Jump to main content.


New AEGL Process (November 2011 to Present)

The AEGL program has been highly successful addressing all but 5 of the 329 chemicals listed in the AEGL Chemical Priority Lists. The accomplishment of this important milestone and budget constraints are the driving forces to instituting new changes to the AEGL developmental process. This resulted in redirecting funding and staff resources towards the finalization of AEGL values through the NAS Subcommittee. As a result, the AEGL/National Advisory Committee (AEGL/NAC Committee or AEGL Committee) was eliminated for future work of the AEGL program.

The new process focuses on finalizing interim AEGL chemicals through the NAS with the limited resources available. The following paragraphs describe the new changes to the development process of AEGLs.

Procedure To Address NAS comments That Would Not Result In Changes To AEGL Interim Values:

The AEGL program is not changing the approach to handle NAS comments that do not result in a change in AEGL values. Currently, the AEGL program receives technical support from a contractor that is responsible for making revisions to the AEGL technical support documents. As in the past, the contractor makes changes to the documents per the recommendations of the NAS Subcommittee and prepares the response to comments. The contract Project Officer (in this case the AEGL Program manager), reviews and approves the changes and response to comments. The revised technical support documents are submitted to the NAS for publication.

Procedure To Address NAS Comments That Would Result In Changes To AEGL Interim Values:

In the past, NAS recommendations resulting in changes to AEGL values were debated and approved by the AEGL Committee. In this process, the contractor responded to the NAS comments for a particular AEGL chemical and the response was taken to the AEGL Committee for their deliberation and approval. Under the new process, the AEGL Committee is no longer available and a new approach is presented below.

The new approach engages the federal stakeholders, but in a different way. Under the new procedures, the contractor addresses the NAS comments and revises the document as well as prepares a response to comments. Next, the response and the revised technical support document are sent to the federal stakeholders for a 2-week review. After consensus, the response and the revised technical support document are sent to the NAS. If consensus could not be reached, the differences are written and presented to the NAS for their resolution. Note that changes to the documents are not posted on the AEGL website until they are finalized by the NAS.

Old AEGL Process (1996 to October 2011)

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.
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. 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 theAEGL values. They include (1) draft AEGLs, (2) proposed AEGLs, (3) interim AEGLs, and (4) final AEGLs.

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.

Top of Page

Local Navigation

Jump to main content.