Acute Exposure Guideline Levels
Quantitative guidelines for short-term inhalation exposure to hazardous chemicals.
Wikipedia / Wikimedia Commons
Acute Exposure Guideline Levels (AEGLs) are quantitative criteria that specify airborne concentrations of hazardous chemicals above which the general population, including susceptible individuals, may experience defined levels of adverse health effects from short-term exposure (up to eight hours). They are used in emergency preparedness and response to chemical spills, industrial disasters, and transportation accidents to guide evacuation zones, shelter-in-place orders, and safety precautions.
- field
- Toxicology and emergency response
- developed_by
- National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances (AEGL committee), with oversight by the U.S. Environmental Protection Agency and the National Academies
- first_meeting
- June 1996
- number_of_chemicals_discussed
- Over 300
- number_of_substances_with_AEGL_values_es
- At least 273 of 329 on the priority list
- exposure_durations
- 10 minutes, 30 minutes, 1 hour, 4 hours, 8 hours
- severity_levels
- AEGL-1 (discomfort/irritation), AEGL-2 (irreversible or serious effects), AEGL-3 (life-threatening or death)
Lore & Background
The AEGL committee's charter expired in October 2011, and its most recent meeting took place in April 2010. Despite the committee's work ending, the AEGL program at the EPA continues to function and collaborates with the National Academies to publish final AEGLs. The committee set the benchmark for a novel and successful approach to creating a single, superior scientific product needed by multiple federal, state, and private sector organizations.
Reader's Guide
AEGLs are important instruments for safeguarding public health during infrequent, unintentional releases of dangerous airborne compounds. They establish quantitative criteria for when anyone, including elderly, children, and those with health issues, may begin to experience negative health impacts from short-term exposure. Emergency planners, responders, and regulators worldwide use AEGLs to direct operations during chemical spills, industrial disasters, and transportation accidents, helping to designate evacuation zones, shelter-in-place orders, and safety precautions. The three severity levels (AEGL-1, AEGL-2, AEGL-3) and five exposure lengths allow for tailored responses. The U.S. Environmental Protection Agency and the National Academies use formal, peer-reviewed procedures for producing AEGLs, promoting scientific rigor and public transparency. AEGLs play an important role in risk assessments for fixed facilities and transportation carriers, assisting in the development of disaster preparedness plans, preventative methods, and real-time response. They provide a consistent language for communicating chemical risks during crises, assisting the public in determining when and what protective measures should be implemented.
Did You Know?
- AEGL-1 is the airborne concentration above which notable discomfort or irritation could be experienced, but effects are not disabling and are reversible once exposure stops.
- AEGL-2 is the airborne concentration above which irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape could be experienced.
- AEGL-3 is the airborne concentration above which life-threatening health effects or death could be experienced.
- The AEGL program was created after the 1984 methyl isocyanate leak in Bhopal, India, which killed over 2,000 people.
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