United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508C)
EPA-738-F99-015
September 1999
R.E.D. FACTS
CAPTAN
Pesticide
Reregistration
Use Profile
All pesticides sold or distributed in the United States must
be registered by EPA, based on scientific studies showing that they
can be used without posing unreasonable risks to people or the
environment. Because of advances in scientific knowledge, the law
requires that pesticides which were first registered before November
1, 1984, be reregistered to ensure that they meet today's more
stringent standards.
In evaluating pesticides for reregistration, EPA obtains and
reviews a complete set of studies from pesticide producers,
describing the human health and environmental effects of each
pesticide. To implement provisions of the Food Quality Protection
Act of 1996 (FQPA), EPA considers the special sensitivity of infants
and children to pesticides, as well as aggregate exposure of the
public to pesticide residues from all sources, and the cumulative
effects of pesticides and other compounds with common
mechanisms of toxicity. The Agency develops any mitigation
measures or regulatory controls needed to effectively reduce each
pesticide's risks. EPA then reregisters pesticides that meet the
safety standard of the FQPA and can be used without posing
unreasonable risks to human health or the environment.
When a pesticide is eligible for reregistration, EPA explains the
basis for its decision in a Reregistration Eligibility Decision (RED)
document. This fact sheet summarizes the information in the RED
document for reregistration case 0120, captan.
Captan is a fungicide used to control diseases on orchard
crops, seed treatments, ornamentals, lawns and turf, and is also
used as an in-can preservative in adhesives and paint. Formulations
include dust, emulsifiable concentrate, flowable concentrate, water
dispersible granules, wettable powder, and a variety of others.
Captan is applied by sprayers, chemigation equipment, power
duster, liquid seed treater, paintbrush, tank-type sprayers, and other
application methods. Captan is also applied as a post-harvest dip to
apples, cherries and pears.
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Regulatory
History
Human Health
Assessment
Captan was first registered as a pesticide in the U.S. in 1951.
EPA published the August 18, 1980 Notice of Rebuttable
Presumption Against Reregistration (RPAR) because it had
determined that captan exceeded certain risk criteria. The RPAR
Notice was triggered by the Agency's receipt of data demonstrating
that captan could induce oncogenic effects in experimental mammals
(mice and rats).
The Agency issued a Registration Standard for captan in March
1986. The captan Registration Standard identified the data gaps
required to be satisfied in order to continue the existing registration.
A 1988 Data Call-In Notice required the submission of additional
toxicity data.
EPA published the Position Document (PD4) "Captan; Intent To
Cancel Registrations; Conclusion of Special Review" (54FR8116) on
February 24, 1989. This notice announced the conclusion of EPA's
Special Review and risk/benefit analysis of captan registrations.
EPA evaluated additional data received and issues raised received
during the Special Review process and decided to allow the
continued registration of the following uses: all non-food uses, seed
treatments, and certain food uses listed in the PD4 (almonds, apples,
apricots, blackberries, blueberries, celery plant-beds, cherries,
dewberries, eggplant plant-beds, grapes, green onions, lettuce,
mangoes, nectarines, peaches, post-harvest pears, pepper plant-
beds, pimento plant-beds, plums/prunes, raspberries, spinach plant-
beds, strawberries, taro and tomato plant-beds). The Notice
canceled all other uses.
Currently, 158 captan products are registered, of which nine are
manufacturing-use products. Two technical registrants, Tomen Agro,
Inc. and Makhteshim-Agan of North America, are members of the
Captan Stewardship Task Force.
Toxicity
The human health risk assessment evaluated toxicological and
exposure data to develop dietary, drinking water, residential,
aggregate and occupational exposure analyses, and to assess the
adequacy of existing tolerances. Because the available studies
demonstrated no indication of increased sensitivity of animals to in
utero or postnatal exposure to captan and the database is complete,
the Agency determined that there is no evidence of special sensitivity
to infants and children. Therefore, the FQPA Safety Factor was
removed (reduced to 1X) for captan and the RfD equals the PAD.
The developmental endpoint in rabbits, with a NOAEL of 10
mg/kg/day, was selected for the acute Reference Dose and the
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short- and intermediate-term dermal risk assessments. A three-
generation reproduction study in rats is the basis for the chronic RfD.
The NOAEL in the study was 12.5 mg/kg/day. Captan is severely
irritating to the eyes and is classified in the Toxicity Category I.
Captan is severely irritating to the eyes, and classified in
Toxicity Category I based on corneal opacity in a rabbit study.
Captan has been classified as a B2 probable human carcinogen,
based on increased incidence of intestinal tumors in mice and rats.
To estimate human cancer risks, the Agency used a linear, low dose
extrapolation approach for captan. Based on intestinal tumors in
mice, a Q1 * of 2.4x10"3 (mg/kg/day)"1 was calculated.
