Docket Number EP A-HQ-OPP-20 12-0413 

www.regulations.gov 

Triphenyltin Hydroxide (TPTH) Final Work Plan 

Registration Review 

Case Number 99 

May2013 

Approved by: ~~Cl.<..d-- p ~I~ 

Date: 

Richard P. Keigwin, Jr. 

Director 

Pesticide Re-evaluation Division 
INTRODUCTION 

This is the Environmental Protection Agency's (EPA or the Agency) Final Work Plan (FWP) for 

the registration review of triphenyltin hydroxide (TPTH), also known as fentin hydroxide. This 

work plan addresses public comments received concerning the Preliminary Work Plan (PWP), 

which was posted in the TPTH registration review docket (EPA-HQ-OPP-2012-0413). TPTH is 

a non-systemic foliar fungicide registered for use to control early and late blight on potatoe.s; 

Colorado potato beetle and leaf spot on sugar beets; and scab, brown leaf spot and other diseases 

on pecans. In addition to its fungicidal activity, TPTH exhibits anti-feeding properties for 

surface-feeding in.sects. There are no registered residential uses, and TPTH products are used 

primarily in agricultural areas. 

The Agency is implementing the registration review program pursuant to Section 3(g) of the 

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and will review each registered 

pesticide every 15 years to determine whether it continues to meet the FIFRA standard for 

registration. Changes in science, public policy, and pesticide use practices occur over time. The 

registration review program is intended to make sure that, as the ability to assess risk evolves and 

as policies and practices change, all registered pesticides continue to meet the statutory standard. 

The public phase of registration review begins when the initial docket is opened for each case. 

Information on this program is provided on the Agency's website. 1 

The FWP begins with any updates since the PWP was issued. Next is a summary of substantive 

comments received during the public comment period for the PWP concerning anticipated data 

needs, expected risk assessments, or the estimated time line identified in the PWP, and a 

summary of the Agency's responses to those comments. This section is followed by registration 

review planned data needs, risk assessments expected to be conducted, and the projected 

registration review timeline for TPTH. Lastly, there is a discussion of next steps. 

UPDATES SINCE THE PWP WAS ISSUED 

Based on comments provided by the Physicians' Committee for Responsible Medicine after the 

PWP was issued, and considering submitted immunotoxicity studies in rats and mice as well as 

data available in the published literature, the Agency has determined that the anticipated data 

requirement in the PWP for an immunotoxicity study (GLN 870.7800) is no longer required. As 

a result, in the TPTH FWP, the immunotoxicity study has been removed from the list of 

anticipated data requirements in Table 1. 

SUMMARY OF COMMENTS AND AGENCY RESPONSES 

During the 60-day public comment period on the TPTH PWP, which opened on December 12, 

2012 and closed on February 12, 2013, the Agency received two comments. Comments were 

submitted by the FIFRA Endangered Species Task Force (FESTF) and the Physicians Committee 

for Responsible Medicine (PCRM). The comments do not address the timeline described in the 

PWP, but they do address the planned ecological and human health risk assessments and data 

requirements. In the PWP, EPA also solicited comments on the specific topics of environmental 

1 http :I lwww .epa.gov I opp~rrd 1/registration _review I 

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justice, water quality concerns, and trade irritants, but no comments or information were received 

on those issues. 

Summarized below are public comments that resulted in changes to the anticipated registration 

review data needs, or are of a broader regulatory nature. Public comments and EPA responses in 

their entirety are located in the docket, EPA-HQ-OPP-2012-0413. Agency responses related to 

the anticipated data needs are in the EPA Health Effects Division (HED) memo titled TPTH 

(I'riphenyltin Hydroxide). Response to Comments; Recommendation for Immunotoxicity Study 

Waiver. 

