procedures, medical requirements, provisions for the observation of monitoring, access to exposure and medical records, and precautions for the safe use, handling, and storage of MDA.

Appendix B contains "substance technical guidelines" for MDA, including physical and chemical data, spill and leak procedures, including waste disposal methods, and other miscellaneous precautions for the safe handling of MDA.

Appendix C contains the medical surveillance guidelines for MDA. Included in these guidelines are the description of the routes of entry, the toxicology and symptoms and signs associated with MDA exposure, information on the treatment of acute toxic effects, and surveillance and preventive considerations, including hematology guidelines which may be useful to physicians in conducting the medical surveillance program required by paragraph (m) of this final standard.

Appendix D gives details of the sampling and analytical methods for use in monitoring employee exposures to MDA.

Appendix E gives detailed fit testing procedures that are to be followed for qualitative or quantitative fit testing of negative pressure respirators. Various protocols for qualitative and quantitative fit tests are outlined in detail.

All the Appendices are designed to aid the employer in complying with the requirements of the standard. Paragraph (k) of this final standard on the "communication of MDA hazards to employees" specifically requires that the contents of the standard and Appendices A and B be made available to affected employees. Information contained in Appendix C on medical surveillance is to be explained to affected employees. Appendix C also provides information needed by the physician to evaluate the results of the medical examination.

Paragraph (r). Start-up dates.

The final standard contains start up dates for the various standard provisions. The dates originally proposed in the MDA rule have been modified to reflect a more logical schedule for compliance. These dates are based on economic and technological considerations discussed in the regulatory impact analysis.

[57 FR 35630, Aug. 10, 1992]

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