Acute Exposure Guideline Levels Program

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A Brief History of the AEGLs Program

In the Bhopal, India disaster of 1984, approximately 2,000 residents living near a chemical plant were killed and 20,000 more suffered irreversible damage to their eyes and lungs following the accidental release of methyl isocyanate from a Union Carbide plant. The community did not know what chemicals were being used at the plant, how dangerous they were, and what steps to take in case of an emergency. This tragedy led to the need for governments around the world to identify hazardous substances and to assist local communities in emergency planning for chemical exposures.

In 1986, Congress wrote into law an emergency planning program under the Superfund Amendments and Reauthorization Act (SARA). SARA requires the U.S. Environmental Protection Agency (EPA) to identify extremely hazardous substances that coule be released into the air as a result of chemical spills, industrial explosions or fires, accidents during transport, or intentional releases due to actions of terrorists. In addition, states are required to have emergency response plans for such chemical releases developed at the local community level.

EPA and the Agency for Toxic Substances and Diseases Registry (ATSDR) requested that the National Research Council (NRC) through its Committee on Toxicology (COT) forumlate guidance on the use of procedures and methodologies to establish emergency exposure guideline levels for the general public. In 1993, the NRC published Guidelines for Developing Community Emergency Exposure Levels for Hazardous Substances. Those guidelines were updated in the 2001 report, Standing Operating Procedures for Developing Acute Exposure Guideline Levels for Hazardous Substances.

 In November 1995, the National Advisory Committee (NAC)—consisting of members from EPA, the Department of Defense, the Department of Energy, the Department of Transportation, other federal and state governments, the chemical industry, academia, and other organizations from the private sector— was established to identify, review, and interpret relevant scientific data and develop acute exposure guideline levels (AEGLs) for high-priority, acutely toxic chemicals. Using the NRC guidelines, the NAC has developed interim (preliminary) AEGL values for approximately 200 EHSs.

As the NAC began developing chemical-specific AEGL reports, EPA and US Department of Defense requested that the NRC independently review the preliminary AEGLs developed by the NAC.  In 1998, the NRC organized within its Committee on Toxicology the Committee on Acute Exposure Guideline Levels (AEGLs). The NRC committee reviews each preliminary AEGL report for scientific validity, completeness, and consistency with NRC guidelines. The NRC publishes final AEGLs values in a series of reports accessible through this website or The National Academies Press.

The US EPA maintains a chemical priority list for extremely hazardous substances and the interim AEGL values for these high-priority, acutely toxic chemicals initially developed by the NAC. Information on AEGL chemical priority lists and interim AEGL values can be found on the EPA AEGL Program website.