Chemical Exposures Working Group
The Chemical Exposures Working Group pre-dates SCAPA. It was originally established under the Department of Energy (DOE) Dose Assessment subcommittee (SCAPA’s predecessor) to make recommendations pertaining to the analysis of the hazards associated with chemicals.
Protection Action Criteria and Temporary Emergency Exposure Limits
Protection Action Criteria (PACs) define the concentration of airborne chemicals at which certain protective actions may be required. PACs are used by the DOE and National Nuclear Security Administration for emergency planning purposes and for selecting protective actions during operational emergencies involving chemical releases. PACs are based on:
- Acute Exposure Guideline Level (AEGL) values published by the U.S. Environmental Protection Agency (EPA);
- Emergency Response Planning Guideline (ERPG) values produced by the American Industrial Hygiene Association (AIHA);
- Temporary Emergency Exposure Limit (TEEL) values developed by SCAPA.
AEGLs and ERPGs are developed through a painstaking process that involves reviewing the primary scientific literature, proposing limits, having proposals subject to peer review by subject matter experts in the field, and revising the AEGLs and ERPGs accordingly. Although the specific processes for AEGL and ERPG value development differ significantly, both processes result in limits with a solid scientific foundation. To date, AEGLs and ERPGs have only been developed for a few hundred chemicals. In contrast, several thousand chemicals are stored or used at DOE facilities. An even a broader set of chemicals is stored or used by industry, academia, and government organizations in the United States and around the world. In response to this information gap, the DOE has supported the development of TEELs for chemicals that lack AEGL or ERPG values.
The current focus of the Chemical Exposures Working Group is to develop and maintain the PAC data set. This work involves:
- deriving TEELs for nominated chemicals
- periodically reviewing and updating existing TEEL values
- incorporating new and updated AEGL, ERPG, and TEEL values into the PAC data set
- enhancing the PAC/TEEL development methodology
- improving the functionality and ease-of-use of the PAC data set and development tools
- addressing technical questions from the PAC user community.
e TEEL Development Methodology
The methodology for the derivation of TEEL values uses hierarchies of existing and commonly available exposure limits. These include OSHA and ACGIH Short Term Exposure Limits and Ceiling Limits (PEL-STEL, TLV-STEL, PEL-C, and TLV-C), and NIOSH-developed Immediately Dangerous to Life or Health (IDLH) values, among others.
This hierarchy methodology was developed by members of the Chemical Exposure Working Group and other key contributors, was accepted by SCAPA after peer review, and was published in the September 1995 issue of the American Industrial Hygiene Association Journal of Occupational and Environmental Hygiene (member login required) (Alternative Guideline Limits for Chemicals without ERPGs, 56:919-925). More detailed information is provided in the TEELs Methods and Practice Handbook (pdf) (DOE-HDBK-1046-2008; August 2008). This document presents the framework used to develop PAC/TEEL values, the methodology followed, and sample derivations.
The TEEL methodology uses published human and animal acute toxicity data to derive ERPG-equivalent values. Statistical comparisons of ERPGs and human-equivalent acute toxicity data figure in this process. These enable expansion of the hierarchy of parameters used for derivation of TEEL-2 to include TCLO and TDLO values, and of TEEL-3 to include LC50, LCLO, LD50, and LDLO values, in order of availability. Toxicity data, which were extracted from SAX’s Dangerous Properties of Industrial Materials (Richard J. Lewis, Editor, Wiley-Interscience) and other sources (e.g., RTECS – ChemBank CD-ROM Databanks of Potentially Hazardous Chemicals, SilverPlatter Information, Inc., Norwood, MA), are used only if no concentration limit values exist. Human data are used first, followed by rat, mouse, and other species, adjusting animal data to human-equivalent doses using simple body weight, breathing rate and route-of-entry adjustments.
This expanded procedure has been used to derive TEELs for over three thousand chemicals for which exposure limits were required for emergency planning and safety analysis.
Want to know more about TEELs? Take a look at some further information!
Meeting Highlights
Working group meeting notes:
Additional Information
For further information on the DOE SCAPA Chemical Exposures Working Group, contact Doug Craig or Rocky Petrocchi.