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INTRODUCTION

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

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

concerning the Preliminary Work Plan (PWP), which was posted in the captan registration 

review docket (EPA-HQ-OPP-2013-0296). Captan is a broad spectrum fungicide registered for 

use on fruit and nut trees, grapes, berries, vegetables, corn, soybeans, cereal grains, and forage 

crops. In addition, captan is registered for use as a seed and seed piece treatment, as a preplant 

root dip, and as a post-harvest fruit dip. Captan is also registered for use on ornamentals and 

turf. However, EPA’s 2004 Reregistration Eligibility Decision (RED) document for captan 

specifies that application to turf in residential sites, apartment buildings, daycare centers, 

playgrounds, sports fields or other residential areas is prohibited. Last, captan technical grade 

products are registered for formulation of fungicides and material preservatives for use in paints, 

plastics, and adhesives, which could be used in residential 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 captan. Last, there is a discussion of next steps.

UPDATES SINCE THE PWP WAS ISSUED

Focus Meeting. EPA is engaging registrants and other key stakeholders early in registration 

review to increase the process efficiencies. To this end, the Agency met with several captan 

technical registrants on September 23, 2013 to discuss captan use and usage, clarification of 

certain use patterns, and potential label amendments. Notes from the meeting may be found in 

the captan registration review docket, EPA-HQ-OPP-2013-0296.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

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

on June 26, 2013, and closed on August 26, 2013, the Agency received comments from the 

FIFRA Endangered Species Task Force (FESTF), the Center for Biological Diversity (CBD), the 

Physicians Committee for Responsible Medicine (PCRM), the Captan Task Force, the Northwest 

 

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http://www.epa.gov/oppsrrd1/registration_review/
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Horticultural Council, and the Antimicrobial Exposure Assessment Task Force II (AEATF II)

that primarily address the planned ecological and human health risk assessments and associated 

data requirements. In response to EPA’s request for comments on the specific topics of 

environmental justice, water quality concerns, and trade irritants, the CBD submitted comments 

on water quality and the Northwest Horticultural Council submitted comments on trade irritants. 

No comments were submitted on environmental justice. The CBD also submitted comments 

regarding the conduct of the planned endangered species assessment for captan. 

This section summarizes public comments that resulted in changes to the registration review data 

needs, risk assessments, or timeline, or comments that are of a broader regulatory nature. 

However, this section does not capture every comment made about the PWP nor all of the 

Agency’s responses. Public comments and EPA responses in their entirety are located in the 

docket, EPA-HQ-OPP-2013-0296. The Agency’s response to comments on the ecological risk 

assessment problem formulation and associated data needs are in the December 9, 2013

document, Response to Public Comments on the EFED Registration Review Problem 

Formulation for Captan. 

Comments submitted by the FESTF in EPA-HQ-OPP-2013-0296-0009.

Comment: Albaugh and Chemtura, two of the technical registrants for captan, are FESTF 

members and entitled to rely on the FESTF data. 

Response: The Agency thanks FESTF for its comment and will consider the FESTF data 

during the captan registration review. 

Comments submitted by the PCRM in EPA-HQ-OPP-2013-0296-0011.

Comment: A full life-cycle study indicated that fathead minnow (freshwater fish) growth and 

survival was affected at doses between 16.5 and 39.6 μg/L. The Agency likely has these data 

and we recommended considering whether it can be used in place of the early-life stage test.

Response: The data mentioned in this comment appear to be from an open literature study on 

captan, the parent compound. The PWP lists the fish early life stage study as an anticipated 

data requirement for the major degradate, THPI, not the captan parent. EPA has adequate 

fish data for captan, but not for THPI. This study is needed to support antimicrobial uses of 

captan, which involve releases to water, where captan will hydrolyze rapidly to THPI. The 

Agency is unable to use captan data in the assessment because captan is more toxic than 

TPHI, and an assessment based on captan data is likely to overestimate risk. 

Comments submitted by the Northwest Horticultural Council in EPA-HQ-OPP-2013-0296-

0013. 

