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Regulations (Preambles to Final Rules) - Table of Contents
• Record Type: Air Contaminants
• Section: 4
• Title: Section 4 - IV. Overview of Rulemaking

IV. Overview of Rulemaking

A. History of Health Standards and Need to Revise PELs

One of the principal reasons, if not the single most important basis, for Congress passing the Occupational Safety and Health Act of 1970 was Congress' recognition of the need to protect workers from occupational health hazards. In the preamble to the Act, Congress stated that one of the purposes was to protect employees by "exploring ways to discover latent diseases, establishing causal connections between diseases and work in environmental conditions, and conduct other research relating to health problems, in recognition of the fact that occupational health standards present problems often different from those involved in occupational safety." (emphasis added).

The legislative history indicates Congressional concern for reduction in health risk from both the recognized hazards and from the many newly utilized chemicals. Congress stated in 1970:

In the field of occupational health the view is particularly bleak, and due to the lack of information and records, may well be considerably worse than we currently know. Occupational diseases which first commanded attention at the beginning of the Industrial Revolution are still undermining the health of workers. Substantial numbers, even today, fall victim to ancient industrial poisons such as lead and mercury. Workers in the dusty trades still contract various respiratory diseases. Other materials in industrial use are only now being discovered to have toxic effects. In addition, technological advances and new processes in American industry have brought numerous new hazards to the workplace. Carcinogenic chemicals, lasers, ultrasonic energy, beryllium metal, epoxy resins, pesticides, among others, all present incipient threats to the health of workers. Indeed, new materials and processes are being introduced into industry at a much faster rate than the present meager resources of occupational health can keep up with. It is estimated that every 20 minutes a new and potentially toxic chemical is introduced into industry. New processes and new resources of energy present occupational health problems of unprecedented complexity. (Senate Report 91-1282, p.2).

To accomplish the goal of protecting workers from occupationally related disease Congress created a three-pronged approach in the OSH Act.

First, Congress desired that OSHA, as soon as possible after it was established, have in existence a set of basic, minimum health and safety standards. To accomplish this it provided in Section 6(a) of the OSH Act that OSHA should adopt within its first two years, without hearing or public comment, established federal standards and national consensus standards.

At that time, under the Walsh-Healy Act, the Department of Labor had adopted for government contractors approximately 400 health standards based on the Threshold Limit Value (TLV) recommendations of the American Conference of Governmental Industrial Hygienists (ACGIH). Those were adopted as established federal standards. In addition about 25 exposure limits had been recommended by the American Standards Association (presently called the American National Standards Institute). Those were adopted as national consensus standards. OSHA adopted these initial exposure limits in May, 1971. They are for the most part the maximum air contaminant levels set forth in Tables Z-1, Z-2, and Z-3 of 29 CFR 1910.1000.

Congress recognized the need to update and add new standards. It created two mechanisms for this purpose: regular or "6(b)" standards and emergency or "6(c)" standards.

Congress specified the procedures for developing and promulgating regular standards in Sections 6(b)(1)-(4) and 6(f). These sections provide that: the public may petition for new standards; OSHA may set up an advisory committee to assist in developing a standard; and, before issuing a standard, OSHA must publish a proposal with an explanatory preamble, request public comments and then publish an explanatory preamble with a final standard. In addition to these general requirements of informal rulemaking, Congress specified that OSHA must hold an oral hearing if requested and support its determination with substantial evidence in the rulemaking record.

Congress also provided in Section 6(c) for the issuance of Emergency Temporary Standards (ETS) to take immediate effect without rulemaking. However, OSHA must then complete a Section 6(b) rulemaking within 6 months. The criteria for issuing an ETS is that "employees are exposed to grave danger from exposure to substances or agents determined to be toxic or physically harmful or from new hazards, and that such emergency standard is necessary to protect employees from that danger." OSHA has found that Sec. 6(c) procedures have not generally accelerated the regulatory process. Most ETS's have been litigated and judicial stays have been issued either on procedural or substantive grounds.

Since the passage of the Act in 1970, OSHA has made substantial progress in improving the occupational health of workers for some priority health hazards. Asbestos and arsenic exposures have been dramatically reduced, substantially reducing cancer risk to employees. Lead exposures have been reduced and we are now seeing a major reduction in employee blood lead levels, and lead related diseases. Cotton dust exposures have been reduced and byssinosis has been nearly eliminated from the textile work force. OSHA has also substantially reduced significant health risk from some of the newer chemicals such as ethylene oxide and vinyl chloride.

Through the hazard communication and access to employee exposure and medical records standards, OSHA has greatly expanded the ability of employees to learn about and protect themselves from health hazards.

OSHA's standards have proven to be feasible, often costing less than estimated. The vinyl chloride standard cost one-tenth OSHA's contractor's estimate. The cotton dust standard has been credited with improving the industry's competitiveness and productivity by stimulating major technology improvements while costing one-half OSHA's estimate.

The preambles to OSHA standards have been lengthy, detailed and sophisticated. They have thoroughly analyzed health studies and controversial scientific issues about carcinogenicity and risk assessment. Extensive analyses of feasibility have been made.

OSHA has issued only 24 substance-specific health regulations since its creation. It has not been able to review the many thousands of currently unregulated chemicals in the workplace or to keep up with reviewing the several thousand new chemicals introduced since its creation.

Using past approaches and practices, OSHA could continue to regulate a small number of the high priority substances and those of greatest public interest. However, it would take decades to review currently used chemicals and OSHA would never be able to keep up with the many chemicals which will be introduced in the future.

OSHA believes it is a major priority to update its existing PELs and to make a substantial effort to control exposure to chemicals newly used in the workplace for which no exposure limits exist. The existing health literature and expert judgment indicate that such new or lower limits are needed to protect against many types of deleterious health effects. These include kidney and liver diseases, respiratory diseases, reductions in lung function, nerve disorders and reduction in nerve function, carcinogenicity, irritation to the eyes, throat, skin and other organs which prevent working safely, and many other disorders and dysfunctions.

As the final regulatory analysis indicates, millions of employees are exposed to levels of these chemicals which, the literature or expert opinion indicates, do or may create deleterious health effects. Clearly, it is a most important occupational health priority to reduce or eliminate such disease and material impairments of health.

Congress clearly indicated that it was a major Congressional priority to consider and control, when needed, the many thousands of unregulated chemicals, and update the existing Z-Table chemicals. For example, the previous quotation indicated Congress' concern with the thousands of newly introduced chemicals. Congress also stated:

Accordingly, it is essential that such standards (Table Z chemicals) be constantly improved and replaced as new knowledge and techniques are developed. In addition there are occupational hazards, particularly those affecting health - which are not covered by any standards at all. (Senate Report 91-1282, p.6).

Government agencies and professional organizations have also recommended that OSHA lower exposures for many Z-Table substances and add limits for currently unregulated substances. The National Institute for Occupational Safety and Health has recommended new or lower exposure limits for approximately 190 chemicals (RELs) in its Recommendations for Occupational Safety and Health Standards, Sept. 1986.

The American Conference of Governmental Industrial Hygienists (ACGIH) 1987-88 Threshold Limit Values (TLVs) adopted new exposure limits for more than 160 substances not regulated by OSHA, and lower limits, short-term exposure limits, ceiling limits or skin designations for more than 210 substances now regulated by OSHA.

In light of its priority to address the many unregulated health hazards and improve the existing Z-Table limits, OSHA commenced a review process to determine the best way to achieve this goal. It reviewed its past history and set up an internal task force to consider the matter. In addition, OSHA requested the Administrative Conference of the United States to study the issue and make recommendations.

OSHA's analysis indicated a number of reasons why the standards development process takes so long. These are discussed below. As can be seen some are within OSHA's control and some are not.

OSHA, in the past, has determined which substances it would commence standards development activity upon either through response to petitions or internal reviews. The time and resources spent analyzing what should be done next has been considerable.

An exhaustive review of the literature for each substance has been completed prior to initiating rulemaking. Detailed presentations for each study and lengthy discussions of every conceivable issue have been completed.

The lengthy preamble which has become a regular part of each standard is largely the result of the need for OSHA to defend its standards in suits brought inevitably by both industry and labor. See for example Synthetic Organic Chemical Mfgs. v. Brennan; Oil Chemical and Atomic Workers v. Brennan, 503 F. 2d 1155, 506 F. 2d 385 (3rd. Cir. 1974); Public Citizen, Health Research Group et al v. Tyson; Association of Ethylene Oxide Users v. Tyson, 796 F. 2d 1479 (D.C. Cir. 1986). OSHA feels more confident in the successful defense of a standard if all possible issues have been exhaustively explored.

Individual standards have included a full range of ancillary provisions such as monitoring, medical surveillance, action levels and work practices. This increases the issues that must be studied and discussed, adding to the time taken to complete a standard.

OSHA has performed technical and economic feasibility analyses as required by statute. These have been made lengthier and more time consuming because a range of possible alternative exposure limits have been explored.

The regulatory process is also longer and more resource intensive because of analyses required either by statute or executive order. OSHA develops Environmental Impact Statements as required by the National Environmental Policy Act, conducts Regulatory Flexibility Analyses as required by the Regulatory Flexibility Act and conducts detailed analyses required by the Paperwork Reduction Act. All of the Presidents who have been in office during OSHA's existence have stressed the need to reduce inflation and improve the cost effectiveness of regulations. Under various Executive Orders (E.O. 12044, 12291, etc.) OSHA has been required to perform extensive economic analyses.

OSHA has also followed more extensive and elaborate administrative procedures than other health regulatory agencies. In addition to extensive preambles to the proposed and final regulations, there is usually advance notice of a proposal in the Federal Register. There is a complete rulemaking docket into which the Agency places all the studies it relied upon. In addition to public comment and an oral hearing as required by law, opportunity is given for post hearing evidence and briefs. During the hearing, questioning of witnesses, OSHA and its contractors is permitted.

