Pyrethrins Reclassified in EPA Health Assessment Review

WASHINGTON, D.C. — The Cancer Assessment Review Committee of the U.S. Environmental Protection Agency (EPA) has issued its finding that pyrethrins, which are naturally occurring insecticides found in the flowers of chrysanthemum species grown in Africa and Australia, are unlikely to cause cancer in humans at doses to which people are likely to be exposed.

“This is an important conclusion and a positive finding,” said David Carlson, McLaughlin Gormley King (MGK) Company, Technical Chair of the Pyrethrin Steering Committee/Joint Venture.

EPA had relied on lifetime feeding studies in rats, a standard procedure for assessing potential human health effects, in an earlier evaluation. In these studies, rats are fed much higher doses than humans would ever likely ingest, even in high exposure situations. Based on these studies, in the past the EPA concluded that there might be human health effects under specific, although unlikely, circumstances. It reversed this position, however, based on new scientific evidence showing that the mode of action by which pyrethrins affect rats is not applicable to humans at the dose levels at which humans would be exposed.