The Northwest Horticultural Council (NHC) commented on trade irritants involving captan and 

the importance of captan to growers in the Pacific Northwest. NHC also provided specific use 

information for captan, which EPA will consider during the captan registration review. Specific 

comments and the Agency’s response are summarized below. 
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Comment: Indonesia and Saudi Arabia, who are among the top export markets for U.S. 

apples, do not have a maximum residue limit (MRL) for captan residues in apples. Saudi 

Arabia also has no MRL for captan in pears. China has no MRL for captan in cherries. 

These countries are top export markets for Northwest growers; therefore, we request that 

EPA harmonize MRLs for these countries with US tolerances. 

Response: During registration review, the Agency will work to minimize trade irritants and 

harmonize US tolerances with MRLs with its trading partners, to the extent feasible (and 

consistent with domestic law). To facilitate this, the Agency works with the USDA Foreign 

Agricultural Service and the United States Trade Representative to identify potential trade 

irritants. EPA is currently working with some of the countries identified by Northwest 

Horticultural Council to assist with the development of science-based MRLs.

Comment: Captan has long been used in the Pacific Northwest for control of diseases such 

as apple scab, bull’s eye rot in pome fruit, and Coryneum blight on stone fruit. These 

diseases are of significant economic concern. In addition, control of bull’s eye rot is 

especially critical for fruit exported to China, due to China’s strict import requirements 

involving this pathogen. 

Response: EPA will consider this information during the captan registration review. 

Comments submitted by the AEATF II in EPA-HQ-OPP-2013-0296-0014. 

Comment: The AEATF II, described in Pesticide Registration (PR) Notice 2009-1, is 

generating data that will satisfy the anticipated data requirements for worker and postapplication exposure. The Task Force submitted a description of its work, a copy of PR 

Notice information 2009-1, and a list of current AEATF II member companies. 

Response: EPA thanks AEATF for the submission of this information. Captan registrants 

may rely on the Task Force data or they may choose other options for submitting data, as

required, including generation and submission of their own data. 

PLANNED DATA NEEDS

Table 1 summarizes planned data needs for the conventional uses of captan in agriculture and on 

ornamentals. For additional discussion of the data needs, see the following documents: 

Registration Review Problem Formulation for Captan and Captan Human Health Risk Scoping 

Document in Support of Registration Review. 

Table 1: Planned Data Needs for the Conventional Uses of Captan in Registration Review

Guideline 

Number1 Study Title

Test Material2

Estimated 

Timeframe

(Months from 

receipt of DCI)

835.4100 Aerobic Soil Metabolism PAIRA or TGAI 24

835.4200 Anaerobic Soil Metabolism PAIRA or TGAI 24
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Table 1: Planned Data Needs for the Conventional Uses of Captan in Registration Review

Guideline 

Number1 Study Title

Test Material2

Estimated 

Timeframe

(Months from 

receipt of DCI)

835.4400 Anaerobic Aquatic Metabolism PAIRA or TGAI 24

850.6100

Environmental Chemistry Methods (ECM) 

and Associated Independent Laboratory 

Validation (ILV) for water

TGAI 12

850.2100 Avian Acute Oral Toxicity (upland game and 

passerine species) TGAI 12

850.2200 Avian Dietary Toxicity (upland game and 

waterfowl species) TGAI 24

850.4100 Seedling Emergence and Seedling Growth TEP 12

850.4150 Vegetative Vigor TEP 12

850.4500 Aquatic Plant Growth (aquatic non-vascular 

plant toxicity) TGAI 12

Non-GDLN

(Special Study) Honey Bee – Acute Oral Toxicity (Adult) TGAI 12

Non-GDLN

(Special Study) Honey Bee – Acute Oral Toxicity (Larvae) TGAI 12

870.7800 Immunotoxicity TGAI 12

875.2100 Turf Transferable Residue TEP 24

1 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

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PAIRA – Pure active ingredient radiolabeled; TGAI – technical grade active ingredient; TEP – typical end-use 

product

Table 2 summarizes the planned data needs to support the registration review of the 

antimicrobial uses of captan. At present, captan technical registrations allow formulation into 

end use products for in-can preservation of paints and stains, for preservation of plastics and 

adhesives, and for fungicides in paint to protect painted surfaces. For additional discussion of 

the data needs, see the December 9, 2013 memo, Captan- Anticipated Antimicrobial Risk 

Assessments and Data Needs for Registration Review. 

