New Endocrine Screening Approach May Be in Use in Two Years, Official Says

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The Environmental Protection Agency could start using computational toxicology tools as part of the Endocrine Disruptor Screening Program within the next two years and could move away from animal-based testing within five years, an EPA official said April 21.

The agency will use computational toxicology methods when it initially screens chemicals for their potential to interact with the endocrine system, Vicki Dellarco, senior science adviser in EPA's Office of Pesticide Programs, said at a meeting of the Pesticide Program Dialogue Committee in Arlington, Va.

“We could use it to inform us what pathways we should be looking at as part of Tier 1 screening,” Dellarco said.

Computational toxicology uses molecular biology, chemistry, and mathematical and advanced computer models to more effectively and efficiently rank chemicals based on risks. Dellarco described it as “being able to predict what may happen by understanding how it happens.”

Two-Tier Testing Used.

As part of a two-tiered screening approach, EPA first screens chemicals for their potential to interact with the endocrine system (Tier 1) and then tests chemicals for adverse effects on the endocrine system (Tier 2).

She said the move toward a complete “nonanimal approach” to endocrine disruptor testing would be more long-term. “It could be five years, it could be a little longer than five years,” she said.

The use of these methods in the endocrine program is a small part of an overall effort by EPA to use computational toxicology tools in screening.

EPA sought funds in its fiscal year 2012 budget request to start implementing the computational toxicology approach (35 CRR 328, 3/28/11).

Current System Will Not Be Scrapped.

The new approach to screening will not “scrap” the current testing system but would modernize it, Steven Bradbury, director of EPA's Office of Pesticide Programs, said.

Ray McAllister, senior director of regulatory policy for CropLife America, questioned why manufacturers would have to continue investing in the current endocrine disruptor testing program, in which they have spent “$100 million plus” thus far, if the program could be substantially improved.

“It's not that anything is wrong now,” Bradbury said. “It's just that science changes.”

By Avery Fellow


More information on EPA's endocrine disruptor screening program is available at




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