Consequently OSHA has permitted the public more extensive procedural opportunities than its statute, the Administrative Procedures Act, or legal doctrine require. See the procedural rules in 29 CFR Part 1911. and International Harvester v. Rucklehaus, 478 F. 2d 619 (D.C. Cir. 1973). These procedures can increase agency knowledge and have been commended by the courts. (See Industrial Union Dept. v. Hodgson 499 F. 2d 467 (D.C. Cir 1974). However, they do mean that if delays and continuances are granted at each stage, the length of the rulemaking process is substantially extended.

OSHA in its first 17 years has also had to address difficult scientific feasibility and policy issues. These include extrapolation from animal data to humans (ETO supra), epidemiology, risk assessment and significant risk analysis (Arsenic , 48 FR 1864, January 14, 1983; Asbestos, 51 FR 22612, June 20 1986), feasibility for industries with aging facilities (lead, arsenic, supra), lowest feasible level (Benzene, 52 FR 34460, September 11, 1987, for example and others). Naturally when considering such issues for the first time, an Agency desires to go through extensive reviews before reaching final decisions.

OSHA consulted with the Administrative Conference of the United States (ACUS) to determine what would be appropriate procedures to respond to the issue of the large number of chemicals which need new exposure limits. The Conference issued two lengthy reports of a study conducted by two professors of administrative law. After extensive consideration, the ACUS made two sets of recommendations to OSHA. Recommendation 87-1, 52 FR 23629 (1987) and 87-10, 52 FR 40147 (December 30, 1987).
The Administrative Conference specifically recommended:
1. Updating the 1971 Consensus Standards. The Occupational Safety and Health Administration, as an interim step, should continue to update the Table Z national consensus standards adopted in 1971 if updating can be accomplished by expedited rulemaking procedure (e.g., including more concise preambles) appropriate to the nature of the revised Table. OSHA should update the 1971 standards on a generic basis (i.e., include multiple standards in one proceeding) when consensus recommendations are available which are generally accepted by employers and workers in the affected industries, and when the new standards can be evaluated on the basis of risk and feasibility information reasonably available to the Agency. This interim step should not interfere with OSHA's continuing responsibility to promulgate and modify safety and health standards.

As this discussion indicates, there is a clear and generally recognized need to improve occupational health protection of workers from a substantial number of chemicals which are present in the workplace. Clearly an improved approach to regulation is needed to solve this problem in a reasonable time period. OSHA's traditional approach, which has permitted on the average less than two major health regulations per year, is not adequate to address the backlog of at least 400 chemicals generally recognized as needing new or lower exposure limits. OSHA has reviewed the law, Congressional intent, its history, and the recommendations of experts. Based on this review, OSHA adopted the approach described in Section IV-C which it has followed to accomplish the crucial goal of improving occupational health protection of workers. OSHA concluded that this approach has a greater health benefit and will prevent more deaths and various deleterious health effects, than could be achieved by allocating the same resources to comprehensive rulemaking for a small group of substances.

B. Chronology of Regulation

The public process followed by OSHA to implement this rulemaking was started on October 26, 1987, when the Department of Labor published its Semiannual Agenda of Regulations at 52 FR 404494, 40534. The entry titled "Permissible Exposure Limit Update" states OSHA would propose a wide scale updating of its exposure limits. That entry scheduled March 1988 for the proposal and October 1988 for the final regulation. It also indicated that the American Conference of Governmental Industrial Hygienists had updated many of its recommended exposure limits (TLVs) since 1968. The 1968 TLVs were used as the basis of most of OSHA's existing 6(a) exposure limits. A similar notice was published in the next Semiannual Agenda on April 29, 1988, at 53 FR 14024.

OSHA published its proposal, "Air Contaminants, Proposed Rule" on June 7, 1988, at 53 FR 20960 (Ex. 2). That document filled 433 Federal Register Pages. It considered whether exposure limits should be changed for 428 substances. New or lower limits were proposed for 402 substances, one was proposed to be raised and 25 were proposed to be unchanged.

That document included a 21 page discussion of the history, approach and general issues. There followed 250 pages of health discussions which included general discussions by type of effect (cardiovascular, kidney/liver, etc.) and a concise individual discussion of the health effects associated with exposure to each substance. The more important or controversial substances had somewhat longer discussions than other substances. Each individual substance discussion stated the health effects, summarized the major relevant studies, and stated the reason OSHA preliminarily concluded significant risk did or did not exist. Finally, the complete Preliminary Regulatory Impact, Regulatory Flexibility and Feasibility Analysis was printed running 71 pages along with one of the supplements on methodology. (In this instance one Federal Register Page equaled approximately five double-spaced typed pages.) OSHA placed in the public docket either before June 7th, or shortly thereafter, all of the studies or documents upon which it relied. This included Exs. 1-1 to 1-1208, which constitute virtually all of the health studies upon which OSHA relied and that were discussed in the preamble (a few minor or foreign studies referenced by ACGIH were not available). Also included were many data bases on occupational health such as the ACGIH documentation, NIOSH publications (for example NIOSH-TIC, Ex. 7, is a 2500 page summary of health effects organized by chemical) and exposure limits of other countries.

Also placed in the Docket were 6 supplements to the Regulatory Impact and Feasibility Analysis (Exs. 4A-4F, approximately 1500 pages). Four volumes of exposure, control technology and feasibility data organized by chemical were placed in the record as Ex. 6 and a computer data tape for these volumes was made available.

The June 7 Proposal scheduled July 1 for notices of intent to appear at the hearing, July 8 for the submission of comments and testimony, and July 20 for the hearing to begin. It suggested August 12 for post-hearing evidence and August 26 for post-hearing briefs.

OSHA received several requests for extensions of time, some for quite extended periods such as 9 months. On July 1 (53 FR 24956) (Ex. 5) OSHA granted a brief extension. Comments and testimony were due July 25 and the hearing was scheduled to commence July 28. August 19 and September 2 were recommended respectively for post-hearing evidence and briefs.

In response to the proposal, OSHA received 1248 timely comments (Ex. 3-1 to 3-1248) and 204 late comments (Ex. L-3-1249 to L-3-1452). Approximately 800 of the comments and most of the late comments were very similar letters generated by trade associations interested in the regulation of grain dust, wood dust or styrene. The balance of comments ranged from short to 3000 page submissions expressing views on the Proposal and including various studies.

OSHA also received 92 Notices of Intention to Appear (Exs. 8-1 to 8-92). Approximately half of those included copies of testimony and substantive evidence to be presented at the hearing. Established and published procedures require that persons may testify for no longer than 10 minutes at the hearing without submitting a notice.

The public comments, evidence and testimony totaled approximately 25,000 pages. This included actual comments and views, and attached health and feasibility studies.

OSHA submitted to the docket in a timely fashion on July 25, 1988, statements by the Director of Health Standards, the panel of economic witnesses, and 7 other witnesses requested to testify by OSHA. NIOSH also submitted on that date its comments, testimony and views.

In addition, for the convenience of the public, NIOSH placed in the record the paper copy of all health studies on each substance in the rulemaking organized by substance. This included the minor studies as well as the major ones that OSHA had relied on and had already submitted to the record. This submission was lengthy; however, all this information was indexed in the NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) which is a 5 volume bibliography of occupational health studies which NIOSH is required by statute to create and maintain. (Sec. 20(a)(6) of the OSH Act). The RTECS have been available for many years. The vast majority of studies NIOSH placed in the docket were publicly available either in major libraries or from several computer data bases. Consequently they had all been readily available to the public for many years. Participants testified that they could be easily researched (Tr. August 4, Test. of Factor).

As OSHA had expected, a review of the comments and testimony indicates that of 428 chemical in the rulemaking, approximately 280 received no comments or testimony and OSHA preliminary conclusions on risk and feasibility were reasonable and correct. Approximately 100 substances received only limited mention by one or a few participants. Approximately 40 substances received substantive comments but in some of these instances OSHA's proposed PEL was not necessarily controversial. For example, the comments may have been directed at technical improvements. Finally, approximately ten substances received substantial comments and were deemed to be controversial. Because of this filtering process, the rulemaking, as OSHA had anticipated, developed a narrower and more manageable form.

Also, as had been OSHA's prior experience, major industry trade associations were already formed, represented by major law firms, to express views on the more controversial substances. For example, the Styrene Institute, which has been in existence for 12 years, submitted about 2500 pages of comments, studies and attachments (Ex. 3-742) and was represented by Keller & Heckman. The Carbon Disulfide Committee, which has been in existence 11 years, submitted approximately 1000 pages of comments and attachments (Ex. 3-747) and was represented by Gibson, Dunn and Crutcher.

The Trade Unions also made major submissions on the chemicals they were interested in. The Food and Allied Trades Department of the AFL-CIO submitted extensive information on grain dust (Ex. 3-751). The Amalgamated Clothing and Textile Workers Union submitted extensive information on perchloroethylene (Ex. 43). The AFL-CIO (Ex. 39), United Autoworkers (Ex. 42), Workers' Institute of Safety and Health, United Paperworkers, Carpenters and Woodworkers, and other unions also made major submissions.

The oral hearing commenced on July 28. It extended for 13 hearing days with an average of approximately 7 hours of actual hearing time each day. The total transcript was approximately 4000 pages. Approximately 200 witnesses testified and responded to questions. Although there were some limits on questioning by an individual participant, the questioning in total was extensive since there often were more than 10 participants who questioned a particular witness. It was evident that all participants had been able to ask all the questions they wished by the end of the hearings. (Statement of Administrative Law Judge, Tr. pp. 12-15 to 12-17, Aug. 12 1989).

