United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508C)
EPA-738-F-02-012
September 2002
vvEPA R.E.D. FACTS
Pesticide
Reregistration
738F02012
Use Profile
Endosulfan
All pesticides sold or distributed in the United States must be registered by
EB\, 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
Rxxl Quality Protection Act of 1996, 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 toxiciry. 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 feet
sheet summarizes the information in the RED document for reregistration case
0014, endosulfan.
Endosulfan is a broad spectrum contact insecticide and acaricide registered
for use on a wide variety of vegetables, fruits, cereal grains, and cotton, as well
as ornamental shrubs, trees, vines, and ornamentals for use in commercial
agricultural settings. Total average annual use of endosulfan is estimated at
approximately 1.38 million pounds of active ingredient (Ibs. ai), according to
Agency and registrant estimates. Crops with the highest average percent drop
treated are: squash (40%), eggplant (41%), cantaloupe (31%), sweet potato
(31%), broccoli (26%), pears (20%), and pumpkins (20%). Crops with the
highest sales in 2001 include: cotton (14.2%), cantaloupe (13.2%), tomatoes
(12.2%), and potatoes (8.15%).
Endosullan is formulated as a liquid emulsifiable concentrate ( 9-34% ai)
and wettable powder (1-50% ai). The wettable powder formulation is frequently
packaged in water soluble bags. Endosulfan can be applied by groundboom
sprayer, fixed-wing aircraft, chemigation (potatoes only), airblast sprayer, rights-
of-way sprayer, low pressure handwand sprayer, high pressure handwand
sprayer, backpack sprayer and dip treatment.
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Regulatory
History
Human Health
Assessment
Endosulfan was first registered as a pesticide in the U.S. in 1954 to control
agricultural insect and mite pests on a variety of field, fruit, and vegetable crops.
A Registration Standard dated September 17, 1981, and a Guidance Document
dated April 1982 were issued for endosulfan, which required additional generic
and product-specific data for the manufacturing products of the technical
registrants. Since the Guidance Document was issued, there have been seven
DCIs generated: 10/23/85, 5/19/86, 5/27/86, 1/30/87, 6/19/87, 9/02/92, and
5/10/94 concerning the potential formation of chlorinated dibenzo-p-dioxins and
dibenzofurans in technical endosulian products. An additional DCI was issued in
October 1994, which primarily concerned residue chemistry data deficiencies.
Further, in 1991, the technical registrants amended labels to incorporate a
300-foot spray drift buffer for aerial applications between treated areas and water
bodies. This setback was adopted in order to address concerns about
contamination of water and risks to aquatic organisms. In 2000, the technical
registrants amended technical product labels to remove all residential use patterns.
Currently, there are 94 endosulian products registered.
Toxicity
Endosulfan generally has been shown to have high acute oral and
inhalation toxicity as well as slightly toxic dermal toxicity. It is an irritant to the
eyes and is not a dermal sensitizer. Endosulfan is neither mutagenic nor
carcinogenic. Endosulfan primarily affects the nervous system. Toxic effects
observed in animals from acute, subchronic, developmental neurotoxicity, and
chronic/carcinogenic toxicity studies found that endosulfan causes neurotoxic
effects, which are believed to result from over-stimulation of the central nervous
system. Further, there is evidence (effects observed in a submitted chronic oral
toxicity study in rats) that endosulfan acts as an endocrine disrupter. However,
further investigation is necessary to determine the relevance and impact of such
findings on public health.
Dietary Exposure
EPA has assessed dietary risk by estimating exposure to endosulian
residues from consumption of food and drinking water that can occur over a
single-day (acute) or longer (chronic). Generally, a dietary (food) risk estimate
that is less than 100% of the acute or chronic Population Adjusted Dose does not
exceed the Agency's risk concern. Acute risk estimates from exposures to food,
associated with the use of endosulian exceed the Agency's level of concern for
some population subgroups. For example, for exposure resulting from
applications of endosulfan, for the most exposed population subgroup, children 1-
6 years old, the percent acute PAD value is 150% at the 99.9th percentile of
exposure from consumption of food alone. The crops that contributed the most
to the risks of concern are succulent beans and peas. Chronic dietary (food)
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exposure estimates are below the Agency's level of concern for all
subpopulations. POT the most highly exposed subpopulation, children 1-6 years
old, the percent chronic PAD value is 17% from consumption of food alone.