Dietary Exposure
EPA has assessed the acute and chronic dietary risk posed by
captan, considering food and water sources of potential residues.
Residues of captan plus the metabolite THPI were included in the
anticipated residues for chronic (non-cancer) exposure and acute
exposure in meat and milk.
To determine the risk from captan in foods, the Agency
conducted acute, chronic (non-cancer) and chronic (cancer) dietary
analyses. The acute analysis used a probabilistic dietary risk
assessment estimated and the chronic dietary exposure was
assessed using refinements such as anticipated residues and
percent crop treated information. Since THPI is not considered
carcinogenic, the cancer risk assessment considered only the
residues of captan perse.
The Agency has reassessed captan food and feed tolerances
under the standards of FQPA. Crop group tolerances are being
established for various groups of related vegetables. Many of these
tolerances support seed treatment only, as the foliar applications
have not been permitted since the PD4 was issued in 1989. The
crop subgroup tolerance for caneberries (raspberries and
blackberries) is being established to support Special Local Needs
registrations in Oregon, Ohio, Pennsylvania, South Carolina, and
Washington.
Occupational and Residential Exposure
For occupational risk, different routes of exposures are
considered. As mentioned previously, captan is severely irritating to
the eyes, and for dermal exposure, a dermal absorption rate of
0.4%/hour was selected. The assessments also assume that captan
is taken up through the inhalation pathway to the same degree as
oral ingestion.
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Residential exposure to captan residues can occur by dermal
and inhalation routes. Also, postapplication residential dermal
exposure is expected from gardening and lawn activities on captan
treated areas. The Agency is concerned about postapplication
exposure to toddlers hand-to-mouth activity on treated lawns. The
registrant has agreed to voluntarily cancel this use. Captan is also
incorporated in paints and adhesives. Homeowner use of captan
containing paints and adhesives do not result in a risk concern to the
Agency.
Human Risk Assessment
The human health risk assessment evaluated toxicological and
residue data, and included dietary, drinking water, aggregate,
residential, and occupational exposure, as required by FQPA. The
FQPA Safety Factor was removed as there is no evidence that there
is increased sensitivity to infants and children from exposure to
captan, and the database is complete for evaluating FQPA concerns.
An acute probabilistic dietary risk assessment estimated that
acute dietary exposure to be 36% of the acute population adjusted
dose (aPAD) at the 99.9th percentile. The chronic non-cancer
dietary risk from exposure to captan is <2% of the chronic population
adjusted dose (cPAD). The upper bound dietary cancer risk for the
U.S. population is 1.3 x 10"7, which is below the Agency's level of
concern for lifetime excess cancer risk. The Agency has also
determined that there is no risk concern from the consumption of
captan residues in drinking water.
The Agency has also examined aggregate risk. These
assessments take into account available information concerning
exposures from the pesticide residue in food and all other exposures
for which there is reliable information including pesticide residues in
drinking water, exposure from pesticides uses in and around the
home, and exposure in non-residential settings such as, parks and
schools.
Residential exposure to captan may occur either during or after
a captan application to home gardens, ornamental flowers, shrubs, or
seeds. Exposure may also occur to golfers from treated golf
courses. Because of concern about toddlers exposed to treated
lawns, the technical registrants have agreed to voluntarily cancel
these uses. For all other residential uses, exposure and risks do not
exceed the Agency's level of concern.
The Agency has determined that acute and chronic dietary
(food and water) and cancer aggregate risks are not of concern.
Residential exposure from the use of captan around the home does
not exceed the Agency's level of concern when aggregated with food
and drinking water exposure.
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For occupational scenarios, most risk estimates were well
above 100 (values below 100 are a concern for captan) with cancer
risks ranging from 1.3 x 10"5 to 1.7 x 10"9. No additional mitigation is
required to address occupational cancer risks. There is a concern
for mixers and loaders of wettable powder for the aerial application of
captan. The Agency believes that this risk will be adequately
mitigated by requiring water soluble bags or a suitable reduction in
application rate. Reentry Intervals were also reevaluated during the
RED process and new REIs are being established ranging from 12-
hours for seed treatment uses to 4-days for ornamentals.
The Agency is aware of a proposed common mechanism of
carcinogenicity between captan and folpet, which implicates their
common metabolite, thiophosgene. Because thiophosgene is so
highly reactive in animal systems, its residues cannot be scientifically
quantified. Without measurable residues of the common metabolite,
it is difficult to relate exposures of captan to those of folpet since the
rate of thiophosgene formation may be different for both compounds.
The Agency has conducted a conservative aggregate assessment
for thiophosgene, assuming that it may cause cancer through both
captan and folpet, and has determined that this conservative risk is
not of concern.
The FQPA also directed the Agency to develop an Endocrine
Disrupter Screening Program, which was published in the Federal
Register of December 28, 1998 (63 FR 71541). The Program uses
a tiered approach and anticipates issuing a Priority List of chemicals
and mixtures for Tier 1 screening in the year 2000. As the Agency
proceeds with implementation of this program, further testing of
captan and end-use products for endocrine effects may be required.
