Regulatory Developments

Draft EDSP Guidance Document Available for Public Review and Comment

November 4, 2010 PRINT

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(EPA) announced in a November 4, 2010, Federal Register notice the availability for public review and comment of a draft guidance document entitled, "Weight-of-Evidence Guidance Document: Evaluating Results of EDSP Tier 1 Screening to Identify Candidate Chemicals for Tier 2 Testing." According to EPA, the purpose of the draft guidance document is "to set forth some general principles, criteria, and considerations EPA generally believes to be relevant using a weight-of-evidence (WoE) approach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 The draft guidance is available online.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:

Chemical Name CAS Number
2,4-D 94757
4,7-Methano-1H-isoindole-1, 3(2H)-dione,2-(2-ethylhexyl)-3a,4,7,7a-tetrahydro- 113484
Abamectin 71751412
Acephate 30560191
Acetone 67641
Atrazine 1912249
Benfluralin 1861401
Bifenthrin 82657043
Butyl benzyl phthalate 85687
Captan 133062
Carbamothioic acid, dipropyl-, S-ethyl ester 759944
Carbaryl 63252
Carbofuran 1563662
Chlorothalonil 1897456
Chlorpyrifos 2921882
Cyfluthrin 68359375
Cypermethrin 52315078
DCPA (or chlorthal-dimethyl) 1861321
Diazinon 333415
Dibutyl phthalate 84742
Dichlobenil 1194656
Dicofol 115322
Diethyl phthalate 84662
Dimethoate 60515
Dimethyl phthalate 131113
Di-sec-octyl phthalate 117817
Disulfoton 298044
Endosulfan 115297
Esfenvalerate 66230044
Ethoprop 13194484
Fenbutatin oxide 13356086
Flutolanil 66332965
Folpet 133073
Gardona (cis-isomer) 22248799
Glyphosate 1071836
Imidacloprid 138261413
Iprodione 36734197
Isophorone 78591
Linuron 330552
Malathion 121755
Metalaxyl 57837191
Methamidophos 10265926
Methidathion 950378
Methomyl 16752775
Methyl ethyl ketone 78933
Methyl parathion 298000
Metolachlor 51218452
Metribuzin 21087649
Myclobutanil 88671890
Norflurazon 27314132
o-Phenylphenol 90437
Oxamyl 23135220
Permethrin 52645531
Phosmet 732116
Piperonyl butoxide 51036
Propachlor 1918167
Propargite 2312358
Propiconazole 60207901
Propyzamide 23950585
Pyridine, 2-(1-methyl-2-(4- phenoxyphenoxy)ethoxy)- 95737681
Quintozene 82688
Resmethrin 10453868
Simazine 122349
Tebuconazole 107534963
Toluene 108883
Triadimefon 43121433
Trifluralin 1582098

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.


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.

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