Drinking water exposure to endosulfan can occur through ground and
surface water contamination. ERA. used modeled Tier 2 estimates of endosulian
and endosulfan sulfate to estimate risk for acute exposures. Taking into account
the supported uses of endosulfan, the Agency concluded that residues of
endosulfkn in drinking water are of concern. Drinking water estimates for
chronic exposures, based on models, from both ground and surface water are not
of concern.
Risk from All Registered Pesticide Endosulfan Exposures
To assess risks from all endosulfan exposures, the Agency combined risk
from food and drinking water exposure only. The technical registrants are not
supporting residential or other non-occupational uses of endosulfan. As a result,
these use patterns have not been considered for regulatory purposes at this time.
The acute estimated drinking water concentrations for endosulfan are above the
acute drinking water level of comparisons (DWLOCs) for infants < 1 year and
the most sensitive population subgroup, children 1-6 years old. The chronic
estimated drinking water concentrations for the U.S. general population and all
population subgroups are below the chronic drinking water levels of comparisons
(DWLOCs) for the U.S. general population and all population subgroups and,
therefore, are not of concern.
Occupational Exposure
Occupational handlers can be exposed to endosulfan through mixing,
loading and/or applying a pesticide or re-entering treated sites. Occupational
handlers of endosulfan include individual farmers or growers who mix, load
and/or apply pesticides and professional or custom agricultural applicators. The
post-application occupational risk assessment considered exposures to workers
entering treated sites in agriculture.
Risk for all of these potentially exposed populations is measured by a
Margin of Exposure (MOE), which determines how close the occupational
exposure comes to a NOAEL. Generally, MOEs greater than 100 are not of
concern. Restricted Entry Intervals (REIs) are 24 hours on current endosulfan
labels. The Agency has determined that there are potential mixer, loader,
applicator as well as post-application exposures to occupational handlers. Based
on current use patterns, there are some short-term dermal and inhalation risks of
concerns for workers who mix, load and apply endosulfan to agricultural sites as
well as to those workers who re-enter a treated area following application of
endosulfan.
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Environmental
Assessment
Risk Mitigation
Measures
Ecological risks are also of concern to the Agency. The environmental
risk assessment suggests that exposure to endosulian could result in both acute
and chronic risks of concern for terrestrial and aquatic organisms. Exposure to
endosulian has resulted in both reproductive and development effects in nontarget
animals, particularly birds, fish and mammals.
To mitigate human health and ecological risks of concern for
endosulfan, the following measures will be implemented:
Dietary (Food) Risk
• Delete use on succulent beans, succulent peas, spinach, and grapes
Dietary (Drinking Water) and Ecological Risk
Several mitigation measures are needed to reduce the potential for
contamination of drinking water.
• Delete use on pecans;
• Reduce maximum seasonal application rates from 31bs./ai/A to 2.5
Ibs./ai/A for pome fruit, stone fruit, and citrus;
• Reduce maximum seasonal application rate from 3 Ibs./ai/A to 2 lbs,/ai/A
for melons, cucurbits, lettuce, tomatoes, sweet potatoes, cotton (ground),
broccoli, cauliflower, cabbage, kohlrabi, brussels sprouts, strawberries,
filberts, walnuts, almonds, macadamia nuts, peppers, eggplant, potatoes,
carrots, dry beans, dry peas, and tobacco;
• Reduce maximum seasonal application rate from 3 Ibs./ai/A to 1.5
Ibs./ai/A for sweet corn, cotton (aerial) and blueberries;
• Reduce maximum seasonal application rate from 3 Ibs./ai/A to 1 Ib./ai/A
for celery;
• Require 100 ft. spray buffer for ground applications between a treated area
and water bodies;
• Require 30 ft. maintained vegetative buffer strip between a treated area and
water bodies;
• Require all products to be Restricted Use;
• Restrict use on cotton to AZ, CA, NM, OK and TX only; and
• Restrict use on tobacco to IN, KY, OH, PA, TN and WV only.
