UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

December 9, 2013 

MEMORANDUM: 

Subject: Captan- Anticipated Antimicrobial Risk Assessments and Data Needs for 

Registration Review 

PC Code: 081301 DP Barcode: 414055 

Decision No.: 478164 Registration No.: 400-583, 11678-01, 19713-258, 

42750-230, 66330-31 

Petition No.: NA Regulatory Action: Registration Review 

Risk Assess Type: Scoping Document Case No.: 0120 

TXRNo.:NA CAS No.: 133-06-02 

MRIDNo.:NA 40CFR: NA ~ 

From: 

Thru: 

To: 

Introduction 

Timothy C. Dole, P.''~ ,~ ~. PJ-t{ Industrial Hygienist 

Donna Randall, Senior Scientist ~~ ... ~ ~ 0 Q. rzlq /1 !> 

Risk Assessment and Science Sup~ta".IiSh RA S 

Antimicrobials Division (751 OP) 

Steven Weiss, Branch Chief L (? ..fn ~ {;j~ I d- }rt /13 

Laura 

Risk Assessment 

Parsons, Assistant 

and Science 

Branch 

Suppo 

ef ch (RASSB) _ ~ 

Antimicrobials Division (751 OP) 

Christina Scheltema, Chemical Review Manager 

Risk Management Implementation Branch 3 (RMIB 3) 

Pesticide Re-evaluation Division (7508P) 

Captan technical grade active ingredient is currently registered for formulation into end use 

products for use in the preservation of paints, plastics and adhesives to prevent degradation from 

fungi and bacteria. However, there are currently no registered antimicrobial end-use products 

containing captan as an active ingredient. EPA evaluated current agency science policies and 

risk assessment methods, updated toxicity and exposure data bases to determine the scope of 

work necessary for registration review ofthese technical labeled uses. While there are currently 

no registered end-use products containing captan, EPA anticipates that additional data are 

needed to evaluate the antimicrobial uses of captan during registration review. Furthermore, 

EPA anticipates that the registration review risk assessment will consider the potential 

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antimicrobial uses of captan. This memo describes the anticipated data requirements and risk 

assessments for the antimicrobial uses of captan. 

Human Health Data Requirements 

EPA anticipates that the following studies will be needed to assess human health risks for the 

antimicrobial uses of captan. 

• Indoor dermal and inhalation exposure studies (OCSPP 875.1200 and 875.1400), are 

anticipated as needed 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. 

• Outdoor dermal and inhalation exposure studies (OCSPP 875.1100 and 875.1300), are 

anticipated as needed to assess exposures from the airless sprayer application of captan 

treated paints. 

• An indoor surface residue study (OSCPP 875.2300) is anticipated as needed to assess 

incidental oral exposure from toddler object to mouth contact with household items and 

toys made from captan treated plastics. 

In addition to the exposure monitoring studies listed above, a 90 day inhalation toxicity study is 

typically required to assess inhalation exposures for material preservatives that are applied using 

open pour methods. Such a study is available for captan; however, it was previously not used to 

assess inhalation risks. EPA expects to evaluate the potential use of this study for inhalation risk 

assessment during registration review. 

Environmental Fate and Effects Data Requirements 

An ecological risk assessment for material preservative uses in paints, plastics and adhesives has 

not been conducted previously. Previous practice considered these indoor uses, with no 

environmental releases. These uses have been determined to potentially result in environmental 

releases, and under current practice risks from these environmental releases are assessed. The 

following scope of work discussion uses the review of the existing fate data base for captan and 

its major degradates discussed in the Registration Review Problem Formulation for Captan 

(Docket Number EPA-HQ-OPP-2013-0296-0003) for the conventional agricultural uses. The 

exposure scenarios associated with antimicrobial uses of captan are very different from 

conventional use, where captan is applied to crops or seed or seed pieces. In conventional uses, 

captan parent is present much longer, until it reaches water via runoff. EPA expects the captan 

degradate THPI to be the predominant residue associated with environmental exposures 

associated with antimicrobial uses of captan. For the plastic material preservative use, captan is 

expected to be released to water through industrial manufacturing processes and undergo 

wastewater treatment prior to discharge to surface waters. For this potential antimicrobial use of 

captan, AD expects captan to rapidly hydrolyze and metabolize in water to form THPI, prior to 

exposure of non-target organisms. Captan leaching during in-service use of paint (e.g., 

architectural paints) and adhesives is also expected to convert to THPI due to hydrolysis and 

metabolism prior to exposure of non-target organisms. 

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The Registration Review Problem Formulation for Captan (Docket Number EPA-HQ-OPP2013-0296-0003) outlined fate data needed to conduct risk assessments for conventional uses. It 

is anticipated that the assessment of antimicrobial uses will use the captan hydrolysis, photolysis 

(water and soil), aerobic and anaerobic soil metabolism, aerobic and anaerobic aquatic 

metabolism data, soil leaching-adsorption/desorption data and fish bioaccumulation data, and the 

TPHI aerobic soil and aquatic metabolism data. Several key environmental fate data for TPHI 

(i.e., hydrolysis [OCSPP 835-2120], aquatic photolysis [OCSPP 835-2240], and anaerobic 

aquatic metabolism [OCSPP 835-4400]) are not available for the aquatic exposure assessment. 

In the absence of these data, conservative assumptions will be made about the fate properties for 

THPI, including the use of predictive models to generate appropriate data. Additional 

anticipated fate data needed to conduct a risk assessment for the material preservative uses, 

where residuals may discharge to waste water treatment plants (WWTPs) includes: TPHI 

wastewater fate (biodegradation removal [OCSPP 835.3110, 835.3220, 835.3240, or 835.3280]) 

and effects (Activated Sludge Respiration Inhibition data). It is not anticipated that activated 

sludge sorption isotherm data is required because its log Kow is less than 3.0. To estimate 

concentrations in water from in-service uses of paints and plastics leaching data from these types 

of materials is anticipated as needed. The anticipated fate data gaps unique to the antimicrobial 

use patterns are listed in Table 1. 

