UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

MEMORANDUM 

Jan 13, 2016 

SUBJECT: Thiram: Response to Comments on the Human Health Risk Scoping Document in 

Support of Registration Review 

PC Code: 07980 I DP Barcode: 430994 

Decision No.: 512617 Registration No.: NA 

Petition No.: A Regulatory Action: Registration Review 

Risk Assessment Type: Single Chemical Aggregate Case No.: 0122 

TXR No.: NA CAS No.: 137-26-8 

MRID No.: NA 40 CFR: § 180. 132 

FROM: Dennis McNeilly, Chemist/Risk Assessor P--- fotf '-' ~~ Kelly O'Rourke, Occupational/Residential Exp sure Assessor ~ fr(,(? Yh~~ Hannah 

Risk Assessment 

Pope-Varsalona

Branch 

, 

IV 

PhD, Toxicologist · 

l_ 

~ 

· - Health Effects Division (7509P) -

THROUGH: Thurston Morton, Senior Chemist /,tJftfr 

Risk Assessment Branch 4 

Health Effects Division (7509P) /I Al./J / ,J--

}"{,1issa Reave;:1~hD. Branch Chief <fY !\/&{/ 

Risk Assessment Branch 4, HED (7s09P) 

TO: Wilhelmena Livingston, PMT 60 

Risk Management and Implementation Branch 4 

Pesticide Reevaluation Division (7508P) 

Attached is Health Effects Division's (HED) response to comments submitted on the human 

health risk assessment status update for thiram conducted as part of the Registration Review 

process (D42781 l, 8/20/15). A summary of submitted comments followed by HED's response 

is provided below. 

Comment: The Thiram Task Force recognizes the need for many of the studies listed as 

Anticipated Data Needs for the Thiram Registration Review. however, there are a few 

studies that the Thiram Task Force would like the Agency to reconsider. A turf transferable 

residue study is not needed. 

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Dislodgeable foliar residue studies in strawberries have been conducted for thiram. Using 

conservative default values for turf transferable residues (TTR) in the human health risk 

assessment, post-application dermal margins of exposure (MO Es) ranged from 850 to 1000 for 

children 6 to <1 I years old, children 11 to <16 years old, and adults. These MOEs are well above 

the level of concern of I 00. It was further noted that the estimated residential turf post 

application exposure for golfing on treated golf courses using default TTR was not minimal in 

comparison to the level of concern as the calculated MOE was not greater than 10 times higher 

than the level of concern. The TTF request that the Agency reconsider this data requirement as 

the lowest MOE was 850. 

Although not 10-fold higher, this MOE approaches I 0-fold greater than the level of concern 

based on conservative default values. Conducting this expensive study would not be expected to 

significantly add to an already conservative risk assessment and the requirement for the TTF 

study should be reconsidered. 

HED Response: At the registrant's request, EPA has reconsidered the requirement for the turf 

transferrable residue study and has confirmed that the data are necessary. In accordance with the 

updated (2007) Part 158 data requirements of the 40 CFR, turf transferrable residue (TTR) data 

are required for all turf uses that could result in post-application exposure to treated turf. The 

guidance for waiving these data was developed in consultation with the Office of General 

Council, with consideration given to the conservative nature of the standard/default residue 

transfer values. The waiver criterion, requiring that MOEs are 10 times greater than the level of 

concern (LOC), was based on the data used to develop these standard/default residue transfer 

values. In the case of thiram, the LOC is 100; therefore, all MO Es would need to be 1000 or 

above in order for the TTR data waiver to be granted. The assessment of thiram's turf use (golf 

course) yields an MOE of 850 for Children 6 to <11 years old, which does not meet the criterion; 

therefore, the waiver may not be granted. 

Comment: An error correction is requested, Taminco was granted an import tolerance for thiram 

on or in avocado in June 2015. Pages 4, 9 and 11 should indicate that this was an import 

tolerance. As written, it appears that a tolerance was granted for avocado applications in the US. 

HED Response: HED concurs that it could be clarified that the tolerances for avocado is for 

imported avocadoes only, i.e., no US registrations. 

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