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The 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 as 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!