How did EPA select the list of regulated substances?

The list of regulated substances under the chemical accident prevention provisions is found in 40 CFR Part 68. How did EPA select the substances to be included in this list?

The chemical accident prevention provisions promulgated pursuant to Section 112(r) of the Clean Air Act (CAA) are designed to focus on chemicals that pose a significant hazard to the community in the event of an accidental release, and to prevent and minimize the consequences of such releases (59 FR 4479; January 31, 1994). EPA was required by CAA Section 112(r)(3) to promulgate an initial list of at least 100 regulated substances that are known to cause or may reasonably be anticipated to cause death, injury, or serious adverse effects to human health or the environment if accidentally released.

Congress required the inclusion of sixteen specific toxic substances on the initial list: chlorine, ammonia, anhydrous ammonia, methyl chloride, ethylene oxide, vinyl chloride, methyl isocyanate, hydrogen cyanide, hydrogen sulfide, toluene diisocyanate, phosgene, bromine, anhydrous hydrogen chloride, hydrogen fluoride, anhydrous sulfur dioxide, and sulfur trioxide (CAA Section 112(r)(3)). Additional toxic substances were included on the list based on toxicity, physical state, vapor pressure, production volume, and accident history.

Commercially produced flammable gases and volatile flammable liquids were listed on the basis of flash point and boiling point criteria used by the National Fire Protection Association for its highest flammability hazard ranking (59 FR 4480; January 31, 1994). For a complete description of the methodology and criteria used to select the substances, refer to the final rule (59 FR 4479; January 31, 1994), and proposed modifications (61 FR 16598, April 15, 1996).

On August 5, the Chemical Safety Information, Site Security and Fuels Regulatory Relief Act was signed into law (P.L. 106-40). Flammable fuels used as fuel or held for sale as fuel at a retail facility are no longer covered under the RMP program. However, flammable fuels used as a feedstock or held for sale as fuel at a wholesale facility are still covered.