Reactives, highly hazardous

Toxic and reactive highly hazardous chemical which presents a potential for a catastrophic event at or above the threshold quantity 1,500 pounds OSHA 1998a (29 CFR 1910.119 Appendix A)... 

Application. The standard applies to a process that contains a threshold quantity or greater amount of a toxic or reactive highly hazardous chemicals as specified in the appendix to this chapter. Also, it applies to 10,000 pounds or greater amounts of flammable liquids and gases and to the process activity of manufacturing explosives and pyrotechnics. 

Chlorine is listed as a toxic and reactive highly hazardous chemical in Title 29 CFR Part 1910 of the U.S. Occupational Safety and Health Standards. The requirements for handling chlorine are well documented. Protective equipment is required to prevent inhalation and contact with eyes, skin, and clothing. Chlorine is often handled in confined areas to prevent accidental releases. These areas require continuous monitoring to detect chlorine leaks, air scrubbers. 

Explosibility and Fire Control. As in the case of many other reactive chemicals, the fire and explosion hazards of ethylene oxide are system-dependent. Each system should be evaluated for its particular hazards including start-up, shut-down, and failure modes. Storage of more than a threshold quantity of 5000 lb (- 2300 kg) of the material makes ethylene oxide subject to the provisions of OSHA 29 CER 1910 for "Highly Hazardous Chemicals." Table 15 summarizes relevant fire and explosion data for ethylene oxide, which are at standard temperature and pressure (STP) conditions except where otherwise noted. 

Table 1.9-1 List of Highly-Hazardous Chemicals, Toxics, and Reactives (Mandatoty)...

Highly Hazardous Chemical - Toxic, reactive, flammable, or explosive substances, as defined in Appendix A of 29 CFR 1910.119, "Process Safety Management of Highly Hazardous Chemicals."... 

OSHA. 1998a. Occupational Safety and Health Administration. Appendix A. List of highly hazardous chemicals, toxics, and reactives (mandatory). 29 CFR 1910.119. 

The information in this publication is applicable to many industrial facilities not covered by process safety regulations such as the OSHA PSM Standard and the Seveso II Directive. Many reactive chemicals are not listed as regulated materials, and chemical reactivity hazards include uncontrolled chemical reactions between materials not considered as highly hazardous, or under conditions not typically encountered in storage and shipping. 

Bhopal and a series of other major incidents underscored the need for increased attention to process safety management OSHA began to develop a standard that would incorporate these principles. A proposed standard was published in 1990. Additionally, the Clean Air Act Amendments (CAAA) of 1990 required OSHA to promulgate a standard to protect employees from the hazards associated with releases of highly hazardous chemicals, including reactive chemicals. 

The OSHA PSM Standard lists 137 highly hazardous chemi-cals-only 38 of which are considered highly reactive based on NFPA instability ratings of "3" or "4."... 

What criteria could be used in the context of process safety regulations to classify chemical mixtures as highly hazardous due to chemical reactivity ... 

CSB found significant gaps in OSHA process safety regulations designed to protect workers from highly hazardous chemicals, including reactive hazards. OSHA standards cover the hazards of some classes of substances, such as flammable and combustible liquids however, no OSHA standard specifically addresses reactive hazards. 

There are OSHA standards designed to protect employees from acute chemical hazards resulting lfom reactive incidents-including fires, explosions, and toxic releases. The Hazard Communication Standard (29 CFR 1910.1200) requires chemical manufacturers to evaluate chemicals produced or handled in their workplace and to communicate the hazards associated with the products they produce via labels and MSDSs. The standard also requires all employers to provide information to employees about the hazardous chemicals to which they could be exposed. The PSM Standard (29 CFR 1910.119) requires employers to prevent or minimize the consequences of catastrophic releases of highly hazardous chemicals, including highly reactive chemicals. 

OSHA relied on several established lists-including the New Jersey Toxic Catastrophe Prevention Act (TCPA), the Delaware Extremely Hazardous Substances Risk Management Act, the European Communities Seveso Directive (82/501/EEC), and NFPA Hazardous Chemicals Data (NFPA 49)-to develop its list of highly hazardous chemicals. OSHA chose to list the chemicals classified as reactive category 3 or 4 in NFPA 49 (1975 edition). 

Another requirement of the PSM Standard is that the employer conduct process hazard analysis, which OSHA defines as an organized and systematic effort to identify and analyze the significance of potential hazards associated with the processing or handling of highly hazardous chemicals. The analysis must identify the hazards of the process and necessary safeguards however, the standard does not explicitly define requirements for addressing reactive hazards. 

Addition of NFPA category 1 and 2 reactives to the list of highly hazardous chemicals. 

OSHA PSM-covered facilities are required to investigate each incident which resulted in, or could reasonably have resulted in a catastrophic release of a highly hazardous chemical in the workplace (29 CFR 1910.119 [m] [1]). At the conclusion of an incident investigation, the company is required to prepare a report on the factors that contributed to the incident. At present, OSHA does not require submittal of these incident reports. However, mandatory submission of the reports would increase available data and thus improve the capability of identifying or tracking reactive incidents. 

The company maintains a list of chemicals that are considered to be highly hazardous based on such characteristics as flash point (less than 100°F), self reactivity, water reactivity, boiling point, and toxicity. 

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