The OSHA Staff panel responded to questions for three-quarters of one hearing day. The OSHA economics panel responded to questions on three separate occasions so that the public could complete questioning and have an opportunity to ask questions after having reviewed all OSHA submissions. The other OSHA witnesses fully responded to questions as did NIOSH (Tr. August 1). NIOSH agreed to return for further questions, but participants who initially requested the right to ask further questions withdrew their requests.

OSHA submitted to the Docket on July 25, 1988, approximately 40 site visit reports and on August 8, 1988, approximately 40 more site visit reports were submitted. The site visits were supplementary to the survey data and were not the basis of OSHA's initial feasibility conclusions. The OSHA economics panel returned on August 15, 1988, to answer questions specifically on those visits.

OSHA's initial goal was to complete 100 site visits. However, the visits needed employer approval both for the visit and the subsequent report before the visit could be undertaken and/or the report submitted to the Docket. Consequently OSHA could not completely control the completion of the site visits or submission of the report to the Docket. OSHA completed several additional site visits, but could not complete the related reports prior to the end of the hearing. OSHA submitted those reports to the employer in order to give the employer the option of putting them in the docket. Employers in the steel industry and styrene users did submit several such reports to the docket. Employers with grain exposures initially refused to permit site visits. Although some later agreed to site visits, it was by then too late to complete the visits and submit the reports to the record, so the site visits were not made.

At the end of the hearing, the presiding officer indicated that, because of the broad scope of the hearing, post-hearing evidence should be due 90 days after the close of the hearing and post-hearing briefs 120 days after the close of the hearing (Ex. 81). OSHA indicated both at the hearing and by letters and telephone calls to participants that a shorter period was required to maintain the schedule necessitated by the high priority of the Proposal; OSHA stated that it did not think this would be unfair to participants (Exs. 60-9, 81 A). By Federal Register notice of September 7, 1988, (53 FR 34708; Ex. 100), the Secretary of Labor set October 7, 1988, for post-hearing evidence and October 31, 1988, for post-hearing briefs. (This matter is discussed more fully in the Section III, Legal Authority.) OSHA received 57 post-hearing submissions from public participants totaling approximately 9000 pages. OSHA also received 41 post-hearing briefs. The total record includes substantially more than 4000 separate documents (individual studies, statements, comments, etc.).

The record was closed and certified by the presiding officer on November 10, 1988.

C. Details of Approach Used to Develop Regulation

The first step OSHA took to increase the pace of the regulatory process was to make a determination not to analyze individual substances in order to decide if they were of sufficient priority to be included in the project. Rather OSHA reviewed existing data bases and lists of recommended exposure limits, and determined which of these should be the starting point for the Proposal.

OSHA concluded that the National Institute for Occupational Safety and Health's (NIOSH) Recommended Exposure Limits (RELs) and the American Conference of Governmental Industrial Hygienist's (ACGIH) 1987-88 Threshold Limit Values (TLVs - a copyrighted term) provided the best two lists of substances to be considered for regulation and to provide a starting point for individual substance permissible exposure limits (PELs). See the discussion at 53 FR 20966-7. These lists of substances are developed by organizations of experts very knowledgeable both about the American work place and the health literature. See the testimony of Mastromatteo (Ex. 22) and NIOSH statement (Ex. 8-47). Both NIOSH and ACGIH publish documentation to support their recommendations and permit outside participation in the development of exposure limits.

Based on further analysis, the ACGIH TLVs were picked as the single best list to define the substances to be included in this rulemaking. The details of this OSHA analysis are provided in the Proposal (53 FR 20966-20967) and will not be repeated here. OSHA's major reason was that the TLVs are more extensive than the RELs and more generally used. There are over 600 TLVs and approximately 160 RELs.

By using the ACGIH list of TLVs as the basis for the selection of substances to be considered for this regulation, OSHA has greatly reduced the time it would take to proceed with this rulemaking. The ACGIH's list is broad in scope, attuned to the American workplace and developed by experts with substantial health expertise. Therefore, OSHA concludes that this approach to determining which substances will be considered for regulation is rational and allows OSHA to expedite the process of improving the health of American workers.

No changes to existing limits were considered in this rulemaking for substances covered by limits established in substance-specific 6(b) rulemaking (24 substances) or substances for which the process of 6(b) rulemaking has already been initiated (9 substances). Since OSHA had already begun the process of detailed analysis of these substances, additional review was determined to be unduly repetitive and confusing at this point.

OSHA then compared the permissible exposure limits in Tables Z-1, Z-2, and Z-3 to the TLV list. If the TLV and OSHA permissible exposure limits in the Z-Tables were identical, the substance was not considered for change of PEL in this proposal. The basis for this approach is that there is less likelihood to be a need for a change in an exposure limit if an organization which regularly reviews the literature has not changed its recommendation.

If the TLV and the PEL differed, the substance was considered for change of PEL in this rulemaking. Also substances for which there was a TLV, but no PEL, were included in this rulemaking. There is additional elaboration on this methodology in Section IV. D., Boundaries to Regulation.

The second approach OSHA used to shorten the rulemaking process was to rely to a greater extent than in the past on research and recommendations already made by NIOSH and ACGIH as a starting point for OSHA's analysis.

Both organizations have experts undertake a complete review of the literature for individual substances. Then they propose recommendations and permit outside comments on their proposed recommendations. At the next stage, each has a committee of experts again review the literature, as well as the comments on the initially published recommendations before determining the recommended exposure limit.

The approach OSHA followed was to first determine if the ACGIH-TLVs and NIOSH RELs were similar. If they were, or if there was no NIOSH REL, then OSHA reviewed the ACGIH documentation and recommendation. The ACGIH documentation includes summaries and analyses of the major studies. If the REL and TLV differed significantly, OSHA reviewed the studies and reasoning upon which both NIOSH and ACGIH recommendations were based, and then chose the recommendation which in OSHA's view was more appropriate.

In its review OSHA determined first whether the studies and analyses were valid and of reasonable scientific quality. Second, it determined, based on the studies, if the published documentation of the REL or TLV would meet OSHA's legal requirements for setting a PEL. Thus, OSHA reviewed the studies to see if there was substantial evidence of significant risk at the existing PEL or, if there was no PEL, at exposures which might exist in the workplace in the absence of any limit. Third, OSHA reviewed the studies to determine if the new PEL would lead to substantial reduction in significant risk. If this was so, and if the new PEL was feasible (see discussion below), OSHA proposed the new PEL.

OSHA then divided the chemicals into 18 categories, generally by health effect but, in a few instances, by other criteria. These categories included cardiovascular, liver-kidney, respiratory and other types of diseases or material health impairments. Each of these categories received an individual literature review and discussion in the preamble analyzing the etiology of substances which cause that health effect.

Some substances have several effects; the category chosen for each substance was based on the health effect which most influenced the exposure level proposed. However, OSHA individual discussions and conclusions referenced and were based on all health effects associated with the specific substance.

Following each general discussion in the preamble, OSHA summarized the documentation and provided references for each individual substance and stated the reasons for the proposed new exposure limit. OSHA also stated the reasons why it preliminarily concluded that the proposed new limit would substantially reduce significant risk for that substance. In the case of 25 substances, OSHA explained why after review it did not propose a new exposure limit. In one instance OSHA indicated the reasons for proposing to raise a limit.

This method fully informed the public of the basis for OSHA's decisions. The public was then in position to support or challenge OSHA's proposal, to criticize the studies upon which OSHA relied, and to supply any additional studies, evidence or views during the comment period, during the hearing or as post hearing submissions.

OSHA is gratified by the degree of support for the proposal expressed by rulemaking commenters. For example:

We believe this proposal is one of the most significant steps taken by OSHA since its inception. The time and resources required for substance specific rulemaking have greatly limited the number of PELs that OSHA has been able to revise since they were adopted in 1971. Continuing individual rulemaking would result in adding to the backlog of outdated PELs, while the method chosen by OSHA for this revision assures that comprehensive update will be completed within a reasonable time (Tr. August 2, Testimony of Tamarelli; SOCMA).

CMA supports the concept of revising the Z Table PELs in order to conform with the threshold limit values, TLVs, that have been adopted or updated by the American Conference of Governmental Industrial Hygienists...It is hard for us to understand how anyone could say that the proceeding is too limited in scope. To the contrary, a much more valid criticism might be that OSHA has bitten off more than it can chew. The Agency quite reasonably has concluded that adjusting the permissible exposure limits for chemicals on the TLV list should be its first order of business (Tr. August 10, Testimony of Lynch/CMA).

OSHA has taken a truly significant step in updating and enhancing the regulatory provisions applicable to the workplace...OSHA was prudent in our view to rely on the ACGIH TLVs to establish the bounds of the rulemaking (Tr. August 9, Testimony of Holthouser/RMA).

GE strongly supports and endorses the Occupational Safety and Health Administration's 6(b) rulemaking efforts to revise and upgrade the Z Tables in 29 CFR 1910.1000 and encourages everyone concerned about employee health, along with those involved in the rulemaking effort, to pursue a timely conclusion to the process (Tr. August 9, Jones/GE).

The American Industrial Hygiene Association (AIHA), on the other hand, was entirely in favor of OSHA's use of either an ACGIH or NIOSH limit, as the case requires:

AIHA supports the adoption by OSHA of NIOSH REL values as PELs on a case-by-case basis where such values are supported by the scientific evidence and are feasible from the standpoint of implementation (Ex. 8-16).

NIOSH expressed strong support for this rulemaking in general but submitted specific comments on a number of substances that it believes should have different limits from those proposed (Ex. 8-47). NIOSH's substance-specific comments are addressed in connection with the preamble discussion of these substances in Section VI.