The Registration Review Problem Formulation for Captan (Docket Number EPA-HQ-OPP2013-0296-0003) outlined ecological effects data needed to conduct risk assessments for 

conventional uses. It is anticipated that all antimicrobial uses will use TPHI acute freshwater 

fish and invertebrate data, chronic freshwater fish and invertebrate data, estuarine/marine 

mollusk data (more sensitive of the captan estuarine/marine species), vascular and non-vascular 

aquatic plant data, and rice vegetative vigor and seedling emergence data (paints and plastics 

uses only). In addition to the diatom study (850.4500) with captan identified as a data gap in 

the conventional use document, the following are anticipated ecological effect TPHI data gaps 

for antimicrobial uses: acute estuarine/marine mollusk data (OCSPP 850.1025 or 835.1055); 

acute estuarine/marine fish (OCSPP 850.1075) with a Silverside sp.; fish early life stage (OCSPP 

850.1400)-using the more acutely sensitive freshwater or estuarine/marine species; freshwater 

diatom (OCSPP 850.4500); and rice seedling emergence and vegetative vigor (OCSPP 850.4100 

and 850.4150) as listed in Table 1. No chronic freshwater invertebrate or chronic shrimp data is 

anticipated to be required because these were the least sensitive aquatic species to captan, and it 

is therefore unlikely they will be the risk drivers for TPHI. 

Data Requirement Summary 

The human health and environmental fate and effects data requirements associated with the 

antimicrobial uses of captan are summarized in Table 1. 

\ 

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Table 1 -Anticipated Data Needs for Antimicrobial Uses of Captan1 

Estimated 

Guideline Timeframe 

Numbe.-2 Study Title 

Test Material3 (Months from 

receipt of DCI)4 

Non-GDLN Special Leaching Study5

•

6 Treated article 24 

835.3110 Ready Biodegradability THPI 12 

835.3220 Porous Pot Test THPI 12 

835.3240 Simulation Test - Aerobic Sewage THPI 12 Treatment A. Activated Sludge Units 

Simulation Test to Assess the 

835.3280 Biodegradability of Chemicals Discharged THPI 12 

to Wastewater 

850.1025 or Acute Toxicity Estuarine/Marine THPI 12 850.1055 Organisms - Mollusk 

850.1075 Acute Toxicity Estuarine/Marine THPI 12 Organisms - Fish (preferred Silverside sp.) 

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

850.4100 Seedling Emergence - Tier II (rice)

6 THPI 12 

850.4150 Vegetative Vigor - Tier II (rice )

6 THPI 12 

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

850.3300/ Activated Sludge Respiration Inhibition TGAI, THPI 12 orOECD209 (ASRI/ 

875.1100 Dermal Outdoor Exposure8

•

10 TEP 36 

875.1200 Dermal Indoor Exposure9

•

10 TEP 36 

875.1300 Inhalation Outdoor Exposure·

8

•

10 TEP 36 

875.1400 Inhalation Indoor Exposure9

•

10 TEP 36 

875.2300 Indoor Surface Residues 11 Treated article 24 l . . The ant1c1pated data requrrements hsted m th1s table are for only the ant1m1crob1al uses of captan . 2 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/20 13-10 162.pdffor details. 3 TGAI - technical grade active ingredient; TEP -typical end-use product; THPI - degradate of captan; treated 

article - article containing captan as a material preservative. 4 Estimated timeframe allows time for review of protocols by EPA's Human Studies Review Board (HSRB) 

and /or the Institutional Review Board (IRB). 

5 Anticipated to be required for paints and plastics containing captan. 

6 The anticipated DCI will require the submission and EPA approval of a protocol prior to study initiation. 7 EPA published draft guidance under guideline OPPTS 850.6800 and has since published fmal guidance for this 

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

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

Respiration Inhibition Test (ASRI) will determine which of the four biodegradation tests is/are required. If the ASRI 

test EC50 is less than or equal to 20 mg!L, then either the (i)Biodegradation in Activated Sludge Study or (ii) 

Simulation Test- Aerobic Sewage Treatment: A. Activated Sludge Units or (iii) the Porous Pot Test is required. If 

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the ASRI test EC50 is greater than 20 mg!L, then the registrant must conduct either: (i) Ready Biodegradability or 

(ii) a) Biodegradation in Activated Sludge or b) Simulation Test- Aerobic Sewage Treatment: A. Activated Sludge 

Units or c) the Porous Pot Test. If the Ready Biodegradability study is conducted and passes, then no further testing 

is required. If, however, the antimicrobial fails the Ready Biodegradability study, then the a) Biodegradation in 

Activated Sludge or b) Simulation Test- Aerobic Sewage Treatment: A. Activated Sludge Units, or c) the Porous 

Pot study is required. 

8 Anticipated to be required to assess exposures from air less spray application of captan treated paints. 9 Anticipated to be 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. 

10 The anticipated DCI will require the submission and approval of a protocol by the HSRB prior to study initiation. 

11 Anticipated to be required to assess incidental oral exposures from toddlers mouthing plastic toys and household 

objects treated with or containing captan. 

Anticipated Risk Assessments 

EPA anticipates conducting occupational handler and post application assessments for the 

antimicrobial uses of captan. EPA anticipates conducting new residential risk assessments for 

use of treated paints and household plastics. 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. EPA anticipates conducting a risk assessment for the 

plastic application facility site, and in-service uses of plastics and paints (adhesives will be 

covered by these uses). 

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