Regulations (Preambles to Final Rules) - Table of Contents Regulations (Preambles to Final Rules) - Table of Contents
• Record Type: Occupational Exposure to 1,3-Butadiene
• Section: 3
• Title: Section 3 - III. Events Leading to the Final Standard

III. Events Leading to the Final Standard

The standard adopted for BD by OSHA in 1971 pursuant to Section 6(a) of the OSH Act, 29 U.S.C. 655 from an existing Walsh-Healey Federal Standard required employers to assure that employee exposure does not exceed 1,000 ppm determined as an 8-hour TWA (29 CFR 1910.1000, Table Z-1). The source of the Walsh-Healey Standard was the Threshold Limit Value (TLV) for BD developed in 1968 by the American Conference of Governmental Industrial Hygienists (ACGIH). This TLV was adopted by the ACGIH to prevent irritation and narcosis.

In 1983, the National Toxicology Program (NTP) released the results of an animal study indicating that BD causes cancer in rodents. (Ex. 20) Based on the strength of the results of this animal study, ACGIH in 1983 classified BD as an animal carcinogen and in 1984 recommended a new TLV of 10 ppm. (Ex. 2-4) Based on the same evidence, on February 9, 1984, the National Institute for Occupational Safety and Health (NIOSH) published a Current Intelligence Bulletin (CIB) recommending that BD be regarded as a potential occupational carcinogen, teratogen and a possible reproductive hazard. (Ex. 23-17) On January 5, 1984, OSHA published a Request for Information (RFI) jointly with the Environmental Protection Agency. (EPA) (49 FR 844) EPA also announced the initiation of a 180 day review under the authority of section 4(f) of the Toxic Substance Control Act (TSCA) (49 FR 845) to determine "whether to initiate appropriate action to prevent or reduce the risk from the chemical or to find that the risk is not unreasonable." Comments were to be submitted to OSHA by March 5, 1984. On April 4, 1984, OSHA extended the comment period until further notice. (49 FR 13389) Petitions for an Emergency Temporary Standard (ETS) of 1 ppm or less for workers' exposure to BD were submitted to OSHA on January 23, 1984, by the United Rubber, Cork, Linoleum and Plastic Workers of America (URW), the Oil, Chemical and Atomic Workers (OCAW), the International Chemical Workers Union (ICWU), and the American Federation of Labor and Congress of Industrial Organizations (AFL-CIO). (Ex. 6-4) On March 7, 1984, OSHA denied the petitions on the ground that the Agency was still evaluating the health data to determine whether regulatory action was appropriate.

Based on its 180-day review of BD, EPA published, on May 15, 1984, an Advance Notice of Proposed Rulemaking (ANPR) (49 FR 20524) to announce the initiation of a regulatory action by the EPA to determine and implement the most effective means of controlling exposures to the chemical BD under the TSCA. EPA was working with OSHA because available evidence indicated that exposure to BD occurs primarily within the workplace.

Information received in response to this ANPR was used by EPA to develop risk assessments. Subsequently, EPA identified BD as a probable human carcinogen (Group B2) according to EPA's classification of carcinogens, and concluded that current exposures during the manufacturing of BD and its processing into polymers presented an unreasonable risk of injury to human health. (Ex. 17-4) Additionally, EPA determined that the risks associated with exposure to BD may be reduced to a sufficient extent by action taken under the OSH Act. Following these findings, EPA, in accordance with section 9(a) of TSCA, on October 10, 1985 (50 FR 41393), referred BD to OSHA to give this Agency an opportunity to regulate the chemical under the OSH Act. EPA requested that OSHA determine whether the risks described in the EPA report may be prevented or reduced to a sufficient extent by action taken under the OSH Act and then if such a determination is made, OSHA issue an order declaring whether the manufacture and use of BD described in the EPA report present the risk therein described. EPA asked OSHA to respond within 180 days, by April 8, 1986. (50 FR 41393) On December 27, 1985, OSHA published a notice soliciting public comments on EPA's referral report. (50 FR 52952) Based on all the available information, OSHA, on April 11, 1986, responded to the EPA referral report by making a preliminary determination (50 FR 12526) that a revised OSHA standard limiting occupational exposure to BD could prevent or reduce the risk of exposure to a sufficient extent and that such risks had been accurately described by EPA in the report. On October 1, 1986, OSHA published an ANPR (51 FR 35003) to initiate a rulemaking within the meaning of section 9(a) of TSCA. The Agency requested that comments be submitted by December 30, 1986. Twenty-four comments, some of them containing new information, were received in response to the ANPR. (Ex. 28-1 to 28-24) Six additional comments were received after the deadline. (Ex. 29-1 to 29-6) OSHA reviewed the available data and conducted risk assessment, regulatory impact and flexibility analyses. These analyses demonstrate that the proposed standard was technologically and economically feasible and substantially reduced the significant risk of cancers and other adverse health effects.