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Occupational Risk
• Require all wettable powers to be packaged in water soluble bags;
• Cancel use of wettable powders on tomatoes, sweet corn, sweet potatoes,
cotton, small grains, alfelfe (seed), carrots, dry beans, dry peas,
pineapples, and tobacco;
• Cancel aerial application using the wettable powder formulation on pome
fruits, stone fruits, citrus, blueberries, strawberries, collard greens (seed),
kale (seed), mustard greens (seed), radish (seed), turnip (seed), rutabaga'
(seed), broccoli, (seed), cauliflower (seed), kohlrabi (seed), cabbage (seed),
filberts, walnuts, almonds, and macadamia nuts;
• Require closed mixing/loading systems for aerial application using the EC
formulation on pome fruits, stone fruits, citrus, sweet corn, sweet potatoes,
cotton, collard greens (seed), kale (seed), mustard greens (seed), radish
(seed), turnip (seed), rutabaga (seed), broccoli, (seed), cauliflower (seed),
kohlrabi (seed), cabbage (seed), blueberries, small grains, alfelfe (seed), '
filberts, walnuts, almonds and macadamia nuts;
• Require closed cabs for airblast applications on pome fruits, stone fruits,
citrus, filberts, walnuts, almonds and macadamia nuts;
1 Prohibit use of high pressure handwands with rates greater than 0.005
Ibs/ai/gal;
Increase REI to 48 hours for all crops except as noted in the following
bullets;
Increase RH for WP products to 3 days for melons and cucurbits;
Increase REI for WP products to 4 days for lettuce, celery, pome fruit,
stone fruit, citrus, collard greens, kale, mustard greens, radish, turnip,'
rutabaga, ornamental trees and shrubs;
Increase REI for WP products to 5 days for collard greens (seed), kale
(seed), mustard greens (seed), radish (seed), turnip (seed) and rutabaga
(seed);
Increase REI for WP products to 9 days for blueberries, broccoli,
cauliflower, kohlrabi, cabbage, and brassels sprouts;
Increase REI for WP products to 12 days for broccoli (seed), cauliflower
(seed), kohlrabi (seed), and cabbage (seed);
Increase REI for EC products to 3 days for sweet potatoes
Increase REI for EC products to 4 days for broccoli, cauliflower, kohlrabi,
cabbage, and brussels sprouts;
Increase REI for EC products to 6 days for blueberries;
Increase RH for EC products to 7 days for broccoli (seed), kohlrabi
(seed), and cabbage (seed); and
Increase REI for EC products to 17 days for sweet com.
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Stakeholder
Process
Additional Data
Required
Given the toxicity and persistence of endosulfan and potential risks to
aquatic organisms, the Agency has developed a number of mitigation measures
in order to reduce the risks to aquatic organisms outlined in this document.
While the Agency believes that these measures will reduce the potential for
exposures to aquatic organisms and reduce the overall environmental loading of
endosulfan, it also believes that in specific geographic areas where conditions
exist that make aquatic organisms especially vulnerable (e.g., shallow, leaky
aquifers, highly erodible lands, the presence of especially sensitive organisms and
high use of endosulfen) additional measures may be identified. In order to more
fully evaluate the risks in these vulnerable areas; the risk management strategies
that may be in place or could potentially be implemented in such areas (e.g., use
of retention ponds) to reduce exposure; and the benefits of the use of endosulfan
in those areas, the Agency is planning to conduct a stakeholder process to
accomplish this objective. Further, the impacts of atmospheric transport may
require additional evaluation during this time period.
Additional mitigation measures may be needed following the completion of this
process.
