2

INTRODUCTION

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

the registration review of EPTC. This work plan addresses public comments received concerning 

the Preliminary Work Plan (PWP), which was posted in the EPTC registration review docket 

(EPA-HQ-OPP-2012-0720). EPTC is a thiocarbamate herbicide registered for use against the 

growth of germinating annual weeds, especially grasses. There are a wide variety of registered 

food and non-food uses, and EPTC products are used primarily in agricultural and nonagricultural 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 timeline 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 EPTC. Lastly, there is a discussion of next steps.

UPDATES SINCE THE PWP WAS ISSUED

Since the PWP was issued in March there is one additional update to the list of planned data 

needs. Comments received did not result in a modification to the anticipated data needs or 

timeline detailed in the EPTC PWP. However, it has been determined that the avian oral toxicity 

study (850.2100) on the degradate is no longer required. The 850.2100 data requirement was 

required in the GDCI issued in conjunction with the 1999 EPTC RED. In 2001 the Agency 

waived the 850.2100 requirement (for the degradate) because the Agency determined that the 

degradate is less toxic and less persistent than the parent EPTC. With regards to the aerobic 

aquatic metabolism study (835.4300) that was also required in conjunction with the 1999 EPTC 

RED, this data requirement has been identified as past due and remains a data gap. The 

registrant has indicated that it has begun to make progress toward satisfying this requirement and

will submit the data in January 2015.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

During the 60-day public comment period on the EPTC Preliminary Work Plan, which opened 

on March 27, 2013 and closed on May 28, 2013, the Agency received one public comment. The 

comment was submitted by FIFRA Endangered Species Task Force (FESTF). The comment

 1 http://www.epa.gov/oppsrrd1/registration_review/
3

does not address the timeline described in the PWP or the planned ecological and human health 

risk assessments or data requirements. In the PWP, EPA also solicited comments on the specific 

topics of environmental justice, water quality concerns, and trade irritants, but no comments or 

information were received on those issues.

PLANNED DATA NEEDS

Table 1 below summarizes the planned data needs for EPTC based on the Registration Review –

Preliminary Problem Formulation for the Ecological Exposure and Risk Assessment for EPTC 

(PC Code 041401; DP Barcode 405959) and EPTC: Registration Review Scoping Document for 

Human Health Assessment. The planned data needs have not changed from that which was 

identified in the PWP.

Table 1: Planned Data Needs for the EPTC Registration Review

Guideline 

Number2 Study Title Test Material

Estimated 

Timeframe

(Months from 

receipt of DCI)

850.1350 Aquatic invertebrate life cycle (saltwater) TGAI 12

850.1400 Fish early-life stage toxicity (freshwater) TGAI 12

850.2100 Avian oral toxicity (passerine species) TGAI 12

850.4100 Terrestrial plant toxicity, seedling emergence2 TEP 12

850.4150 Terrestrial plant toxicity, vegetative vigor2 TEP 12

870.7800 Immunotoxicity TGAI 12

875.2100 Dislodgeable foliar residue and turf transferable 

residues TGAI 12-24

Outstanding Data Requirements

835.4300 Aerobic aquatic metabolism3 TGAI Due 01/2015

TGAI = technical grade active ingredient; TEP = typical end-use product

 2 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/#!documentDetail;D=EPA-HQ-OPPT-2009-0154-0028 3 The aerobic aquatic metabolism study was required via the GDCI issued in conjunction with the EPTC RED.
4

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 of EPTC. For human health, EPA will

conduct a revised occupational risk assessment during registration review. If toxicological 

endpoints or points of departure, or estimates of exposure, default assumptions or changes to 

standard operating procedures are revised based on new information or data that are required for 

registration review, then these will be considered in a new human health assessment. 

Table 2 below summarizes the planned registration review risk assessments based on the EFED 

Problem Formulation and HED Scoping Document and the planned assessments have not 

changed from what was included in the PWP.

Table 2: Planned Risk Assessments for the EPTC Registration Review

Type of Risk Assessment Conduct? Notes

Ecological and Environmental Fate

Comprehensive ecological 

(species to be assessed 

include terrestrial and 

aquatic organisms), 

including endangered 

species 

Y 

Incidents Y For a discussion of EPTC’s reported ecological 

incidents, see page 15 of the Problem Formulation.

Human Health

Dietary

Food N A revised risk assessment is not anticipated for the 

registration review of EPTC. 

Drinking water N A revised risk assessment is not anticipated for the 

registration review of EPTC. 

Occupational

Handlers (mixers, loaders, 

applicators)

Y A new occupational assessment (handler) is 

anticipated in order to incorporate updated 

assessment methodologies and data being required.

Post-application Y A new occupational assessment (post application) 

is anticipated in order to incorporate updated 

assessment methodologies and data being required

Residential

Handlers N No residential uses exist

Post-application N No residential uses exist

Other

Aggregate N The Agency does not anticipate conducting an 

aggregate risk assessment unless the dietary and 

drinking water is revised. 
5

Cumulative N The Agency has determined EPTC does not share a 

common mechanism of toxicity with other 

chemical substances. 

Tolerances Y Tolerance expressions will be evaluated and 

updated as necessary. Tolerances values are 

harmonized with MRLs.

Incidents Y For a discussion of EPTC’s reported human 

incidents, see page 8 of the Scoping Document.

TIMELINE

EPA has created the following estimated timeline for the completion of the EPTC registration

review in Table 3 below. The projected timeline has been updated since the PWP to reflect 

impacts of recent Agency actions shortening the timeframe between FWP and DCI issuance and 

adding a quarter in between posting of PRAs and proposed decisions. 

Table 3: Registration Review for EPTC – Projected Registration Review Timeline

Activities Estimated Date

Open Docket and 60-day Public Comment Period March 2013 - Completed

Close Public Comment May 2013 - Completed

Case Development

Final Work Plan Sept. 2013 - Completed

Issue DCI 2013: Oct. – Dec.

Data Submission 2015: Oct. – Dec.

60-day Public Comment Period for Draft Risk Assessments4 2017: April - June.

Registration Review Decision

60-day Public Comment Period for Proposed Registration Review 

Decision

2017: Oct. – Dec.

Registration Review Decision and Begin Post-Decision Follow-up 2019

Total (years) 6

NEXT STEPS

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

and human health studies for EPTC through a Data Call-In Notice, expected to be issued in

October – December 2013. 

 4 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.