On August 10, 1990, OSHA published its proposed rule to regulate occupational exposure to 1,3-butadiene. (55 FR 32736) Based on the Agency's review of studies of exposed animals and epidemiologic studies and taking into account technologic and economic feasibility considerations, OSHA proposed a permissible exposure limit (PEL) of 2 ppm as an 8-hour time-weighted average and a short term exposure limit (STEL) of 10 ppm for a 15 minute sampling period. Also included in the proposal was an "action level" of 1 ppm which triggered certain provisions of the standard such as medical surveillance and training.

OSHA convened public hearings in Washington, DC., on January 15-23, 1991, and in New Orleans, Louisiana, on February 20-21, 1991. The post-hearing period for the submission of briefs, arguments and summations was to end July 22, 1991, but was extended by the Administrative Law Judge to December 13, 1991, in order to give participants time to review new data on low-dose exposures submitted by NTP and a quantitative risk assessment done by NIOSH. The comment period closed February 10, 1992.

In the Fall of 1992, the International Agency for Research on Cancer (IARC) published the results of the Working Group on the Evaluation of Carcinogenic Risks to Humans, which reviewed the carcinogenic potential of BD and concluded that:

There is limited evidence for the carcinogenicity in humans of 1,3-butadiene * * * There is sufficient evidence for the carcinogenicity in experimental animals * * * (Ex. 125)

IARC stated that its overall evaluation led it to conclude that "1,3-butadiene is probably carcinogenic to humans (Group 2A)." (Ex. 125) To assist OSHA in issuing a final rule for BD, representatives of the major unions and industry groups involved in the production and use of BD submitted the outline of a voluntary agreement reached by the parties dated January 29, 1996, outlining provisions that they agreed upon and recommended be included in the final rule. The letter transmitting the agreement was signed by J.L. McGraw for the International Institute of Synthetic Rubber Producers (IISRP), Michael J. Wright for the United Steelworkers of America (USWA), and Michael Sprinker (CWU). The committee that worked on the issues also included Joseph Holtshouser of the Goodyear Tire and Rubber Company, Carolyn Phillips of the Shell Chemical Company, representing the Chemical Manufacturers Association, Robert Richmond of the Firestone Synthetic Rubber and Latex Company, and Louis Beliczky (formerly of the URW) and James L. Frederick of the SWA.

The agreement proposed a change in the permissible exposure limits, additional provisions for exposure monitoring, and an exposure goal program designed to reduce exposures below the action level. It also set forth other modifications to the scope, respiratory protection, communication of hazards, medical surveillance, and start-up dates sections of the final rule.

On March 8, 1996 OSHA published the labor/industry joint recommendations and re-opened the record for 30 days to allow the public to comment. (61 FR 9381) In response to requests from the parties to the agreement, the comment period was extended to April 26, 1996. (61 FR 15205) At the beginning of the comment period, OSHA placed in the rulemaking record an epidemiologic study of BD exposed workers by Delzell, et al. sponsored by IISRP, along with IARC volume 127 "Butadiene and Styrene Assessment of Health Hazards," a published paper by Santos-Burgoa, et al. entitled "Lymphohematopoietic Cancer in Styrene-Butadiene Polymerization Workers," and abstracts from a symposium entitled "Evaluation of Butadiene and Isoprene Health Risks." (Ex. 117-1; 117-2; 117-3; 117-4) The epidemiological study had also been submitted to the EPA in compliance with provisions of the Toxic Substances Control Act.

In response to the re-opening of the BD record, 18 sets of comments were received. The parties to the labor/industry agreement submitted a draft regulatory text which put their recommendations into specific requirements. The outline and the subsequent draft regulatory text are solely the work product of the negotiating committee. OSHA was neither a party to nor present at the negotiations.

While the responses to the record re-opening helped clarify the intent of the negotiating parties, the rationales behind several of the changes were not fully explained.

On September 16, 1996, Judge John M. Vittone, for Judge George C. Pierce who presided over the BD hearings, closed the record of the public hearing on the proposed standard for 1,3-butadiene and certified it to the Assistant Secretary of Labor. (Ex. 135)


Regulations (Preambles to Final Rules) - Table of Contents Regulations (Preambles to Final Rules) - Table of Contents