1.0  Introduction

The Occupational Safety and Health Administration (OSHA) is preparing to reopen the rulemaking record concerning the need to amend the Process Safety Management of Highly Hazardous Chemicals (PSM) standard (29 CFR 1910.119). The purpose of this action is to obtain comments, recommendations, data, and information from interested parties concerning the need for regulatory changes to ensure an acceptable level of safety for those workers using reactive chemicals. Information will also be sought concerning the costs and benefits associated with such changes and ways to minimize the impacts on small entities affected by any changes that may be made. Further, information will be sought concerning alternative regulatory and non-regulatory approaches for ensuring the safe handling of reactive chemicals during their manufacturing, processing, use, and/or storage.

On February 24, 1992, OSHA issued the final rule for PSM to establish safe procedures that were intended to minimize the likelihood of catastrophic releases of toxic, flammable, and combustible materials during their manufacturing, processing, use, and/or storage. The final PSM rulemaking also revised 29 CFR 1910.109, Explosives and Blasting Agents, to require that the manufacture of explosives and pyrotechnics be conducted in compliance with 29 CFR 1910.119.

The promulgation of the PSM standard was mandated under section 304 of the Clean Air Act Amendments of 1990, where the Secretary of Labor was required, in coordination with the Administrator of the Environmental Protection Agency (EPA), to issue a chemical process safety standard to prevent accidental releases of chemicals that pose a threat to employees. EPA, in addition, was directed under sections 301 and 112 of the amended Clean Air Act to issue regulations governing accidental release prevention, including publication of a list of regulated substances and thresholds and a risk management program (RMP) rule.

On June 20, 1996, EPA published in the Federal Register its final rule for risk management programs, as well as a partial list of regulated substances. Owners or operators of stationary sources that have more than a threshold quantity of a regulated substance must comply with the EPA RMP requirements no later than June 21, 1999, three years after the date on which a regulated substance is first listed by EPA, or on the date on which a regulated substance is first present in more than a threshold quantity in a process, whichever is later.

OSHA's provisions for the current PSM standard were scheduled for implementation along a five-year time line beginning May 26, 1992. OSHA's standard presents a listing of toxic and reactive chemicals and associated threshold quantities that determine the standard's applicability to industrial processes. In addition, processes are covered by the standard if they involve a flammable liquid or gas [as defined in 29 CFR 1910.1200(c)], on site, in one location in a quantity of 10,000 pounds or more, except for:

hydrocarbon fuels used solely for workplace consumption as a fuel, if such fuels are not part of a process containing another highly hazardous chemical covered by this standard; and

flammable liquids stored in atmospheric tanks or transferred which are kept below their normal boiling point without benefit of chilling or refrigeration.

The PSM standard does not apply to retail facilities, oil or gas well drilling or servicing operations, or normally unoccupied remote facilities.

The issue concerning the appropriate treatment of reactive chemicals within the context of process safety management has received closer attention in the Agency in the wake of a serious accident that took place at a U.S. chemical plant. On April 21, 1995, a catastrophic explosion and fire occurred at a facility owned by Napp Technologies, Inc., a specialty chemical plant in Lodi, N.J. The explosion and fire resulted in the deaths of five workers, injuries to eight workers, evacuation of 400 residents of the community, and destruction of the plant.

According to reports from the accident investigation, workers were mixing four chemicals -- sodium hydrosulfite, aluminum powder, potassium carbonate, and benzaldehyde -- prior to the explosion but were not fully informed of the hazards associated with the chemicals. Two of the chemicals, sodium hydrosulfite, a combustible solid, and aluminum powder, a combustible metal when in the form of finely divided particles, are listed in the chemical literature as water reactive and, along with the other two chemicals, also react explosively with heat. It is believed that the cause of the incident can be traced to either: 1) heat generated by the friction of blender blades running through the dry chemicals; or 2) water that leaked from a worn or defective drive shaft seal of a water-cooled agitator bar and that reached its way into the blending vessel containing the chemicals.

Appendix A of OSHA’s current PSM standard lists the toxic and reactive chemicals covered by that standard. The list is a compilation of highly hazardous chemicals that could cause a serious chemical accident as a result of their toxicity or reactivity and that, consequently, pose a potential danger to employees in a workplace. The reactive chemicals currently listed in Appendix A were drawn from chemicals listed in the National Fire Protection Association (NFPA) document, NFPA 49, "Hazardous Chemicals Data," and were cross-referenced and validated by means of other sources used by the Agency in the development of the Appendix A chemical list.

The hazard identification system used in NFPA 49 is based on the numerical identification system established in NFPA 704 (1990), "Standard System for the Identification of the Fire Hazards of Materials." The identification system in NFPA 704 rates the health, flammability, and reactivity of chemicals that may be present during fire fighting, spill control, or other emergencies and, according to the publication, "provides a simple, readily recognized, easily understood system of markings that provides a general idea of the hazards of a material and the severity of these hazards as they relate to handling, fire prevention, exposure and control."