Union representatives concurred with the need to update the Z-Tables. For example, M. Seminario/ AFL-CIO stated: "We are pleased that OSHA and many industry representatives have acknowledged finally that the current permissible exposure limits do not protect workers, and we do indeed support regulatory action to update the standards for toxic substances through the use of broad-based rulemaking such as the Agency has proposed here. (Tr. August 4, Testimony of Seminario/AFL-CIO).

However, Ms. Seminario did not agree with the approach that OSHA followed stating that "it does not provide the workers with the kind of protection that the OSHA Act requires." Union representatives stated that the proposed standard was not adequate since it did not cover some substances of concern and did not include the ancillary provisions which they felt were important.

OSHA does not agree with this judgment. It is impossible to cover all substances, and OSHA has made a rational and reasonable judgment regarding the bounds of this standard which is supported by most industry and professional associations. OSHA is approaching the subject of ancillary provisions through separate generic rulemakings which have already been initiated. The basis of these judgments are discussed in detail in other parts of this preamble.

OSHA stated in the proposal that it would consider all the additional views and studies presented by participants. Based on what was best supported by the entire record, OSHA would issue as the final standard either the PEL it had proposed, make no change to the existing PEL, or issue a different PEL. OSHA has followed this method of analysis in issuing the final rule.

OSHA's approach has indeed made it possible to increase the efficiency of the regulatory process and issue new and revised PELs to protect the health of workers from a large number of substances which were unregulated, or for which existing exposure limits are out of date. It has also permitted OSHA to rely on the best available scientific information and its past experience, while giving the public both excellent notice and a full and fair opportunity to comment, submit additional studies and make recommendations.

The improved efficiency of this rulemaking effort has not come from sacrificing scientific validity. It has resulted from combining discussions by health effect, concentrating on major issues and studies, using as a starting point the research of expert organizations, and using public comments to bring to attention additional relevant studies and issues. OSHA has addressed in more detail those substances, issues and studies which have been identified in the comments as the most controversial.

Third, OSHA has increased the efficiency of its feasibility analysis. Its prior substance-by-substance, industry sector by industry sector, process-by-process approach would have resulted in a vast body of duplicative information in a multi-substance rulemaking. In addition, it would have made it impossible to update very many substances in a reasonable period because of the time and resources required.

OSHA followed several approaches to increase the efficiency of its feasibility analysis process. First, it made maximum use of existing information. OSHA's Integrated Management Information System (IMIS) is probably the largest source of accurate exposure date in the world. It has 77,000 exposure measurements, is organized by industry and process, includes judgments by compliance officers who are experts in industrial hygiene, includes the number of workers represented by each measurement, and is computer readable.

OSHA also used the two National Occupational Hazard Surveys (NOHS) by NIOSH. These are good sources of the number of workers potentially exposed to substances in each industry segment. OSHA also analyzed the large volume of data in various publicly available data bases on control technology for various substances, processes and industries. For the convenience of the public, much of these data were combined into four volumes which were made available to the public in the docket. OSHA also stated it would supply these data on computer tape if requested.

OSHA had these data reviewed by approximately twenty experts in industrial hygiene and industrial engineering. They made estimates of substances likely to be used and processes likely to be present in each industry sector covered by this regulation. These estimates were used as starting points. Much more extensive information was gathered in a nationwide survey of 5700 firms.

These experts also made estimates of the cost to reduce exposure based on scale of operation, type of process, and degree of exposure reduction needed. Standard source materials such as industrial manuals were used. Many processes are relatively standardized throughout industry and are used for a variety of substances. For example, vat mixing takes place for many substances in many industries. It can be uncontrolled without a cover and involve manual loading of dry chemicals. It can be partially controlled with covers and pump-loading of liquids. It can be fully controlled with enclosure, ventilation and automated loading and unloading. Likely exposures can be estimated by determining the amount of chemicals used and degree of existing controls. Costs can be generalized throughout much of industry from the size of the operation, estimated exposures, and the cost to go from one degree of control to the improved level of control needed to achieve the proposed reduction in exposures.

With this method of analysis, it is possible to make estimates of exposures, controls necessary, exposure levels which can be achieved and costs from data on substances and processes present and numbers of operations for each industry segment. This information is sufficient for determining technical feasibility and costs by industry segment. These data combined with publicly available sales and profit ratio data make it possible to estimate economic feasibility by industry segment.

To gather data on the substances present, types of processes, number of processes, and controls in place by industry segment, OSHA commissioned the largest survey it has ever conducted. Over 5700 questionnaires were administered throughout the covered industry segment based on statistically valid sampling techniques. A vast amount of information was received on substances present, processes used and controls in place.

OSHA concludes that this approach is accurate on an industry sector by industry sector basis for individual processes.

Overall, OSHA has a high degree of confidence that its estimates of technical feasibility, costs and economic feasibility are accurate. OSHA has had far more data available to it than it normally does in a single substance rulemaking. The data were gathered systematically and were combined using a methodology that was statistically valid and devised by persons with great expertise.

In addition, to increase the efficiency of the process, OSHA analyzed the feasibility of the specific proposed exposure level for each substance rather than considering a variety of different exposure levels.

To permit public comment on this approach and related data in an efficient manner, OSHA published the entire Preliminary Regulatory Impact Analysis with the Proposal in the Federal Register. In addition, it made available to the public in the docket at the time of publication six supplements which described in great detail the methodology and results of the survey by sector.

OSHA concludes that it provided the public with all the information participants would need to comment on, criticize or support OSHA's feasibility conclusions. However, some participants requested more detailed analysis of their sectors. Although OSHA indicated that it believed the data it had made available were sufficient for these purposes, it did where possible supply additional data and make special computer runs when requested by the participants.

OSHA also stated it would consider all additional feasibility data submitted by the public. Many participants did supply additional data. OSHA has reviewed all data in the record in reaching its final feasibility conclusions.

OSHA concludes that the approach it took developed good feasibility data, permitted participants a reasonable opportunity to review OSHA's data and supply their own, and was necessary to make the feasibility analysis process more efficient.

The fourth difference in approach from single substance rulemaking was OSHA's decision to limit this rulemaking to the issue of exposure limits. OSHA has not considered medical surveillance, exposure monitoring, industrial hygiene requirements and other ancillary provisions which were not included in the existing 6(a) standard.

As stated in the Preamble, OSHA has concluded that the highest priority for protecting occupational health is to lower exposure limits for many substances where current knowledge indicates they are too high, or where currently there are no limits but recent scientific knowledge indicates limits are needed. This priority could not be achieved if ancillary provisions were considered at the same time. As discussed in Section III, Legal Authority, OSHA believes it is a rational use of its priority setting power to consider ancillary provisions subsequently either in other generic rulemakings or in substance specific Sec. 6(b) rulemakings. It has already begun that process as discussed there. In any event, OSHA's approach significantly improves occupational health protection.

A final method OSHA has followed to make this rulemaking more manageable is to rely on its experience. OSHA has now made feasibility determinations for several dozen substances and significant risk determinations approximately one dozen times. Various issues regarding the analysis of data have been reviewed many times. OSHA's approaches have been reviewed by the courts and upheld or modified to meet judicial guidance. OSHA has not revisited all of the issues in quite the depth it has given them in the past in light of its experience. Of course, determinations and conclusions required by law have been fully analyzed and supported. OSHA concludes it is both rational to rely on its past experience and specifically permitted by Section 6(b)(5) of the Act.

In the most important areas OSHA has not made any attempt to make the regulatory process shorter. First, as discussed, it included individual substance-by-substance health analyses and significant risk determinations. Second, it has made feasibility determinations on the impact of the regulation of all the substances for each industrial sector.

Third, OSHA has followed its traditional elaborate rulemaking process. Nine months advance notice of the intent to issue a proposal was given. The Proposal explained OSHA's reasoning at great length by citing and discussing the evidence upon which OSHA relied. All the studies and analyses upon which OSHA relied were made available in the docket. More than the minimum period was allowed for comments.

Thirteen days were allowed for oral hearings. Testimony and evidence was required to be submitted in advance and the testimony of OSHA, its economic contractors and witnesses was made available in advance. Participants in the hearings were permitted to question the OSHA panel, contractors, witnesses and each other. Though the questioning permitted for each participant was not unlimited, time was provided at the end to ensure that each participant had completed all questioning he or she desired. As there were frequently more than 10 participants who questioned a single witness, the total amount of questioning was often extensive. The OSHA panel was questioned for approximately four hours and the economics panel for more than six hours. Various arrangements were made to bring back witnesses.

After the hearing, participants were allowed to file post-hearing evidence to respond to comments and testimony, and to supply materials which they could not submit by the deadline for comments. An additional period was allowed for post-hearing briefs.

These are far more than the minimum procedural requirements of informal rulemaking or hybrid rulemaking. Few if any agencies, for example, permit questioning of the agency and its contractors. The process also effectively permits participants a double round of comments.

The various time frames were shorter than some participants desired. However, there was approximately one year between initial notice and final opportunity for submissions and approximately five months from proposal to post-hearing briefs. Not only is this far more than the legal minimum, but it should have been ample to give sufficient time for participants to effectively present their views and supporting evidence.

Adhering to a schedule is crucial for an agency to accomplish a high priority, large scale project in a reasonable period of time. Among other reasons for this is the fact that extra staff must be borrowed and contractor assistance arranged. Both groups have other schedule commitments. If a rulemaking is delayed too long these resources become lost to the project. Consequently, medium length delays during the public participation period become very lengthy delays of a final rule. As OSHA has pointed out, the benefits of this standard to worker health are so significant that lengthy delays of the final rule would result in a major loss in health protection.

Finally, OSHA has fully met the requirements pursuant to statute and executive order to perform required analyses. OSHA has completed the Regulatory Impact, Regulatory Flexibility and other analyses as required.

