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Process

AEGL Development Process (PDF) (1 pg, 16K, About PDF) - The development of AEGL values through the Federal Advisory AEGL Committee and stakeholder concept strives to accomplish the following process objectives:

  1. Development of scientifically valid AEGL values for use in chemical emergency planning, prevention and response programs.

  2. Comprehensive identification of published and unpublished information sources used to set AEGLs.

  3. Sharing resource burdens by stakeholder members.

  4. Adoption of consistent emergency planning both domestically and internationally.

  5. Transparency of program methods (Standard Operating Procedures or SOPs) and information through public participation at meetings and by commenting on Federal Register notices.

  6. Inclusion of National Academy of Sciences (NAS) peer review and final arbitration of AEGL values and methods.

AEGL Development and Peer-Review Process

 The process that has been established for the development of the AEGL values is the most comprehensive ever used for the determination of short-term exposure limits for acutely toxic chemicals. A summary of the overall process is presented in diagram form in Appendix B. The process consists of four basic stages in the development and status of the AEGLs, and they are identified according to the review level and concurrent status of the AEGL values. They include (1) draft AEGLs, (2) proposed AEGLs, (3) interim AEGLs, and (4) final AEGLs. The entire development process can be described by individually describing the four basic stages in the development of AEGL values.

Stage 1: Draft AEGLs

This first stage begins with a comprehensive search of the published scientific literature. Attempts are made to mobilize all relevant unpublished data through industry-trade associations and from individual companies in the private sector. A more detailed description of the published and unpublished sources of data and information utilized is provided in Section 2.3 of this document, which addresses search strategies. The data are evaluated by following the published NAS guidelines in 1993 and this SOP manual, and selected data are used as the basis for the derivation of the AEGL values and the supporting scientific rationale.

Data evaluation, data selection, and development of a technical support document (TSD) are all performed as a collaborative effort among the staff scientists at the organization drafting the TSDs, the chemical manager, and two chemical reviewers. This group is called the AEGL Development Team. Specific AEGL Committee members are assigned to a team for each chemical under review. Hence, a separate team comprising different committee members is formed for each chemical under review. The product of this effort is a TSD that contains draft AEGLs.

The draft TSD is subsequently circulated to all other AEGL Committee members for review and comment prior to a formal meeting of the committee. Revisions to the initial TSD and the draft AEGLs are made up to the time of the AEGL Committee meeting scheduled for formal presentation and discussion of the AEGL values and the documents. At the committee meeting, the committee deliberates and, if a quorum is present, attempts to reach a consensus or a two-thirds majority vote to elevate the draft AEGLs to "proposed" status. A quorum of the AEGL Committee is defined as 51% or more of the total AEGL Committee membership. If agreement cannot be reached, the committee conveys its issues and concerns to the AEGL Development Team and further work is conducted by this group. After completion of additional work, the chemical is resubmitted for consideration at a future meeting. If a consensus or a two-thirds majority vote of the committee cannot be achieved because of inadequate data, no AEGL values will be developed until adequate data become available.

Stage 2: Proposed AEGLs

 Once the AEGL Committee has reached a consensus or a two-thirds majority vote on the AEGL values and supporting rationale, they are referred to as "proposed" AEGLs and are published in the Federal Register for a 30-day review and comment period. Following publication, the committee reviews the public comments, addresses and resolves relevant issues, and seeks a consensus or a two-thirds majority vote of those present on the original or modified AEGL values and the accompanying scientific rationale.

Stage 3: Interim AEGLs

 Following resolution of relevant issues raised through public review and comment and subsequent approval of the committee, the AEGL values are classified as "interim." The interim AEGL status represents the best efforts of the AEGL Committee to establish exposure limits, and the values are available for use as deemed appropriate on an interim basis by federal and state regulatory agencies and the private sector. The interim AEGLs, the supporting scientific rationale, and the TSD, are subsequently presented to the NAS Subcommittee for its review and concurrence. If concurrence cannot be achieved, the NAS Subcommittee will submit its issues and concerns to the AEGL Committee for further work and resolution.

Stage 4: Final AEGLs

When concurrence by the NAS Subcommittee is achieved, the AEGL values are considered "final" and published by the NAS. Final AEGL values may be used on a permanent basis by all federal, state and local agencies, and private organizations. It is possible that new data will become available from time to time that challenges the scientific credibility of final AEGLs. If that occurs, the chemical will be resubmitted to the AEGL Committee and recycled through the review process.

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