Draft EDSP Guidance Document Available for Public Review and Comment

The U.S. Environmental Protection Agency (EPA) announced in a November 4, 2010, Federal Register notice the availability for public review and comment of a draft guidance document entitled, “Weight-of-Evidence Guidance Document: Evaluating Results of EDSP Tier 1 Screening to Identify Candidate Chemicals for Tier 2 Testing.” According to EPA, the purpose of the draft guidance document is “to set forth some general principles, criteria, and considerations EPA generally believes to be relevant using a weight-of-evidence (WoE) approach to evaluate data submitted as part of EPA’s…Endocrine Disruptor Screening Program (EDSP)” Tier 1 screening assays. The draft guidance is available online. Comments are due January 3, 2011.

In the Federal Register notice, EPA summarizes the EDSP as a “two-tiered paradigm for screening and testing chemicals with the potential to interact with the endocrine system.” EPA announced the final list of 67 chemicals selected for Tier 1 screening on April 15, 2009. Tier 1 screening is intended to identify substances that have the potential to interact with the estrogren, androgen, or thyroid hormonal systems. The purpose of Tier 2 testing is to identify further and characterize chemical-induced interactions with estrogren, androgen, or thyroid hormonal systems for risk assessment. EPA states that it expects the diversity in endocrine endpoints within and among the Tier 1 screening assays to provide corroborating information and support a WoE evaluation to yield a decision as to whether the chemical indentified in Tier 1 requires additional testing in Tier 2.

EPA’s final list of chemicals selected for Tier 1 screening includes:

Given EPA’s intent to use the WoE guidance to evaluate broadly Tier 1 screening data to determine whether additional Tier 2 testing is necessary, manufacturers of the chemicals selected for Tier 1 screening should review the draft guidance to ensure it will allow EPA to analyze Tier 1 screening data accurately to determine which chemicals will be selected for Tier 2.

Comment

The guidance itself notes that this approach is not meant to be any different in its application to the endocrine program than from other areas of scientific assessment where EPA utilizes a WoE approach. What is perhaps most interesting, is that this announcement acknowledges that the approach will be used to evaluate the “other scientifically relevant information (OSRI)” — which has been a controversial element of EPA’s endocrine testing program. Specifically, many interested parties have insisted that if EPA fairly and fully evaluates the body of existing data already developed and submitted to EPA, the need for the now-required “lower-tier” endocrine effect tests would not be justified. As a result, comments submitted on the current notice will allow another advocacy opportunity to advance the position that, in many cases, using a WoE approach in evaluating existing data will lead EPA to conclude that additional new testing is unnecessary.