Table 2: Planned Data Needs for the Antimicrobial Uses of Captan in Registration Review

Guideline 

Number1 Study Title

Test Material2

Estimated 

Timeframe

(Months from 

receipt of DCI)

Non-GDLN

(Special Study) Special Leaching Study3 Treated article 24

835.3110 Ready Biodegradability THPI 12

835.3220 Porous Pot Test THPI 12
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Table 2: Planned Data Needs for the Antimicrobial Uses of Captan in Registration Review

Guideline 

Number1 Study Title

Test Material2

Estimated 

Timeframe

(Months from 

receipt of DCI)

835.3240 Simulation Test – Aerobic Sewage Treatment: A. 

Activated Sludge Units THPI 12

835.3280 Simulation Test to Assess the Biodegradability of 

Chemicals Discharged to Wastewater THPI 12

850.1025 or

850.1055

Acute Toxicity Estuarine/Marine Organisms –

Mollusk (Oyster Shell Deposition or EmbryoLarval Toxicity)THPI 12

850.1075 Acute Toxicity Estuarine/Marine Organisms –

Fish (preferred Silverside sp.) THPI 12

850.1400 Fish Early-Life Stage Toxicity Test (freshwater) THPI 12

850.4100 Seedling Emergence and Seedling Growth – Tier 

II (rice) THPI 12

850.4150 Vegetative Vigor – Tier II (rice) THPI 12

850.4500 Algal Toxicity – Tier II (freshwater diatom) THPI 12

850.3300 Activated Sludge Respiration Inhibition (ASRI)4 TGAI, THPI 12

875.1100 Dermal Outdoor Exposure5 TEP 36

875.1200 Dermal Indoor Exposure6 TEP 36

875.1300 Inhalation Outdoor Exposure5 TEP 36

875.1400 Inhalation Indoor Exposure6 TEP 36

875.2300 Indoor Surface Residues 7 Treated article 24

1 On May 8, 2013. EPA promulgated the Final Rule establishing Data Requirements for Antimicrobial Pesticides on 

May 8, 2013; the regulation becomes effective on July 8, 2013. See http://www.gpo.gov/fdsys/pkg/FR-2013-05-

08/pdf/2013-10162.pdffor details.

2 TGAI – technical grade active ingredient; TEP – typical end-use product; THPI – degradate of captan; treated 

article – article containing captan as a material preservative. 3 Required for paints and plastics containing captan.

4 EPA published draft guidance under guideline OPPTS 850.6800 and has since published final guidance for this 

under guideline OCSPP 850.3300: http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0154-

0021. OECD Test Guideline 209 can also be used as guidance for this study, available online at http://www.oecdilibrary.org/content/book/9789264070080-en. EPA expects that the results of the anticipated Activated Sludge 

Respiration Inhibition Test (ASRI) would determine which of the four biodegradation tests would be expected to be 

required. 

5 Required to assess exposures from airless spray application of captan treated paints.

6 Required to assess exposures from open pouring of wettable powder (WP) formulations during material 

preservation treatment of paints, plastics and adhesives and during the brush and roller application of captan-treated 

paints.

7 Required to assess incidental oral exposures from toddlers mouthing plastic toys and household objects treated 

with or containing captan. 

RISK ASSESSMENTS FOR REGISTRATION REVIEW

During registration review, the Agency anticipates the need to conduct a comprehensive

ecological risk assessment, including an endangered species assessment, for all registered uses of

captan. For human health, EPA anticipates the need to conduct revised dietary (drinking water)

and occupational risk assessments during registration review. EPA expects to re-evaluate the 90-
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day inhalation study for captan to determine the potential for use in inhalation risk assessment. 

