Proper ConsiderationOf TSCA

Reform of the Toxic Substances Control Act is needed, but a guest editorial and the letter “Clarifying TSCA” by Howard S. Bender include misconceptions (C&EN, Aug. 12, page 3, and Sept. 9, page 9). Since TSCA was enacted, it has evolved and includes probably more than 60,000 compounds. Because many of the compounds listed have since been taken off the market, considerably less than the total number are currently being used and marketed.

Many of the compounds are of natural origin in addition to being produced synthetically. It is not true that there is no toxicity information for any of the compounds. For thousands of TSCA compounds, peer-reviewed toxicity data and information are available from numerous databases and reports. For example, “Sax’s Dangerous Properties of Industrial Materials” has information on some 28,000 TSCA compounds, and the Merck Index has data on some 18,000 of the compounds.

There should be some realistic time limit imposed on testing for TSCA-listed chemicals, especially those compounds for which no data exist. International cooperation can be achieved, for example, through Europe’s REACH (Registration, Evaluation, Authorisation & Restriction of Chemicals) program. Commercial mixtures should be tested but only after appropriate data are obtained for the components. Some materials, however, are produced only as mixtures. All testing methods including the cited high-throughput in vitro screening should be rigorously evaluated, and the latter should probably be used only as a “first pass” test. Priority in regulation should be based on environmental toxicity factors.

Proper consideration of what TSCA is and is not is essential to providing a win-win conclusion for all.

Robert E. Buntrock
Orono, Maine