D. Boundaries to Regulation

The Proposal defined the substances covered by this rulemaking as a sub-set of the substances listed in the 1987-88 Threshold Limit Values (TLV) published by the American Conference of Governmental Industrial Hygienists (ACGIH), (53 FR 20964-20966). OSHA pointed out in the Proposal that the TLV listing had several advantages over other possible lists that might be used for this purpose. Details of the OSHA analysis leading to this decision are noted in the Proposal (53 FR 20966-20967). The primary considerations leading to that OSHA decision were (1) number of substances covered by the TLV listing; (2) available written documentation for the TLVs; (3) potential employee exposures covered by TLVs; and (4) general acceptance of the TLVs by health professionals.

OSHA realized that there are different valid approaches to the question of identifying the boundaries for this type of rulemaking, and any decision must balance completeness with practicality. Several commenters recommended that the number of substances considered in this rulemaking be expanded to include: (1) other lists; (2) the 160 substances in the existing Z-Tables which were not discussed in the Proposal since their current TLVs were identical with the existing OSHA PEL; and (3) substances which are in the process of active (6b) rulemaking.

Relative to the first point, the additional lists suggested included the following data bases: (a) Recommended Exposure Limits (REL) developed by the National Institute for Occupational Safety and Health; (b) Workplace Environmental Exposure Limits (WEEL's) developed by the American Industrial Hygiene Association; (c) EPA's Integrated Risk Information System (IRIS); (d) standards used by government agencies in the U.S.S.R. and other parts of eastern and western Europe; and (e) internal company limits. The following comments focus on this aspect: Ex. 8-47 (NIOSH), Ex. 43 (Frumin), Ex. 194 (AFL-CIO), Ex. 3-9 and Ex. 46 (Ziem), Ex. 42 C and 197 (UAW). Dr. Phillip J. Landrigan suggested (TR August 1, Test. of Landrigan): (a) using a single alternative listing instead of the TLVs; (b) combining several lists to define the bounds of this rulemaking; or (c) adopting a smaller sub-set of the TLVs.

During the public hearing it was suggested that benefits would result from developing PELs for additional substances. Specific substances suggested for inclusion in this rulemaking included dimethylformamide (Ex. 47); polychlorinated biphenyls (Tr 7-123); and glycol ethers (Ex. 3-639).

OSHA considered these constructive suggestions intended to expand the scope of this rulemaking in an effort to improve the level of health protection afforded workers. OSHA realizes that there are various approaches to this type of rulemaking and believes that, while some of these suggestions have merit, they introduce untenable problems at this stage of the rulemaking process. OSHA has determined that it is preferable to consider some of these suggestions as part of possible follow-on rulemaking based on the following facts and analyses.

For many of the additional substances provided by these data bases there are no quantitative exposure limits (e.g. IRIS and some NIOSH RELs). For other substances it is not clear that the limits are actually applied to workplace compliance situations (e.g. U.S.S.R. and eastern Europe limit). For others, (internal corporate limits) an extended independent review procedure is not defined. Use of a multiplicity of data bases to define the bounds for this already large rulemaking would overwhelm the resources of OSHA and those concerned parties who wish to comment on any proposed changes. This would greatly delay prompt implementation of a regulation which is urgently needed to protect the health of approximately 17 million workers who are potentially exposed to the 428 substances for which revised PELs were considered in the Proposal. Additional delay would be necessary since OSHA would be required to publish a new Proposal for any substances not identified and discussed in the Proposal.

The record clearly shows that OSHA's decision to use the ACGIH TLVs as the bounds for this effort was generally supported by most commenters for a variety of reasons: Ex. 3-866 (ORC); Ex. 3-740 (ARCO); Ex. 3-741 and 196 (Dow); Ex. 170 (GE); Ex. 3-891 and 176 (SOCMA); Ex. 178 (API); Ex. 3-877 and 47 (RMA); Ex. 52 (HIMA) Ex. 3-678 and 58 (Abbott); Ex. 163 (Ergon Refining), Ex. 186 (Halogenated Solvents Industry Alliance) and Ex. 165 (CMA). These reasons include the general acceptance and probable feasibility of the TLVs, and the need to have clearly defined limits for this rulemaking so it can be concluded in a reasonable time period.
For example, Jeremiah Lynch speaking on behalf of CMA stated:
It is hard for us to understand how anyone could say the proceeding is too limited in scope... The Agency quite reasonably has concluded that adjusting the permissible exposure limits for chemicals on the TLV list should be its first order of business. Further refinements in the regulation of these chemicals can be dealt with at a later date, to the extent additional requirements are found to be necessary. (Ex. 64).

It is necessary to limit the number of substances included in this rulemaking so that it can be completed in a reasonable time frame. The total number of chemicals in existence is well over 100,000. The 1985-86 edition of the NIOSH Registry of Toxic Effects of Chemical Substances (RTECS; DHHS (NIOSH) Publication No. 87-114) contains 88,693 prime chemical substances. It is impossible to promulgate an OSHA regulation without limiting the number of substances under consideration to manageable proportions. In this regulation such limitations are based on several considerations including the: (1) extent of use in commerce; (2) potential for exposure; and (3) lack of any existing protective limits. The first two criteria are best satisfied by using the well established TLVs as the data base for defining inclusion in this rulemaking. Since the number of substances in the TLV listing would still overwhelm the available resources, OSHA determined that it was reasonable to defer for consideration at a later time those 160 substances for which an OSHA PEL already exists and for which no change in TLV has occurred.

Such exclusion from consideration of change of PEL in this rulemaking does not preclude OSHA from initiating 6(b) rulemaking in the future for any of these substances or for any of the other substances covered by this regulation. Because of this fact, OSHA believes that its initial decision not to consider changing the PEL for those substances where the 1987-88 TLV is identical with the existing OSHA PEL is appropriate.

OSHA also believes that it would unnecessarily complicate this rulemaking as well as the individual rulemakings if changes to existing PELs were considered at this time for the nine substances for the which the 6(b) rulemaking process has already been started. The process of developing a 6(b) standard for a single substance differs from the process used in this proceeding since it involves consideration of various ancillary requirements (exposure monitoring, medical surveillance, use of personal protective equipment, labeling, etc.) which are not part of this rulemaking. Extensive dockets have already been developed for the nine substances in this category (Table IV-D-1). Since these 6(b) rulemakings should be completed in the near future as tentatively scheduled by the Regulatory Agenda (52 FR 4044-40542), it would unnecessarily complicate the rulemaking process without any significant benefit if these nine substances were included in this rulemaking.

Until the new regulations for these nine substances are adopted, the existing OSHA PELs will remain in effect as reflected in Table Z-1-A. This same procedure is also used for the 160 substances where the existing PEL is identical with the 1987-88 TLV, and for which new PELs are not proposed in this rulemaking. These 160 substances were listed in Table VII-D of the Proposal (53 FR 21254-21261).

It should be noted that no changes in PEL have been proposed for the 24 substances listed in Table VI-D-2 which are covered by individual 6(b) regulations. The existing PELs for some of these substances are incorporated into the Z-1-A Table both for reference purposes and because the individual 6(b) regulations for some of these substances do not cover all operations, making maintenance of these PELs necessary to provide protection to workers involved in these exempted activities (e.g. benzene, cotton dust, and formaldehyde).

While the TLVs and RELs were used as a starting point for defining PELs, it should be noted that OSHA made its own determination regarding each individual limit. This was based on further evaluation of: (a) the TLV Documentation and the Criteria Document supporting development of the REL; (b) submissions to the public hearing record; and (c) information used in developing some of the other data bases initially considered by OSHA in developing the Proposal.

For a few substances, commenters suggested that it would be preferable to delete a particular substance from this rulemaking and consider it as part of a separate single substance rulemaking. Such comments were specifically directed at wood dust (Ex. 3-748), grain dust (Ex. 3-752 and 3-755), sulfur dioxide (Ex. 8-65), and styrene (Ex, 3-742).

In the case of wood dust and grain dust it is imperative that OSHA act promptly since there is no existing accepted PEL for organic dusts. The Occupational Safety and Health Review Commission has held that the standard for nuisance dusts is not to be applicable to wood dust and grain dust. To initiate and complete a 6(b) standard to control these substances would take considerable time. Since there is a clear need for a PEL to protect against the significant risk associated with exposures to wood dust and grain dust, and there is now sufficient health and feasibility data to justify setting a PEL, it is imperative that OSHA act promptly to protect workers exposed to these hazardous substances. The analyses of these data are provided in the discussion of these substances in Section VI. In the case of wood dust, the Inter-Industry Wood Coordinating Committee indicated their concurrence regarding adoption of a 5 mg/m(3) standard, which represents part of the standard OSHA is proposing for wood dust. (Ex. 3-748 and 80).

In the case of sulfur dioxide, the commenter indicated that deletion was appropriate due to the existence of a past record (Ex. 8-65 and Docket No. H-039). OSHA agrees that the past public record must be considered, and has incorporated the previous SO(2) record into the record for this rulemaking (Ex. 10-45). OSHA has carefully considered all relevant information from the previous SO(2) record in making its decision regarding a PEL for sulfur dioxide, and the OSHA analysis of that record is included in the discussion establishing the PEL for sulfur dioxide.

In the case of styrene, acrylamide, and a few other substances, questions were raised regarding the adequacy of available information to develop a PEL in this rulemaking. Questions were raised regarding definition of carcinogenicity, feasibility (economic and technological), proper classifications of health effects, and the proper PEL (Ex. 3-742 and 70). In some instances, OSHA believes that sufficient information was not available to reach a final determination regarding carcinogenicity. However, information submitted by the commenters, together with material considered in the development of the Proposal, was adequate to permit OSHA to reach a conclusion regarding the PEL. The details of these analyses are included in Section VI.