If toxicological endpoints or points of departure are revised based on the data that are anticipated 

to be required for registration review, they will be considered in the new assessments, as well as 

any changes to the standard operating procedures or default exposure assumptions.

Table 3 summarizes the planned registration review risk assessments based on the EFED 

Problem Formulation, the HED Scoping Document, and the memo on Risk Assessment and Data 

Needs for antimicrobial uses of captan. 

Table 3: Planned Risk Assessments for the Captan 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 

Yes The ecological risk assessment will consider both 

captan parent and THPI, the major captan degradate.

EPA expects captan parent to be the predominant 

residue associated with conventional uses and THPI to 

be the predominant residue associated with 

antimicrobial uses, although there is also potential for 

exposure to captan under certain conditions.

Incidents Will check for 

updates

For a discussion of reported ecological incidents for 

captan, see page 22 of the Problem Formulation.

Human Health

Dietary

Food Yes Although the previous assessments showed no dietary 

risks of concern, EPA may update the dietary 

assessment to reflect the new carcinogenicity 

classification and any potential changes to toxicological 

points of departure (PODs), uncertainty factors, or 

percent crop treated.

Drinking water Yes EPA anticipates conducting a new drinking water 

assessment that considers both captan parent and its 

THPI degradate. The previous drinking water 

assessment considered THPI only.

Occupational

Handlers (mixers, loaders, 

applicators)

Yes EPA anticipates conducting new handler and postapplication assessments for ornamentals, turf, and the 

antimicrobial uses of captan. These assessments are 

expected to consider new SOPs and any new data. 

Post-application Yes

Residential

Handlers Yes EPA anticipates conducting new residential handler and 

post application assessments for ornamentals, turf, and 

antimicrobial uses (use of treated paints and plastics). 

These assessments are expected to consider new SOPs 

and any new data. 

Post-application Yes

Other
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Aggregate No Evaluates the combined risk from dietary and 

residential exposures.

Cumulative No Although captan and folpet share the common 

metabolite thiophosgene, its role in captan and folpet’s 

toxicity has not been determined because thiophosgene 

is transient and not easily measurable. Therefore, the 

EPA has not assumed that captan has a common 

mechanism of toxicity with folpet or any other 

substances.

Tolerances Yes EPA expects to update the captan tolerance expression 

in accordance with current policy. In addition, EPA 

anticipates modifying tolerance levels where feasible 

for international harmonization purposes. 

Incidents Will check for 

updates

For a discussion of reported human incidents for 

captan, see page 16 of the Scoping Document and the 

February 20, 2013 memo, Captan: Review of Human 

Incidents

TIMELINE

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

review in Table 4. The projected timeline has been updated since the PWP to reflect impacts of 

recent Agency actions shortening the timeframe between the FWP and DCI issuance and adding 

three months between posting draft risk assessments and proposed decisions. 

Table 4: Projected Captan Registration Review Timeline1

Activities Estimated Date

Opening the Docket

Open Docket and 60-day Public Comment Period 2013 – June (Completed) 

Close Public Comment Period 2013 – August (Completed) 

Case Development

Final Work Plan 2013 – December (Completed)

Issue DCI 2014 – Jan - March 

Data Submission22017 – Jan - March

60-day Public Comment Period for Draft Risk Assessments12018 – July- Sept

Registration Review Decision

60-day Public Comment Period for Proposed Registration Review 

Decision

2019 July - Sept

Registration Review Decision &Begin Post-Decision Follow-up 2020

Total (years) 7

1 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.

2 The time frame for data submission allows 3 years for human exposure monitoring studies, to allow for 

review by the Human Studies Review Board.
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NEXT STEPS

The Agency plans to require several environmental fate, ecological effects, and human health 

studies for captan through a Data Call-In Notice expected to be issued in early 2014.