UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460

MEMORANDUM
Date: May 7, 2013 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

SUBJECT: TPTH (Triphenyltin Hydroxide). Response to Comments; Recommendation for Immunotoxicity Study Waiver PC Code: 083601 Decision No.: 476725 Petition No.: NA Risk Assessment Type: NA TXR No.: 0056654 MRIDNo.:NA DP Barcode: 4l0327 Registration No.: NA Regulatory Action: Registration Review Case No.: 99 CAS No.: 76-87-9 40 CFR: 180.236
FROM: Mohsen Sahafeyan, Risk Assessor

# ,./~**~c---:.:--z--** __ Nancy McCarroll, Toxicologist

### ~C1Q..**~¥-** Risk Assessment Branch VI (RAB VI) Health Effects Division (HED, 7509P) Office ofPesticide Programs THROUGH: Felecia Fort, Branch Chief RABVI;HED TO: Katherine St. Clair, Chemical Review Manager Risk Management & Implementation Branch IV Pesticide Re-evaluation Division (PRD) (7508P) Office ofPesticide Programs
Conclusion: The HED concluded that the immunotoxicity study is not required for TPTHbased on the HASPOC conclusion that the requirement for this study has been satisfied with consideration of submitted immunotoxicity studies in mice and rats, as well as the data available in the published literature. Additionally, although TPTH has shown evidence for immunotoxicity, the Points of Departures used for overall risk assessment will be protective ofpotential immunotoxicity from exposure ofTPTH.Background: PRD notified HED ofa conunent received from the Physicians Conunittee for Responsible Medicine (PCRM) during conunent period (letter dated 2/12/2013) for TPTH registration review docket. PCRM Comment: "Regarding the Immunotoxicitydatarequest, we found four studies that maybe useful in the risk assessment process. We encourage the Agency to waive the request for a new Immunotoxicity study for TPTH based onthe dataprovided bythese studies." The following studies were cited.

• Vos, JG, Krajnc, E I. (1983). Develop Toxicol Environ Sci 11:229-240 at http:/ /toxnet.nlm.nih.gov · • WorldHealth Organization/International Programme on Chemical Safety (1999). Concise International Chemical Assessment DocumentNo. 13 Triphenyltin compounds. 4-5 athttp:// toxnet.nlm.nih.gov • Sullivan, J B, Jr. Krieger, GR. (1992)
. Hazardous Materials Toxicology-Clinical Principles ofEnvironmental Health at http://toxnet.nlm.nih.gov • Vos, J Get al. (1984)
. Effects oftriphenyltinhydroxide onthe inunune system ofthe rat. Toxicology: 29-4 325-336 at http://www.unboubdmedicine.com HED Response: On April25, 2013 the RiskAssessment Branch (RAB) VIrequested the Hazard and Science Policy Council (HASPOC) to discuss the need for an inununotoxicity study (Guideline series 870.7800) to support the existing uses ofTPTH. In addition to the literature studies submitted bythe PCRM, the HASPOC also considered two special TPTH inununotoxicity studies in rats and mice submitted to the Agency (MRID 41518200). The HASPOC (TXRNo.0056652) concluded that the requirement for inununotoxicity study has been satisfied based on the submitted immunotoxicity studies in mice and rats as well as the dataavailable in the published literature
. Additionally, although TPTH has shownevidence for inununotoxicity, the Points ofDepartures used for overall risk assessment will be protective ofpotential inununotoxicity from exposure to TPTH.

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