In some instances OSHA has specifically indicated that a specific revised PEL may not fully eliminate significant risk of material impairment. In many instances this is due to information and data limitations noted in the discussion for that specific substance. However, the PEL is based on the best current interpretation of data available at the time of promulgation of the regulation. A PEL may change as more information becomes available, or more accurate analytical procedures are developed. As an example, the PEL for asbestos initially adopted in 1971 was revised in 1972. This level was modified in 1976 and revised again in 1986.

After due consideration of all suggestions to delete substances from this rulemaking, OSHA has determined that the only substance to be deleted from this rulemaking is chromyl chloride for which a PEL was considered but not adopted because OSHA had not given adequate notice in the Proposal. In the case of three other substances (asphalt, fibrous glass and mineral wool), a decision regarding a specific PEL is being delayed. OSHA has discussed the reasons for adopting each PEL in Section VI of the preamble to this standard.

As part of the public hearing submissions and presentations, several individuals suggested expansion of the rulemaking to include provisions for exposure monitoring and medical surveillance; Ex. 8-3 (Landrigan); Ex. 194 (AFL-CIO); Ex. 3-751 (Food & Allied Service Trades Dept.); (Ex. 42 and 197 (UAW); Ex. 43 (Frumin); Ex. 8-61 (Workers Institute); and 8-85 (Melius). OSHA has adopted ancillary provisions for each substance regulated through 6(b) rulemaking. After 17 years, these provisions are included in only the 24 existing individual substance OSHA standards. OSHA finds that this rulemaking is not the appropriate mechanism for extending the ancillary provisions to all substances covered by the Z-Tables and agrees with the following comments of PPG and Dow:

Further expansion of this rule to specifically impose additional regulatory requirements such as medical surveillance, recordkeeping, personal protective equipment, and training would unnecessarily complicate and confuse the main objective of this proposed rule. There is also a greater likelihood of challenge that has been an impediment to previous attempts to revise air contaminant levels such as the Standards Completion Progress Project." Ex. 3-1158 (PPG) While we believe OSHA should not adopt medical surveillance and exposure monitoring provisions in this rulemaking, we do believe OSHA should promulgate generic medical surveillance and exposure monitoring standards in a timely fashion. Ex. 169 (Dow)

On September 27, 1988, OSHA published Advance Notices of Proposal Rulemaking (ANPRM) covering "Generic Standards for Exposure Monitoring (53 FR 32591-32595) and "Medical Surveillance Programs for Employees (53 FR 32595-32598).

It was pointed out by Dr. I. Rosenthal, Rohm and Haas Co., that "if in the future OSHA supplements up-to-date exposure standards with generic how-to standards addressing medical surveillance, monitoring, personal protective equipment and other similar items the Agency will have established over 400 defacto complete standards." (Ex. Tr. 3-17). OSHA therefore believes that consideration of exposure monitoring and medical surveillance is best achieved through the generic approach which has been initiated with the two September 27, 1988, ANPRM's.

The legal and policy justification for limiting this rulemaking to development of PELs is detailed in the Legal Authority Section of this Preamble. The appropriateness of addressing PELs prior to considering ancillary provisions was also endorsed on technical grounds by Dr. Marcus Key, former Director of NIOSH (Ex.- TR 1-233, TR 1-265; TR 1-266).

Several commenters were concerned with the computational formula presently noted in 1910.1000 (d)(2), for example, Ex. 3-742 (SIRC); Ex. 3-877 (RMA) and Ex. 165 (CMA). These concerns relate to the lack of a requirement that this formula should apply only to those situations in which an additive effect is present. In contrast, the ACGIH discussion of the Threshold Limit Value for Mixtures (TLV and BEI for 1988-89, p. 42) states that this equation is applicable, "when two or more hazardous substances, which act upon the same organ system, are present, their combined effect, rather than that of either individually, should be given primary consideration." This reference goes on to state that "exceptions to the above rule may be made when there is a good reason to believe that the chief effects of the different harmful substances are not in fact additive, but independent as when purely local effects on different organs of the body are produced by the various components of the mixture."

The Proposal only redesignated paragraph 1910.1000 (d) as 1910.1000 (f) (53 FR 21263), a change which is no longer necessary. There was no intent to reconsider or clarify this paragraph as part of this rulemaking. This subject was not discussed in the Proposal and was not a topic for consideration as part of this rulemaking. Therefore, it is not appropriate to consider any changes to the mixture equation at this time.

During the Public Hearing a few commenters made specific suggestions regarding other expansions to the subjects covered under this rulemaking. These included:

(1) Expansion of the PELs to non-traditional work shifts (TR 3-231 3-234 (Arco)). OSHA is aware that work schedules in excess of 8 hrs/day are becoming more common. However, it is clear that this rulemaking did not provide an appropriate platform for full discussion of the technical problems associated with adjusting PELs for work shifts other than an 8 hr/day. It appears that such a question is highly substance specific depending on the toxicology and body clearance mechanisms, and the significance of short term exposure peaks. As such it may be more appropriate to provide guidance in the form of an interpretation of acceptable alternate approaches to extrapolating the 8 hr. PEL to other work shift periods. This might be developed through the OSHA Industrial Hygiene Technical Manual or the Field Operations Manual so it could be implemented on a case-by-case basis. OSHA believes that this type of expansion of a Proposal intended to address only PELs is not justified. The use of RELs developed using a 10 hr. definition for developing 8 hr TWA PELs is supported by NIOSH testimony (Ex. 8-47) and this approach has been used in this rulemaking.

(2) Representatives of the Workers Institute for Health and Safety suggested incorporating surface contaminated limits, such as those recommended by NIOSH and EPA for polychlorinated biphenyls (PCB) that are used in the clean-up of the New Mexico State Highway Department Building (TR 7-123 and 7-124). Clearly this represents an exposure index which is significantly different from "Air Contaminants" which is the subject of this Proposal. OSHA therefore concludes that extension of this rulemaking to include consideration of surface contamination limits is not appropriate.

(3) Mr. Richard Henderson representing the Chlorine Institute recommended that, rather than reducing the PEL for mercury, OSHA maintain the existing PEL and develop a comprehensive standard which includes a requirement for periodic urinary mercury determination. The question of the appropriate PEL for mercury is discussed in Section VI of this preamble. Regarding the suggestion of urinary measurements which could be considered for many substances other than mercury, OSHA finds that this represents an exposure index which is significantly different from "Air Contaminants", the subject of this rulemaking. OSHA concludes that extension of this rulemaking to cover this subject is not appropriate.

In summary, OSHA has reviewed all comments to the record which might result in changes to the boundaries of the rulemaking defined in the Proposal. OSHA finds that the suggested additions and deletions would not be appropriate in light of the objectives for this rulemaking established by OSHA and dictated by the statutory requirements of the OSH Act.

Therefore, OSHA concluded that the 428 substances listed in Table I-E of the Proposal (53 FR 20968-20976) should be considered for change in the PEL as part of this regulation. These substances are listed in the Index-Locator Section (II) of this preamble.

The Z-1-A Table in this regulation also incorporates the existing PELs for: (1) the 160 substances from the existing Z-Tables, which were not considered for changes in the PEL; (2) 9 substances for which 6(b) rulemaking is in progress; and (3) some of the 24 substances covered by individual OSHA standards where some sectors are not covered by the individual substance standard.

The Z-1-A Table lists all substances covered by this regulation, whether or not the PEL has been changed, whether or not a 6(b) standard has been undertaken on a specific substance, and whether or not a 6(b) standard covers the substance either fully or partially. In the case of substances regulated by individual substance OSHA standards, the Z-1-A Table cross references the individual standard.

Table IV-D-1 Substances for which OSHA Has Initiated 6(b) Rulemaking.


Cadmium Dust and Fume
2-Ethoxyethanol (Cellosolve)
2-Ethoxyethyl Acetate
Ethylene Dibromide
Methyl Cellosolve
Methyl Cellosolve Acetate
Methylene Chloride

Table IV-D-2.  Substances Regulated by OSHA Under Section 6(b).

2-ACetylaminofluorine         1910.1014
Acrylonitrile                 1910.1045
4-Aminodiphenyl               1910.1011
Arsenic (Inorganic)           1910.1018
Asbestos                      1910.1001
Benzene                       1910.1028
Benzidine                     1910.1010
Bis-Chloromethyl Ether        1910.1008
Coke Oven Emissions           1910.1029
Cotton Dust                   1910.1043
1,2-Dibromo-3-Dichloropropane 1910.1049
3,3'-Dichlorobenzidine        1910.1007
4-Dimethylaminoazobenzene     1910.1015
Ethylene Oxide                1910.1047
Ethyleneimine                 1910.1012
Formaldehyde                  1910.1048
Lead                          1910.1025
Methyl Chloromethyl Ether     1910.1006
2-Naphthylamine               1910.1004
3-Naphthylamine               1910.1009
4-Nitrobiphenyl               1910.1003
n-Nitrosodimethylamine        1910.1016
b-Propiolactone               1910.1013
Vinyl Chloride                1910.1017

E. Special Considerations

In the Proposal several substances were identified (53 FR 20978, Tables I-F-A, I-F-B, I-F-C and I-F-D) as requiring special attention. This was due to the presence of "significant differences" between the exposure limits recommended by the various data bases initially considered in this rulemaking. This same Section of the Proposal also identified some basic assumptions used to initially simplify the definition of "significant difference." The objective of this effort was to encourage comments during the Public Hearing process for those substances where there was greater potential for uncertainly regarding the proposed PEL.

