Description
Extremely hazardous substances (EHSs) can be released accidentally as a result of chemical spills, industrial explosions, fire, or accidents involving railroad cars or trucks transporting EHSs, or they can be released intentionally through terrorist activities. These substances can also be released by improper storage or handling. Workers and residents in communities surrounding industrial facilities where EHSs are manufactured, used, or stored and in communities along the nation's railways and highways are potentially at risk of being exposed to airborne EHSs during accidental or intentional releases.
As part of its efforts to develop acute exposure guideline levels for EHSs, the Environmental Protection Agency (EPA) and the Agency for Toxic Substances and Disease Registry (ATSDR) in 1991 requested that the National Research Council (NRC) develop guidelines for establishing such levels. In response to that request, the NRC published Guidelines for Developing Community Emergency Exposure Levels for Hazardous Substances in 1993. Subsequently, Standing Operating Procedures for Developing Acute Exposure Guideline Levels for Hazardous Substances was published in 2001. It provided updated procedures, methods, and other guidelines used by the National Advisory Committee (NAC) on Acute Exposure Guideline Levels (AEGLs) in considering acute adverse health effects to develop AEGL values.
Using both these reports, the NAC--consisting of members from the EPA, the Department of Defense (DOD), the Department of Energy (DOE), the Department of Transportation (DOT), other federal and state governments, the chemical industry, academia, and other organizations from the private sector--developed AEGLS for approximately 270 EHSs. Twenty-First Interim Report of the Committee on Acute Exposure Guideline Levels: Part A summarizes the committee's conclusions and recommendations for improving AEGL documents for several chemicals and chemical classes.
