There are currently three AEGLs: AEGL-1, AEGL-2, and AEGL-3. AEGL-1 is the airborne concentration of a substance above which it is predicted that the general population could experience notable discomfort, irritation, or certain asymptomatic nonsensory effects. These effects are not disabling and are transient and reversible once exposure is stopped. AEGL-2 is the airborne concentration (of a substance above which it is predicted that the general population could experience irreversible, long-lasting adverse health effects or an impaired ability to escape. AEGL-3 is the airborne concentration of a substance above which it is predicted that the general population could experience life threatening health effects or death.
On April 22-24 2013, the NRC-established Committee on Acute Exposure Guideline Levels 2013 met to review AEGL documents approved by the NAC. The committee members were selected for their expertise in toxicology, medicine, industrial hygiene, biostatistics, and risk assessment. Twenty-second Interim Report of the Committee on Acute Exposure Guideline Levels presents a review of AEGLs for various chemicals including acrylonitrile, halogen fluorides, tellurium hexafluoride, and thionyl chloride.