Regression method to estimate provisional TLV/WEEL-equivalents for non-carcinogens

There is a huge and changing number of chemicals in commerce for which work place exposure criteria have not been assigned. Assigning an exposure crite rion by an expert committee is resource-intensive-not soon available for th e large majority of chemicals in current use, In the absence of assigned cr iteria, we have provided a regression method to estimate a first-screen est imate of a 'TLV/WEEL-equivalent' inhalation time-weighted average exposure criterion for a pure chemical (or chemical group) from a measure of a non-s tochastic toxic exposure to elicit a chronic or sub-chronic health effect, known as a lowest observable adverse effect level (LOAEL) or a (highest) no observable adverse effect level (NOAEL), Results are presented for six dat a sets for which both a threshold limit value (TLV) or workplace environmen tal exposure level (WEEL) exposure criterion is presently assigned, and a L OAEL or NOAEL, measure of toxic health effect was available from the United States Environmental Protection Agency Integrated Risk Information System data base. The results can be applied as a first estimate of exposure to su bstances for which no TLV or WEEL (TLV/WEEL) exists, and also serve as a me chanism for identifying substances for potential re-evaluation of their exp osure limit, based on their relative position about the prediction models, (C) 2000 British Occupational Hygiene Society, Published by Elsevier Scienc e Ltd. All rights reserved.