Environmental
Assessment Environmental Fate
Captan dissipates rapidly in the environment, with a half-life of less
than 1 day, based on the results of hydrolysis and aerobic soil
studies. Parent captan is slightly mobile to relatively immobile in
various soils. The major degradates, THPI and THPAm, appear to
be mobile in soil. Though these degradates have the potential to
reach ground and surface water, they are not expected to be
persistent.
Ecological Effects
For ecological risk, only acute toxicity to freshwater fish is of
concern. There are no reported fish kills. Additionally, the Agency
has determined that captan is: practically nontoxic to avian species,
both on an acute and subacute basis; not acutely toxic to mammals,
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and relatively nontoxic to insects. Terrestrial and aquatic plant
toxicity is not a concern. Both THPI and THPAm were found to be
non-toxic to fish species tested. The Agency is requiring a 96-hour
oyster shell deposition study, however, these data are considered
confirmatory and are not expected to change the conclusions of this
risk assessment.
Risk Mitigation To reduce the risks posed by captan, the Agency is requiring
the following mitigation measures for captan-containing products:
Voluntary cancellation of the residential turf use;
Water-soluble packaging for the wettable powder
formulation used aerially
Various Personal Protective Equipment, including
chemical-resistant gloves, aprons/coveralls, eye
protection, and dust/mist respirators;
Revised labeling to reduce the risks to non-target aquatic
organisms;
Eye wash stations for occupational field workers; and
Double notification for workers entering treated fields.
Additional Data
Required
EPA is requiring the following additional generic studies for
captan to confirm its regulatory assessments and conclusions: the
96-hour oyster shell deposition study,72-3(b), Acute
Estuarine/Marine Toxicity - Mollusk; 81-1 Acute Oral Toxicity (rat);
81-2 Acute Dermal Toxicity (rat/rabbit); 81-3 Acute Inhalation Toxicity
(rat); 875.2400 Dermal Exposure; 875.2500 Inhalation Exposure;
product-specific data including product chemistry, revised
Confidential Statements of Formula (CSFs), and revised labeling for
reregistration. These data are considered to be confirmatory and are
not expected to change the conclusions of this RED.
Product Labeling
Changes Required All captan end-use products must comply with EPA's current
pesticide product labeling requirements and with the following. For a
comprehensive list of labeling requirements, please see Section V of
the captan RED document.
Regulatory
Conclusion
EPA has determined that products containing captan are
eligible for reregistration, except for those with uses on turf and
aerially-applied wettable powder formulations. Products applied to
turf at sod farms or golf courses are eligible for reregistration; uses at
all other turf sites are being voluntarily canceled. Wettable powder
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formulations that are applied aerially are eligible for reregistration,
provided either: 1) the products are packaged in water soluble
packaging; or 2) the application rates are reduced to a level that is no
higher than 1.2 Ib ai/A. The use of eligible captan products in
accordance with labeling specified in this RED will not pose
unreasonable adverse effects to humans or the environment. These
products will be reregistered once the required confirmatory generic
data, product specific data, CSFs, and revised labeling are received
and accepted by EPA. Products which contain active ingredients in
addition to captan will be reregistered when all of their other active
ingredients also are eligible for reregistration.
For More
Information EPA is requesting public comments on the Reregistration
Eligibility Decision (RED) document for captan during a 60-day time
period, as announced in a Notice of Availability published in the
Federal Register. To obtain a copy of the RED document or to
submit written comments, please contact the Pesticide Docket,
Public Information and Records Integrity Branch, Information
Resources and Services Division (7502C), Office of Pesticide
Programs (OPP), US EPA, Washington, DC 20460, telephone
703-305-5805.
Electronic copies of the RED and this fact sheet are available
on the Internet. See http://www.epa.gov/REDs.
Printed copies of the RED and fact sheet can be obtained from
EPA's National Center for Environmental Publications and
Information (EPA/NCEPI), PO Box 42419, Cincinnati, OH 45242-
2419, telephone 1-800-490-9198; fax 513-489-8695.
Following the comment period, the captan RED document also
will be available from the National Technical Information Service
(NTIS), 5285 Port Royal Road, Springfield, VA22161, telephone
703-605-6000.
For more information about EPA's pesticide reregistration
program, the captan RED, or reregistration of individual products
containing captan, please contact the Special Review and
Reregistration Division (7508C), OPP, US EPA, Washington, DC
20460, telephone 703-308-8000.
For information about the health effects of pesticides, or for
assistance in recognizing and managing pesticide poisoning
symptoms, please contact the National Pesticide
Telecommunications Network (NPTN) toll-free at 1-800-858-7378.
Their Internet address is ace.orst.edu/info/nptn.
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