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OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

Date: September 3, 2015

PC Code: 059201

DP Barcode: D428161

MEMORANDUM

SUBJECT: Response to Correspondence on Preliminary Review Findings for the Fish Short 

Term Reproduction Assay (OCSPP Guideline 890.1350) with Phosmet

TO: Joel Wolf, Chemical Review Manager

Tom Myers, Team Leader

Kevin Costello, Branch Chief

Risk Management and Implementation Branch II

Pesticide Re-evaluation Division (7505P)

Office of Pesticide Programs

FROM: Catherine Aubee, Senior Scientist

Environmental Risk Branch IV

Environmental Fate and Effects Division (7507P)

Office of Pesticide Programs

THROUGH: Jean Holmes, D.V.M., M.P.H., Branch Chief

Thomas Steeger, Ph.D., Senior Science Advisor

Environmental Risk Branch IV

Environmental Fate and Effects Division (7507P)

Office of Pesticide Programs

Phosmet was among 67 chemicals for which Tier 1 Endocrine Disruptor Screening Program 

(EDSP) test orders were issued in 2009 and 2010. A preliminary review of the submitted Tier 1 

data for phosmet identified deficiencies in three of the eleven studies which had potential to 

warrant repetition of the studies. Therefore, the Agency provided a courtesy notification of the 

preliminary findings to the test order recipient, Gowan Company, on October 30, 20141

.

 1 US EPA. 2014. EDSP-069201-54, Phosmet, Fish Short Term Reproduction, Male and Female Pubertals –

Response and Action Required. Email from R.P. Keigwin (c/o Tanja Crk, EPA) to E. Codrea (Gowan Company). 

October 30, 2014.
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On June 2, 2015, the Agency received a response from Gowan Company to the preliminary review 

findings for the Fish Short Term Reproduction Assay (OCSPP Guideline 890.1350) (MRID 

48673002)2

. The test order recipient’s response was assigned a unique MRID (49643801) 3 and 

DP Barcode (D428161). The response provided concurrence for a number of the Agency’s 

preliminary review findings, including generalized signs of overt toxicity in two treatment levels 

and the absence of certain effects at specific treatment levels. However, the test order recipient 

disagreed with the Agency’s preliminary findings regarding overt toxicity and decreased yolk 

synthesis in the low treatment level. The test order recipient also disagreed with the Agency’s 

preliminary findings regarding the impact of oocyte atresia in control females on the interpretation 

of study results. Finally, the test order recipient reported that its statistical analysis yielded 

conclusions that were different from the Agency’s preliminary conclusions for effects on survival 

and nuptial tubercle scores. Overall, Gowan Company contended that the study was conducted 

consistent with the available test guideline and that repetition of the study was not warranted.

The Agency has since completed its review of the Fish Short Term Reproduction Assay, which is

documented in a Data Evaluation Record (DER), indexed by MRID (48673002). The review 

concludes,

Although the mortality in the high treatment level, clinical signs of toxicity in the 

intermediate treatment level, and noteworthy rate of oocyte atresia in control females make 

the results difficult to interpret, when considered in context of other available Tier 1 EDSP 

data for phosmet, this study satisfies the EDSP Tier 1 Test Order requirement for a Fish 

Short-Term Reproduction Assay (OCSPP Guideline 890.1350).

The results of this final review are also captured in the publicly available, EDSP Tier 1 weight of 

evidence analysis for phosmet (US EPA 20154

).

 2 York, D.O. 2012. Phosmet – Short-term Reproduction Assay with the Fathead Minnow (Pimephales promelas) 

Following OPPTS 890.1350 and OECD 229 Guidelines. Unpublished study performed by Smithers Viscient. 

Wareham, MA. Lab Study No. 12791.6143. Gowan Company. Yuma, AZ. MRID 48673002. 3 E. Codrea. 2015. Response to Draft DER (DP Barcode D400673) on the Fish Short-Term Reproduction Assay 

with Phosmet (MRID 48673002). Report No. MEC-2015-5. Gowan Company. Yuma, AZ. MRID 49643801. 4 US EPA. 2015. EDSP: Weight of Evidence Analysis of Potential Interaction with the Estrogen, Androgen, or 

Thyroid Pathaways [sic]. Chemical: Phosmet. TXR No. 0057145. Office of Pesticide Programs and Office of 

Science Coordination and Policy. Washington, DC. Available online at 

http://www2.epa.gov/sites/production/files/2015-06/documents/phosmet-059201_2015-06-29_txr0057145.pdf.