Comment submitted by FESTF in EP A-HQ-OPP-2012-0413-0009: 

1. Comment: "The technical registrants, as identified on the fact sheet included in the 

Registration Review Summary, include Bayer CropScience and Nufarm Americas, Inc., 

which are FESTF members and are entitled to rely on FESTF data. " 

Response: The Agency thanks FESTF for the comment and will consider this information 

during registration review. 

Comment submitted by PCRM in EPA-HQ-OPP-2012-0413-0010: 

2. Comment: "Regarding the Immunotoxicity data request, we found four studies that may be 

useful in the risk assessment process. We encourage the Agency to waive the request for a 

new Immunotoxicity study for TPTH based on the data provided by these studies. " 

Response: The Agency has determined that the requirement for an immunotoxicity study has 

been satisfied based on submitted immunotoxicity studies in mice and rats as well as the data 

available in the published literature. 

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PLANNED DATA NEEDS 

Table 1 below summarizes the planned data needs for TPTH based on the Registration Review: 

Preliminary Problem Formulation for Environmental Fate, Ecological Risk, Endangered 

Species, and Human Health Drinking Water Exposure Assessments for Triphenyltin Hydroxide 

(I'PTH), the TPTH (I'riphenyltin Hydroxide). Health Effects Division (HED) Scoping Document 

for Registration Review, and the TPTH (I'riphenyltin Hydroxide). Response to Comments; 

Recommendation for Jmmunotoxicity Study Waiver. The table has been updated since the PWP 

to reflect public comments which resulted in changes to the data needs. 

Table 1: Planned Data Needs for the TPTH Registration Review 

Estimated Guideline Timeframe 

Number Study Title 

Test Material (Months from (GLN) receipt of DCI) 

835.4100 Aerobic Soil Metabolism2 TGAior 24 PAIRA 

850.1300 Aquatic Invertebrate Life Cycle (freshwater) TGAI 12 

850.1350 Aquatic Invertebrate Life Cycle (saltwater) TGAI 12 

850.1400 Fish Early-Life Stage (saltwater) TGAI 12 

850.2100 Avian oral toxicity (passerine species) TGAI 12 

Environmental Chemistry Methods and Associated 

850.6100 Independent Laboratory Validation for soil and 

water3 

TGAI 12 

The study listed below was previously required through a generic data call-in (GDCI-083601-17847), 

issued in November 1999, received in January 2001, and is currently under EPA review. This study is 

listed in this document as background; it will NOT be included in the anticipated Registration Review 

DCI as it is already required through the earlier DCI. 

835.1230 

(listed as Adsorption/Desorption TGAI or Under EPA 163-1 in (Batch Equilibrium) 4 PAIRA review 1999 

GDCI) 

TGAI = techmcal grade act1ve mgred1ent; TEP = typical end-use product; PAIRA = pure act1ve mgred1ent 

radiolabeled; 

2 Since acceptable aerobic soil metabolism data on two soils out of the four soils required in GLN 835.4100 have been submitted 

to EPA previously, acceptable data on two more soils are required. Soils should be representative of soils on which TPTH use is 

expected to occur. If a foreign soil is used, it must be demonstrated to be comparable to a U.S. soil. Registrants should consult 

the guideline 835.4100 for further guidance. 3 On June 27, 2012, EPA announced certain revisions in harmonized guideline series 850- Ecological Effects Tests - including 

renumbering and other designations or changes for some guideline studies. See "Final Test Guidelines; OCSPP 850 Series; 

Notice of Availability" 77 FR 38282, June 27, 2012. http://www.regulations.gov/#!documentDetaii:D=EPA-HO-OPPT-2009-

0154-0028 

4 The 1999 GDCI stated the following: "Adsorption/desorption studies are required in order for the Agency to perform 

environmental fate assessments. The submitted adsorption/desorption study was a thin-layer chromatography (TLC) study, which 

does not provide Kds, which are necessary for fate assessments. A batch study is required." 