EPA is requiring the following additional generic studies for endosulfan to
confirm its regulatory assessments and conclusions:
• OPPTS 850.2100: Avian acute oral toxicity of bobwhite quail and mallard
ducks
• OPPTS 850.2200: Avian subchronic oral toxicity of bobwhite quail and
mallard ducks
• OPPTS 850.2300: Avian reproduction study
• OPPTS 850.1075: Freshwater fish acute toxicity study of bluegill sunfish
• OPPTS 850.1300: Early life stage fish
• OPPTS 850.1350: Life cycle invertebrate
• OPPTS 850.1500: Freshwater fish full life cycle using rainbow trout
• OPPTS 850.1075: Estuarine/marine fish acute toxicity study
• OPPTS 850.1035: Estuarine/marine invertebrate acute toxicity study of
• mysid shrimp
• OPPTS 850.1735: Whole sediment acute toxicity testing using a
freshwater invertebrate
• OPPTS 850.1740: Whole sediment acute toxicity testing using a
estuarine/marine invertebrate
• OPPTS 850.1735S: Whole sediment acute toxicity testing using a
freshwater invertebrate
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• OPPTS 850.174QS: Whole sediment acute toxicity testing using an
estuarine/marine invertebrate
• 164-2 (Special Study): Vegetative buffer effectiveness study
• OPPTS 835.7100: Groundwater monitoring study
• OPPTS 835.7200: Surface drinking water monitoring study
• OPPTS 870.6200: Subchronic Neurotoxicity - Rat
* OPPTS 870.6300: Developmental Neurotoxicity Toxicity Study - Rat
• OPPTS 860.1380: Storage stability (oils seed, non-oily grain and processed
commodities)
• OPPTS 860.1500: Crop field trials for the following raw agricultural
commodities: barley hay, and pearled barley; oat forage, hay, and rolled
oats; rye forage; wheat forage, and hay
• OPPTS 860.1500: Crop field trials for tobacco and a pyrolysis
• OPPTS 860.1520: Magnitude of residue in processed food/feed
commodities
• OPPTS 875.1100: Dermal outdoor exposure for applying dip treatments to
trees and roots or whole plants
• OPPTS 875.1700: Product use information for applying dip treatments to
trees and roots or whole plants
The Agency is also requiring product-specific data including product
chemistry and acute toxicity studies, revised Confidential Statements of Formula
(CSFs), and revised labeling for reregistration.
Regulatory The Agency has assessed all 80 tolerances for endosulian and can make a
Conclusion FQPA safety determination based on a review of the dietary (food and drinking
water), ecological and occupational risks associated with the supported uses of
currently registered pesticides containing endosulian.
Agricultural uses of endosulian based on approved labeling pose
occupational risks of concern and ecological risks that constitute unreasonable
adverse effects on the environment. However, the Agency believes these risks
can likely be mitigated to levels below concern through changes to pesticide
labeling and formulations. Accordingly, the Agency has determined that
endosulian is eligible for reregistration provided that: (1) additional required data
will confirm this decision for occupational exposures associated with the
application of dip treatment to roots or whole plants and ecological risks; and (2)
the risk mitigation outlined in the RED are adopted, and label amendments are
made to reflect these measures. Further, if vulnerable areas in specific
geographic areas are identified as a result of the stakeholder process, additional
ecological risk mitigation measures may be necessary to protect especially
sensitive organisms. The endosulfen RED document includes guidance and time
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frames for complying with any label changes for products containing endosulian.
For More
Information
EPA is requesting public comments on the Reregistration Eligibility
Decision (RED) document for endosulian during a 60-day time period, as
announced in a Notice of Availability published in the Fsderal 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 number 703-305-
5805.
Electronic copies of the RED, this Fact Sheet, and all supporting
documents are available on the Internet. See http://www.epa.gov/REDs.
The Agency has also established an official record for this action under docket
control numbers OPP-34242 and eDocket OPP-2002-0262.
Printed copies of the RED and feet sheet can be obtained from EPA's
National Service Center for Environmental Publications (EPA/NSCEP), PO Box
42419, Cincinnati, OH 45242-2419, telephone 1-800490-9198; fex 513489-
8695.
Following the comment period, the endosulian RED document also will be
available from the National Technical Information Service (NTIS), 5285 Port
Royal Road, Springfield, VA 22161, telephone 1-800-553-6847, or 703-605-
6000.
For more information about EPA's pesticide reregistration program, the
endosulfan RED, or reregistration of individual products containing endosulfan
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 Raticide Information Center (NPIC). Call toll-free 1-800-858-7378,
from 6:30 am to 4:30 pm Pacific Time, or 9:30 am to 7:30 pm Eastern Standard
Time, seven days a week. Their internet address is http://npic.orst.edu.
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