The National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances (NAC/AEGL Committee) was established to develop scientifically credible short-term exposure limits for approximately 400 to 500 acutely toxic substances. These short-term exposure limits, referred to as acute exposure guideline levels, or AEGLs, are essential for emergency planning, response, and prevention of accidental releases of chemical substances. Further, it is important that the values developed be scientifically credible so that effective planning, response, and prevention can be accomplished.
To ensure scientific credibility, six major elements have been integrated into the AEGL development process. These elements are (1) adherence to the National Research Council (NRC) report Guidelines for Developing Community Emergency Exposure Levels for Hazardous Substances,1 with changes or additions described in this Standing Operating Procedures Manual (SOP manual); (2) consideration of other NRC guidelines for developing short-term exposure limits; (3) the use of scientifically acceptable processes and methodologies to ensure consistent and scientifically credible AEGL values; (4) a comprehensive search and review of relevant data and information from both published and unpublished sources; (5) the extensive evaluation of the data and the development of AEGLs by a committee of scientific and technical
experts from both the public and private sectors; and (6) a multi-tiered peer-review process culminating with final review and concurrence by the NRC.
With the recent participation of certain member-countries of the Organization for Economic Cooperation and Development (OECD), it is anticipated that the AEGL program will be expanded to include the international community. That should result in increased scientific and technical support, a broader scope of the review process, and an even greater assurance of scientifically credible AEGL values.
This SOP manual represents the NAC/AEGL Committee’s SOP Workgroup documentation of the procedures, methodologies, criteria, and other guidelines used by the NAC/AEGL Committee in the development of the AEGL values. The information contained herein is based on the guidance provided by the NRC (1993) guidelines report. This manual contains additions and further details and clarification of specific procedures, methodologies, criteria, and guidelines interpreted from the NRC guidelines that have been determined by the NAC/AEGL Committee to be a necessary supplement to the NRC guidelines. Procedures and methodologies included in this manual have been reviewed by the NAC/AEGL Committee and numerous OECD member countries and have received a review and concurrence by the NRC. New or modified procedures and methodologies that are developed and adopted by the NAC/AEGL Committee are classified as “proposed.” Such procedures and methodologies will be submitted from time to time to the NRC for review and concurrence. Upon concurrence by the NRC, they will be considered final and will serve as a supplement to the 1993 NRC guidelines and to this manual.
It is believed that adherence to a rigorous AEGL development process in general and the use of scientifically sound procedures and methodologies in particular will provide the most scientifically credible exposure limits that are reasonably possible to achieve. This document is considered a “living document” and the various procedures and methodologies, including those classified as “final,” are subject to change as deemed necessary by the NAC/AEGL Committee and the NRC Subcommittee on Acute Exposure Guideline Levels. As new data become available and new scientific procedures and methodologies become accepted by a majority of the relevant scientific community, the NAC/AEGL Committee, and the NRC, they will be integrated into the AEGL development process and the SOP manual. With this approach, both the scientific credibility of the AEGL values and the reduction in risk to the general population will be ensured.