EPA has issued final guidance on its weight-of-evidence approach that will be used to evaluate the results of chemical screening to determine which substances merit further study as potential endocrine disruptors. The approach will be used in EPA’s Endocrine Disruptor Screening Program (EDSP) to analyze the multitude of chemicals suspected of mimicking, blocking or altering the function of endocrine hormones—specifically estrogen, androgen and thyroid hormones.

According to the guidance, the approach takes into account “consideration of biological plausibility and coherence, strength and consistency of the body of evidence.” Under the approach, Tier 1 assays of the EDSP will be combined with other evidence from sources, such as peer-reviewed scientific studies, to determine what chemicals should be subjected to Tier 2 studies that could determine dose-response relationships and lead to appropriate regulations.