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RISK ASSESSMENTS FOR REGISTRATION REVIEW 

During registration review, the Agency will conduct a comprehensive ecological risk assessment, 

including an endangered species assessment, for all uses ofTPTH. For human health, EPA will 

conduct revised dietary and occupational risk assessments during registration review. If 

toxicological endpoints or points of ~eparture are revised based on the data that are required for 

registration review, they will be considered in the new assessments, as will any changes to the 

standard operating procedures or default exposure assumptions. 

Table 2 below summarizes the planned registration r~view risk assessments based on the EFED 

Problem Formulation and HED Scoping Document. The planned assessments have not changed 

from what was included in the PWP. 

Table 2: Planned Risk Assessments for the TPTH Registration Review 

- Type of Risk Assessment Conduct? Notes 

Eeoio&iiilfiict·'EnvirC»iimentai Fate .· • ·. 

Comprehensive ecological y The Agency plans to evaluate risks to nontarget 

(species to be assessed terrestrial and aquatic organisms, including Federallyinclude terrestrial and aquatic listed threatened and/or endangered species. 

organisms), including 

endangered species 

Incidents Will check for For a discussion of reported ecological incidents for 

updates TPTH, see page 14 of the Problem Formulation. 

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Dietary 

Food y The Agency anticipates conducting a revised dietary 

risk assessment. 

Drinking water y The Agency plans to conduct a drinking water 

exposure assessment for TPTH. 

Occupational 

Handlers (mixers, loaders, y The Agency anticipates conducting a revised 

applicators) occupational exposure and risk assessment during 

registration review. 

Post-application y The Agency anticipates conducting a revised 

assessment for post-application exposures from 

TPTH. The need for a bystander inhalation risk 

assessment for TPTH also will be examined. 

Residential 

Handlers, post-application, TPTH is not registered for use in residential settings. 

incidental oral, and N Therefore, a residential exposure assessment is not 

recreational required. 

Other 

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Aggregate y Evaluates the combined risk from dietary and 

residential exposures. Since there are .no residential 

uses of TPTH, the aggregate risk estimate will be 

equivalent to the dietary risk estimate. 

Cumulative N TPTH is not a member of a cumulative group and no 

cumulative risk assessment is planned. 

Tolerances y The tolerance expression will be revised to ensure that 

it appropriately covers the metabolites and degradates 

of TPTH and that it specifies the residues to be 

measured for each commodity. 

Incidents Will check for For a discussion of reported human incidents for 

updates TPTH, see page 8 of the Scoping Document and the 

TPTH (Fentin Hydroxide): Review of Human 

Incidents. 

TIME LINE 

EPA has created the following estimated time line for the completion of the TPTH registration 

review in Table 3 below. The projected timeline has not changed since the PWP. 

Table 3: Registration Review for TPTH- Projected Registration Review Timeline 

Activities Estimated Date 

Opening the Docket 

Open Docket and Open 60-day Public Comment Period for PWP and December 2012 -

Supporting Documents ComQleted 

Close Public Comment - February 2013 -

Completed 

Case Development . Issue Final Work Plan May2013-

Completed 

Issue DCI 2014-Jan- March 

Data Submission 2016-Jan- March 

Open 60-day Public Comment Period for Draft Risk Assessments;) 2017- July- Sept. 

Registration Review Decision 

Open 60-day Public Comment Period for Proposed Registration Review 2018-Jan- March 

Decision 

Issue Registration Review Decision and Begin Post-Decision Follow-up 2018 

Total (years) 6 

5 The regulations governing Registration Review generally require the Agency to provide a public comment period 

of at least 30 calendar days for draft risk assessments; see 40 CFR Part 155.53(c). For conventional pesticides, the 

Agency plans to provide a 60 calendar day public comment period generally for draft risk assessments. 

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NEXT STEPS 

As noted previously, the Agency plans to require several environmental fate and ecological 

effects studies for TPTH through a Data Call-In Notice, expected to be issued in 2014. 

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