Comments were received on some of these substances. NIOSH (Ex.8-47) commented on all those substances for which a REL existed, as well as for many other substances noted in these four Tables. Extensive comments were submitted regarding the proposed PELs for Acetone (Ex. 8-54, 3-69, 3-661, 3-741, Tr. VI pp. 89-247); Acrylamide (Ex. 3-961); Carbon disulfide (Ex. 8-19, 8-45, 3-659, 3-674, 3-897, 3-945, 3-1158, 3-753); and Sulfur dioxide (Ex. 3-1123, 8-22, 8-57, 8-65, 3-349, 8-9). A considerable number of comments were also directed at the selection of RELs (SOCMA, Exs. 3-891 and 176; Dow Chemical, Ex. 3-741; Rubber Manufacturers, Ex. 3-877). For example, GE (Ex. 170) stated:

It is apparent from the testimony given during the hearings and comments submitted into the rulemaking record that the Recommended Exposure Limits (RELs) are a source of considerable controversy...a wide cross-section of occupational health professionals from industry, government and academia believe there are substantial flaws in the contract process under which NIOSH RELs were developed, including limitations in peer reviews, feasibility considerations, and the methodologies employed in extrapolating animal toxicological data and limited epidemiology findings to workplace exposure limits. (Ex. 170)

NIOSH pointed out that "Each Criteria Document is reviewed by experts representing affected industries, organized labor, and trade or professional organizations, and by scientists, physicians, and other health professionals with related experience in academia, government, or industry. The number of these external peer reviewers normally is greater than 10 and often exceeds twice that number. In addition to the invaluable contribution their comments make to the completed Criteria Document, OSHA receives, along with the completed Criteria Document, the full text of each reviewer's written comments accompanied by itemized annotations indicating how the draft was modified in response, or providing the rationale if the comment or recommendation was not adopted. Each Criteria Document contains an extensive summary in which the basis for the Recommended Exposure Limit (REL) is carefully developed with clear and explicit citation of the data relied upon at all steps of the logical development. No other source of exposure limits approximates the comprehensiveness of these documents." OSHA believes that its use of the RELs in this rulemaking is appropriate.

These submissions achieved the OSHA objectives of stimulating the input of new data, analyses, and information to assist OSHA in this rulemaking based on the full record for each individual substance. The discussion and application of this information to set specific PELs is included in the individual substances discussions in Section VI of this Preamble.

While OSHA did initially identify basic assumptions regarding significant differences (53 FR 20977), the final OSHA decision regarding selection of a specific PEL is based on a case-by-case assessment of the health effects, significant risk, material impairment of health, available sampling and analytical methods, and technological and economic feasibility considerations.

Another special consideration was the question of dealing with substances for which there are sampling and analytical limitations (Table I-F-E of the Proposal, (53 FR 20978)). This was also identified as a concern in Question 9 of the Proposal (53 FR 20961). The responses to this question are detailed in Section V of this Preamble. OSHA concurs that adequate sampling and analytical methods are required to permit enforcement of a PEL. However, OSHA believes that an adequate sampling and analytical method exists when such methods are fully described in the open literature, or when otherwise readily available.

The Public Hearing did not provide much additional information regarding sampling and analytical methods for those substances identified as having inadequate sampling and analytical methods. However, a method was identified for substilisins and was entered into the docket (Ex. 8-70). Included in Table IV-E-1 of this section are the substances noted in Table I-F-E of the Proposal (53 FR 20978) and two additional substances (oxygen difluoride and phenylphosphine) which were inadvertently omitted from the listing of substances with inadequate sampling or analytical methods. One substance, cyanamide, was erroneously listed as having no method.

OSHA has also considered the concerns identified regarding the need for a more extensively tested analytical method (Ex. 3-960; Ex. 8-47) for enforcement purposes. OSHA believes that enforcement can be initiated without such detailed methods. The OSHA docket includes: (1) reference to a fully developed and extensively tested OSHA or NIOSH sampling and analytical procedure or, (2) a description of an OSHA in-house sampling and analytical method for all but the seven substances listed in Table IV-E-1. OSHA therefore believes there will be no problems with enforcement of the PELs for all but these seven substances. This is consistent with conclusions of NIOSH regarding implementation (Ex. 8-47). Since development of sampling and analytical procedures is a dynamic, rapidly progressing technology, OSHA also believes it is appropriate to adopt PELs for the seven substances (based on the Proposal and the Public Hearing record), but stay enforcement of these PELs until adequate sampling and analytical methods are available. At such time, OSHA will publish in the Federal Register its determination that such methods exist (together with a copy of the method), and indicate the proposed effective date for enforcement of the PEL for the substance in question.

As time, resources and priorities permit, OSHA will attempt to initiate a program, in conjunction with NIOSH, to develop more extensively tested sampling and analytical methods for those substances where only in-house methods are noted in the Proposal.

OSHA further considered the three alternative approaches described in the Proposal regarding interim procedures for handling those substances requiring special attention (53 FR 20978-20979). OSHA encouraged public comment on this subject by including a question (number 14) in the Proposal. The responses to this question are detailed in Section V of this preamble and indicate the desireability of implementing new PELs promptly, even if they represent only interim values.

Therefore, OSHA is proceeding to promulgate limits for all of the substances included in the Proposal where statutory requirements are met, while also identifying some substances which appear appropriate for future consideration.

                     Table IV-E-1

  Substances with Inadequate Analytical or Sampling Methods
1.  Aluminum alkyls
2.  Ethylidene norbornene
3.  Hexafluoracetone
4.  Mercury (alkyl compounds)
5.  Oxygen Difluoride
6.  Phenylphosphine
7.  Sulfur pentafluoride

F. Construction, Maritime and Agriculture Segments

Currently the exposure limits which apply to construction are the ACGIH Threshold Limit Values of Air Contaminants for 1970 and certain substance specific Sec. 6(b) standards. See 29 CFR 1926.55, 58 and 29 CFR 1910.19. OSHA is required to consult with the Advisory Committee on Construction Safety and Health prior to proposing new standards that have a major impact on construction. See 29 CFR 1911.10(a). OSHA is in the process of formally consulting with the Construction Advisory Committee. After receiving their recommendations and studying feasibility issues for construction, OSHA intends to propose amendments covering exposures to toxic substances in construction reflecting the facts in this final preamble and standard, and the views of the Construction Advisory Committee.

Parts 1916, 1917 and 1918 of 29 CFR cover, respectively, employment in shipyards, marine terminals and longshoring. Part 1916 for shipyards references the 1970 TLVs of the ACGIH. See 29 CFR 1915.5 and 1915.12 (b)(3). Part 1917 for marine terminals references the current Z-Tables. See 29 CFR 1917.2 (p), and .23. Part 1918 for longshoring refers to "dangerous gaseous contaminants not immediately dangerous to life" and "heavy concentrations of dusts." See 29 CFR 1918.93 (e) and (f). Certain substance specific Section 6(b) standards also cover these industries. See 29 CFR 1910.19.

OSHA, as part of the rulemaking covering construction and after studying feasibility for the maritime sectors, intends to consider applying the final standard to the maritime sectors.

Subpart Z of 29 CFR part 1910, and the included Z-Tables specifically do not apply to Agriculture. See 29 CFR 1928.21(b). In addition, many of the chemicals which affect agriculture are pesticides regulated by the EPA over which OSHA may not have jurisdiction, pursuant to 4(b)(1) of the OSHA Act. In the future OSHA will consider, based on relevance, priorities and administrative resources, whether or not it is appropriate to consider coverage for agriculture.

G. Federalism

This final regulation has been reviewed in accordance with Executive Order 12612 (52 FR 41685; October 30, 1987) regarding Federalism. Executive Order 12612 requires that agencies, to the extent possible, refrain from limiting state policy options, consult with states prior to taking any actions that would restrict state policy options, and take such actions only when there is clear constitutional authority and the presence of a problem of national scope. The Executive Order provides for preemption of state law only if there is a clear Congressional intent for the Agency to do so. Any such preemption is to be limited to the extent possible.

During the development of this rule, OSHA has, to the extent possible, refrained from limiting state policy options by developing a rule that permits flexibility on the part of the States through the use of performance language. OSHA also consulted with the States during the public comment and hearing period announced in the notice of proposed rulemaking for this rule. OSHA specifically invited Stephen Cant of the State of Washington to testify about the state's experience in a similar rulemaking. OSH will continue to work with the States that have state occupational safety and health plans approved under Section 18 of the OSH Act to encourage those states to develop their own policies to achieve program objectives and will continue to work with appropriate state officials as they present their state standards for approval.

Section 18 of the Occupational Safety and Health Act (OSH Act), permits any state to develop its own independent state occupational safety and health program that provides, among other things, worker protection "at least as effective as" that protection provided under the Federal program.

With respect to Section 4 of Executive Order 12612, Section 18 of the OSH Act also expresses Congress' clear intent to preempt state laws relating to issues with respect to which Federal OSHA has promulgated occupational safety or health standards. Under the OSH Act, a state can avoid preemption only if it submits, and obtains Federal OSHA approval of, a plan for the development of such standards and their enforcement as mentioned above. Occupational safety and health standards developed by such Approved Plan States must, among other things, be as least as effective in providing safe and healthful employment and places of employment as the Federal standards.

Under the OSH Act, if a state develops its own OSHA approved state program, it could include additional requirements in its standards. Moreover, the performance nature of this final rule, of and by itself, allows for flexibility by states to provide at least as much health protection, consonant with the conditions in each state.

In summary, there is a clear national problem, identified by Congress, related to occupational safety and health. While the individual states, if all acted collectively, might be able to deal with the health problems involved, most have elected not to do so in the seventeen years since the enactment of the OSH Act. However, some states such as Washington have taken action. Those states which have elected to participate under Section 18 of the OSH Act, would not be preempted by this final regulation and would be able to address special, local conditions within the framework provided by this standard while ensuring that their standards are at least as effective as the Federal standard. State comments were invited on the Proposal and those that were submitted to the record were fully considered prior to promulgation of this Final Rule.

