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PT Notes

OSHA RFI - Updating the List of Highly Hazardous Chemicals and Policy Change on Listed Chemicals Without Specific Concentrations

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On December 3, 2013, the U.S. Occupational Safety and Health Administration (OSHA) announced a request for information (RFI) seeking public comment on potential revisions to its Process Safety Management (PSM) standard. Multiple issues were addressed in the RFI.

One issue deals with updating the list of highly hazardous chemicals covered by the PSM standard and provided in Appendix A of the standard. The list has remained unchanged since OSHA promulgated the PSM standard in 1992.

OSHA has posed these questions on this issue in the RFI:

  1. What chemicals, if any, should OSHA add to the list of highly hazardous chemicals in Appendix A of the standard through rulemaking? Please provide any sources, data, or incident examples related to the hazards associated with the chemicals. What would be the economic impacts of adding the chemicals to the list? Are there any special circumstances involving small entities that OSHA should consider with respect to adding chemicals to the list?
  2. How often should OSHA update the list?
  3. Is there a method, other than periodically updating the list through rulemaking, that OSHA should use for periodically updating Appendix A when new hazards are discovered and as technology and advancements in chemical science evolve?

Another issue deals with changing enforcement policy for those chemicals listed in Appendix A without specific concentrations. Although Appendix A provides specific concentrations for 11 of its listed chemicals, the standard is silent on concentrations for the remaining 126 listed chemicals. For example, Appendix A lists hydrogen peroxide at concentrations of 52% by weight or greater, but a specific concentration is not provided for hydroxylamine.

OSHA has issued interpretation letters taking a variety of positions regarding coverage of chemicals that have no listed concentration. Under one such approach, OSHA considers PSM coverage to apply if threshold quantities of such chemicals are present at commercial grade which OSHA has interpreted as "a typical maximum concentration of the chemical that is commercially available and shipped." In a court case resulting from and explosion involving hydroxylamine, a U.S. District Court dismissed a criminal indictment based on inconsistencies in OSHA's statements regarding coverage of hydroxylamine. The Court pointed out that the PSM standard is ambiguous with respect to concentrations of Appendix A chemicals. It concluded that in light of a series of OSHA letters that were themselves inconsistent, no reasonable person in the defendant's position could determine how a chemical is covered by the standard.

In light of this finding, OSHA believes it is important to issue a clear and authoritative statement about PSM coverage of chemicals for which Appendix A does not include a specific concentration. With respect to the commercial grade approach, OSHA also realizes that it is difficult to determine the maximum commercial grade of many of the highly hazardous chemicals listed in Appendix A. In addition, the maximum commercial grade of a chemical may change over time due to technological innovation or changes in industry. Furthermore, even where the concentration of a PSM listed highly hazardous chemical falls below the correctly determined maximum commercial grade, the chemical may still present a hazard because substances in a mixture retain their original properties. For example, a solution of any concentration of hydroxylamine can form pure hydroxylamine crystals, which can rapidly decompose and cause fires or explosions.

An interpretative approach that is consistent with the regulatory language and that addresses this concern is the approach currently used by the U.S. Environmental Protection Agency (EPA) under the Risk Management Program (RMP) rule (40 CFR 68). The RMP rule provides a list of toxic substances similar to Appendix A in the PSM standard. However, EPA considers a mixture containing an RMP-listed substance to be covered if the concentration is greater than one percent and the calculated weight of the substance in the mixture is greater than the threshold quantity. With a few exceptions, this rule does not apply in cases where the operator can demonstrate that the partial pressure of the substance in the mixture is less than 10 mmHg.

OSHA invites comment on whether it should adopt the EPA's policy for RMP-listed substances as a simpler and more practical, consistent, and straightforward approach to addressing hazards associated with Appendix A chemicals that do not have listed concentrations.

OSHA has posed these questions on this issue in the RFI:

  1. Does your facility handle any chemicals excluded from PSM coverage on the basis that the concentration is below the "maximum commercial grade"? If so, what are these chemicals and concentrations, and would OSHA adopting EPA's policy for RMP-listed chemicals in mixtures as OSHA's enforcement policy for PSM-listed chemicals without specific concentrations result in PSM coverage of the chemicals in your facility?
  2. Please provide any data or information on workplace accidents, near misses, or other safety-related incidents involving highly hazardous chemicals excluded from PSM coverage on the basis that that the concentration was below the "maximum commercial grade."
  3. Please discuss any economic impacts that would result from OSHA adopting EPA's policy for RMP-listed chemicals in mixtures as OSHA's enforcement policy for PSM-listed chemicals without specific concentrations. Are there any special circumstances involving small entities that OSHA should consider with respect to this option?
  4. Is there a different enforcement policy that OSHA should use to protect workers from the hazards associated with the chemicals listed in Appendix A of the PSM standard without specific concentrations? Please discuss any economic impacts associated with your suggested enforcement policy. Are there any special circumstances involving small entities that OSHA should consider with respect to your suggested enforcement policy?

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Federal Register noticeĀ 

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