The NFPA 704 reactivity (instability) hazard category addresses the susceptibility of materials to release energy. These materials are rated by degree of hazard based on the ease, rate, and quantity of energy release. The rating is from 0 to 4, with materials assigned the rating of 4 posing the greatest hazard. A rating of 4 includes materials that, in themselves, are readily capable of detonation or of explosive decomposition or reaction at normal temperatures and pressures. The number 3 rating includes materials that, in themselves, are capable of detonation or explosive decomposition or reaction but require a strong initiating source, must be heated under confinement before initiation, or react explosively with water. A rating of 2 is assigned to materials that readily undergo violent chemical change at elevated temperatures and pressures, react violently with water, or may form explosive mixtures with water. A rating of 1 is assigned to materials that, in themselves, are normally stable but which can become unstable at elevated temperatures and pressures. A rating of zero denotes materials that, in themselves, are normally stable, even under fire exposure conditions, and which are not reactive with water.

At the time of OSHA's earlier PSM rulemaking, the Agency chose to include only those chemicals having the two highest (that is, the two most dangerous) reactivity ratings under NFPA 49 because of the significant risk posed to workers. Chemicals rated 3 or 4 by NFPA 49 are those that are capable of undergoing detonation or explosive decomposition and generating the most severe blast or shock wave, thus causing fragmentation of piping, vessels, and containers, as well as serious damage to buildings and structures. OSHA included those chemicals designated 3 or 4 by NFPA 49 in Appendix A of the final PSM standard because the Clean Air Act Amendments of 1990 required the Agency to cover "highly reactive and explosive substances." All four of the chemicals involved in the Napp Technologies accident have reactivity ratings below 3 and were, therefore, excluded from the PSM Appendix A chemical list.

Because of the possibility that events similar to the Napp Technologies catastrophe may occur in the future, OSHA is considering the inclusion of additional selected reactive chemicals in the PSM Appendix A chemical list. Furthermore, in October 1995, OSHA was petitioned by the Union of Needletrades, Industrial and Textile Employees (UNITE), the United Steelworkers of America, the Oil, Chemical and Atomic Workers, the AFL-CIO, the International Association of Fire Fighters, and the International Chemical Workers Union to reopen the record under section 6(c) of the Act, which provides for the establishment of emergency temporary standards, and to undertake a revision of the PSM standard to comprehensively cover reactive chemicals.

At this time, OSHA has decided to exercise its rulemaking authority under section 6(b) of the Act by proceeding with an advance notice of proposed rulemaking (ANPRM) addressing reactive chemicals. Specifically, as described in a draft ANPRM (dated December 1, 1997), OSHA is considering adding all chemicals with an NFPA reactivity rating of 2 to the list of chemicals in Appendix A of the PSM standard. Moreover, other chemicals with a reactivity rating of 3 or 4 that are not in the Appendix A chemical list would also be added. Some of these chemicals were not included in the final rule's chemical list because it was erroneously assumed that they were covered as a flammable liquid or as an explosive; other chemicals were raised to a higher reactivity rating or were added to the rating by the NFPA. In the draft ANPRM, OSHA is also including all chemicals with a reactivity rating of 1, although the Agency states that it does not believe that these chemicals should be covered by the PSM standard, since the standard is intended to cover only highly hazardous chemicals. In total, 99 reactive chemicals have been identified in the draft ANPRM. When OSHA issues the ANPRM, the Agency plans to solicit comments on the question of the appropriate treatment of these reactive chemicals, both within the context of the PSM standard and through other alternative regulatory and non-regulatory approaches.

The purpose of this study is to provide technical and analytical support for the forthcoming OSHA PSM rulemaking and to assist in data gathering for a preliminary chemical and industry profile and economic analysis of the impacts of adding the 99 identified reactive chemicals to the scope of the PSM standard. More specifically, the tasks that were performed as part of this study include:

This draft interim report presents an overview of the PSM regulatory requirements (Chapter 2), an initial chemical and industry profile (Chapter 3), and an initial accident analysis (Chapter 4). References are contained in Chapter 5.

Appendix A provides a more detailed tabulation of the facilities in the Toxics Release Inventory (TRI) database expected to be impacted by the possible addition of 28 of the 99 identified reactive chemicals to the PSM standard (since only 28 of the 99 reactive chemicals are represented in the TRI database). Appendix B provides estimates of the number of plants and firms with fewer than 10 employees producing and/or using these same 28 reactive chemicals. Appendix C provides more detailed information about the accident data involving the 99 reactive chemicals.

It should be noted that the analyses and information presented in this report are based upon information from readily available, published secondary sources for each of the 99 reactive chemicals identified by OSHA in the draft ANPRM. However, additional data gathering and analyses are needed in order to expand upon this information, as well as provide best estimates of the number of affected plants and SBREFA-covered firms for all 99 chemicals combined. Similarly, additional data gathering and analyses may needed for a selected subset of the 99 reactive chemicals, where no accident data has been found, in order to develop an overall, comprehensive estimate of the number of fatalities and injuries involving the 99 reactive chemicals.