The agency certifies that this document has been assessed in light of the principles, criteria, and requirements stated in sections 2 through 5 of Executive Order 12621. There are no provisions of this rulemaking that are inconsistent with the principles, criteria and requirements stated in Sections 2 through 5 of Executive Order 12621. States which have approved state occupational safety and health plans may incur additional costs associated with standards development and enforcement as a result of this rulemaking. Funding for these approved state plan programs is available from OSHA under section 18 of the OSH Act. This rulemaking would not change the State's ability to discharge traditional State governmental functions or other aspects of State sovereignty.

H. Glossary

The following terms and acronyms appear in the standard and the preamble supporting it. This glossary is provided as a convenience to the reader.

ACGIH - The American Conference Governmental Industrial Hygienists is a professional society devoted to the development of administrative and technical aspects of worker health protection. Membership is limited to professional personnel in governmental agencies or educational institutions engaged in occupational safety and health programs. The ACGIH issues guidelines and recommendations in the form of Threshold Limit Values (TLVs(R)) which are published annually.

CAS - The Chemical Abstracts Service (CAS) Registry Number is a numeric designation assigned by the American Chemical Society's Chemical Abstracts Service which uniquely identifies a specific chemical compound. This entry allows one to conclusively identify a substance regardless of the name or naming system used.

CHRIS - The Chemical Hazards Response Information System was developed by the U.S. Coast Guard in cooperation with the National Academy of Sciences to provide information on the handling and disposal of toxic substances. CHRIS consists primarily of the Hazardous Chemical Data Manual which contains chemical, physical and health hazard data on approximately 600 hazardous chemicals and substances; and a Hazard Assessment Computer System is an extensive data base of the information contained in the Hazardous Chemical Data Manual.

HSDB - The Hazardous Substances Data Bank, a part of the National Library of Medicine System, will soon be available on OSHA's Computerized Information System (OCIS). This data bank, currently available through TOXNET, contains health and safety profiles for over 4100 chemicals. It includes 144 data elements in 10 categories including use information, substance identification, animal and human toxicity, environmental fate, standards, personal protective equipment, fire, physical and chemical properties.

IARC - The International Agency for Research on Cancer (IARC) is a research organization authorized by the World Health Organization in 1965. IARC's mission is to study the causes of cancer in the human environment. IARC has published (and continues to update) a series of monographs on a substantial number of toxic chemicals and substance in which the carcinogenic risk of these chemicals is evaluated.

ILO - The International Labour Organization (ILO) is a specialized agency associated with the United Nations. Established in 1919 as part of the Versailles Peace Treaty, the ILO serves to band together governments, employers, and workers of 145 nations in an international effort to improve overall working conditions and to protect the life and health of workers.

IMIS - The Integrated Management Information System (IMIS) is a data base developed by OSHA in 1979 with sampling information on more than 70,000 individual measurements. The IMIS contains exposure measurements obtained by OSHA compliance officers during thousands of health inspections; it is the most extensive data base of its kind.

Material - The term "material" is used in the original standard whereas "substance" is used in the revision. The meaning is the same.

MSDS - The Material Safety Data Sheet (MSDS) is a compilation of data and information on individual hazardous chemicals produced by the manufacturers and importers of that chemical, as required by OSHA's Hazard Communication Standard, 29 CFR 1910.1200. An MSDS contains data on chemical identification, current exposure limits, chemical reactivity, fire and explosion limits, and information on health hazards and emergency procedures, spill, leak, and disposal procedures, and any needed special protection or precautions.

NIOSH - The National Institute for Occupational Safety and Health (NIOSH) was created by the Occupational Safety and Health Act of 1970. NIOSH is part of the Centers for Disease Control under the Department of Health and Human Services. Its mandate includes conducting research in developing criteria and/or recommendations to be used in setting occupational exposure standards, identifying and evaluating workplace hazards, measurement techniques, and control technologies, and providing professional education as well as health and safety information.

NOES - The National Occupational Exposure Survey (NOES) is a data base completed in 1982 by NIOSH. NOES is the successor to the first such data base, completed by NIOSH in 1974, and known as the National Occupational Hazard Survey (NOHS). The NOES data base contains a sample of the number of persons exposed by substance and industry from approximately 4500 businesses in 98 geographic areas in the U.S. These surveys provide national estimates of potential exposure to workplace hazards, by industry and occupational group.

OCIS - The OSHA Computerized Information System is a comprehensive data base that contains information and data on standards interpretation, chemical information, hazardous waste activity, 5(a)(1) citations, a health hazard evaluation index, training materials, and other information compiled by OSHA on subjects related to occupational safety and health.

OSHA HS Number - A Health Standard (HS) number is a 4-digit code assigned, for ease in reference, to each of the hazardous substances or chemicals considered for change of PEL in this rulemaking.

PEL - Permissible Exposure Limits (PELs) are limits developed by OSHA to indicate the maximum airborne concentration of a contaminant to which an employee may be exposed over the duration specified by the type of PEL assigned to that contaminant.

Proposal - Refers to the June 7, 1988, Notice of Proposed Rulemaking (NPRM), Air Contaminants.

REL - Recommended Exposure Limits (RELs) are issued by NIOSH to aid in controlling hazards in the workplace. These limits are generally expressed as 8 - or 10 - hour TWAs for a 40-hour workweek and/or ceiling levels with time limits ranging from instantaneous to 120 minutes. RELs are published in a variety of NIOSH documents.

RTECS - The Registry of Toxic Effects of Chemical Substances (RTECS) is a data base that lists an identification number, synonyms, Department of Transportation (DOT) hazard label information, EPA Toxic Substances Control Act (TSCA) information, OSHA and Mine Safety and Health Administration (MSHA) air exposure limits, and animal and human toxicologic data.

Substance - The term "substance" is used in the revised standard whereas "material" is used in the original. The meaning is the same.

TLV(R) - The Threshold Limit Value (TLV(R)) is a registered trademark for an exposure limit developed by the American Conference of Governmental Industrial Hygienists (ACGIH). A listing of TLVs may be found in the ACGIH's "Documentation of the Threshold Limit Values and Biological Exposure Indices for 1988-1989." TLVs may be stated as a time-weighted average (TLV(R)-TWA), a Short-Term Exposure Limit (TLV R-STEL), or a Threshold Limit Value Ceiling (TLV(R)-C). OSHA utilized the 1987-88 TLV's as a starting point for this rulemaking.

TSCA - The Toxic Substances Control Act (TSCA), administered by the Environmental Protection Agency (EPA), was passed by Congress to protect human health and the environment by requiring testing and necessary use restrictions to regulate the commerce of certain chemical substances.

WHO - The World Health Organization (WHO) is part of the United Nations. WHO's programs in occupational health include development of an occupational health information system, criteria for early detection of health impairment, and the development of internationally recommended health-based permissible exposure limits for occupational exposure to toxic substances.

I. Clearance of Information Collection Requirements

On March 31, 1983, the Office of Management and Budget (OMB) published a new 5 CFR Part 1320, implementing the information collection provisions of the Paperwork Reduction Act of 1980, 44 U.S.C. 3501 et seq. [48 FR 13666]. Part 1320, which became effective on April 30, 1983, sets forth procedures for agencies to follow in obtaining OMB clearance not later than the date of publication of the proposal in the Federal Register for collection of information requirements contained in proposed rules. It also requires agencies to include a statement in the notice of proposed rulemaking indicating that such information requirements have been submitted to OMB for review under Section 3504(h) of the Paperwork Reduction Act. The PELs update standard will create no additional recordkeeping requirements.

J. Maintaining Z-Tables Current

This Rulemaking was designed to overcome an 18 year gap between the 1971 adoption of the PELs in the 29 CFR 1910.1000 Z-Tables and the present. During this time period there were extensive changes in toxicology and health effects information, and the application of available control technologies. This resulted in the existing Z-Tables in 29 CFR 1910.1000 being out of date and incomplete. The new information demonstrated that some workers are not protected from exposure levels which represent a significant risk of material impairment of health.

Because of the magnitude of changes during this 18-year period, this Rulemaking has involved a large number of substances and interested parties. Consequently, OSHA designed this Rulemaking to use as a starting point the well established TLV's and REL's. The record during the public hearing was then used to determine the appropriate final PEL, consistent with OSHA's statutory obligations.

As a follow-up to this Rulemaking OSHA plans to develop and implement a methodology which will permit OSHA to keep the PELs current as time goes on. This point was raised by several commentors during the public hearing (ORC, TR 3-266; NAM, TR 3-338; G.E., TR 9-172), without specific detail regarding the best procedures OSHA should follow. OSHA agrees with these suggestions, and from the start of this Rulemaking has been considering how this objective can be attained. The program would be designed to be applicable to all sectors (general industry, maritime, construction, and agriculture). The methodology adopted will be designed to avoid duplicative efforts or gaps in coverage, to be protective of workers, and to be cost effective.

Updating the PELs in the Z-Tables on a regular basis insures that the latest evidence is considered as it becomes available, and that appropriate action to either reduce or increase permissible levels is initiated promptly. Commenters to this rulemaking cited several substances for which they believed significant new information would become available in the near future. OSHA intends to evaluate such evidence and, if appropriate, to initiate prompt action to revise the Z-Tables. OSHA may take such action on a single substance or on several substances. This continual, dynamic process of evaluation and revision, consistent with the priorities of the Agency will insure that the Z-Tables reflect the latest scientific evidence on the risks posed by the listed substances.

OSHA will use a variety of sources to determine which substances will be considered for updating. Information developed as a result of NIOSH studies and the annual updating of the TLVs will, of course, be used by OSHA.

At this time OSHA has not developed the details of the up-date process. It is anticipated that it will be planned with regularly scheduled update intervals, somewhere between 2 and 5 years. The process is expected to follow full 6(b) rulemaking procedures.

[54 FR 2332, Jan. 19, 1989; 54 FR 14909, April 13, 1989; 54 FR 28154, July 5, 1989]

Regulations (Preambles to Final Rules) - Table of Contents

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