United StM« Offio* of P«Htdd« uaa Toxic Sutvttncw
Environmental Protection Offiet of PMtioid* Programs (TS-766C)
Agency WMhington. DC 20460
540/FS-89-026
• vvEPA Pesticide
Fact Sheet
Name of Chemical: Carbofuran
Reason for Issuance: Special Review—Preliminary Determination
Date ISSUed: January 5, 1989
Fact Sheet Number: 189
1. DESCRIPTION OF CHEMICAL
Common Name: Carbofuran
Chemical Name: 2,3-dihydro-2,2-dimethyl-7-benzofuranyl
methylcarbamate
Chemical Family: Carbamate
Trade Name: Furadan*
EPA Shaughnessy Code: 090601
Chemical Abstracts Service (CAS) Number: 1563-66-2
Year of Initial Registration: 1969
Pesticide Type: Insecticide, neraaticide
U.S. Producer: FMC Corporation
2. USE PATTERNS AND FORMULATIONS
Carbofuran is currently registered on a variety of fruit
and field crops, vegetables, tobacco, ornamentals, and
forest tree seedlings. Approximately 7 to 10 million
pounds of active ingredient (Ib ai) are applied to these
sites per year. From 6 to 9 million Ib ai of the annual
usage is accounted for by the granular formulation. The
carbofuran granular formulation was placed in Special
Review in 1985 based on the avian hazard.
Types and Methods of Application: Aerial and ground.
Application Rates: 0.1 to 19.9 Ib ai/acre (granular)
0.05 to 10.1 Ib ai/acre (flowable)
Types of Formulations: Granular, flowable, and wettable
powder formulations and a spike
product.
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3. SCIENCE FINDINGS
Chemical Characteristics:
Physically/ technical carbofuran is a white crystalline
solid that has a melting point of 153 to 154 °C (pure material).
Carbofuran is stable under natural or acidic conditions and is
unstable under alkaline conditions.
Toxicological Characteristics:
The Agency evaluated information concerning the hazard
to humans from carbofuran and its major alternatives. Based
on the available data/ carbofuran does not appear to pose
a chronic health hazard because it has not shown positive
oncogenic/ teratogenic/ or reproductive effects. The data
base is complete and is considered acceptable. The data
bases for carbofuran's alternatives do not suggest adverse
health effects however the data bases are not complete so a
full conclusion cannot be drawn. The Agency has required
that these data be submitted to complete the data bases.
Based on data on acute health effects, the acute oral
hazard of carbofuran is the same order of magnitude as
fonophos, phorate/ and terbufos, but is less than aldicarb/
and greater than the other major alternatives.
Environmental Characteristics:
The Agency also evaluated the potential for ground
water contamination from carbofuran. The environmental
fate data indicate that carbofuran is highly mobile and
has a potential to leach. Simulation modeling supports
this hypothesis. The environmental fate data indicate
that under conditions of low pH and low temperature,
residues of carbofuran could persist after leaching into
ground water. Since these conditions are not widespread
in the United States, most leaching of carbofuran will
probably not result in significant concentrations at the
wellhead. Monitoring information for Long Island, New
York; Maryland; and Massachusetts show the highest and
most frequently found residues in ground water. Concentra-
tions above 36 parts per billion, the draft lifetime Health
Advisory Level/ will probably only occur in localized/
worst-case situations. The Agency will be requiring the
registrants to revise the product labels' ground water
advisory statement.
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Ecological Effects:
To evaluate the avian hazard from the granular formu-
lation/ the Agency evaluated the risk to birds based on
(1) acute avian toxicity/ (2) exposure/ (3) field studies/
(4) bird kill incidents/ and (5) population effects.
Based on laboratory data/ the Agency concluded that
granular carbofuran is acutely toxic to birds/ and that
a single granule may kill a small bird. Birds are expected
to be present at the time of carbofuran application*
Dietary exposure occurs from direct ingestion of granules
and exposure from ingestion of contaminated soil invertebrates
such as earthworms. Predatory birds may be secondarily
exposed to carbofuran by feeding on contaminated vertebrates
such as small birds.
There were 6 field studies conducted at 11 locations
that investigated the loss of birds from label-directed/
so il-i ncorpora ted uses of lt)G and 15G applied as band
and in-furrow applications and 10G using specialized
equipment. All studies consistently resulted in bird
mortality, regardless of application rate or methods
which employed commonly practiced techniques for soil
incorporation of granules. Both direct and secondary
poisoning occurred.
Bird kill incidents from direct poisoning from carbofuran
granules have occurred in several crops in various areas
of the country and Canada. The types of birds varied and
included both migratory and nonmigratory birds. Bird
mortality was frequently associated with at-planting
application/ but has occurred with other uses throughout
the year. Direct poisoning of birds has caused over 40
reported bird kill incidents.
Secondary poisoning incidents have also occurred and
involved bald eagles, red-tailed hawks, red-shouldered hawks,
northern harriers, and others.
The direct and secondary bird kill incidents that have
been reported underestimate the number of incidents actually
taking place because of the problems associated with the
reporting of bird kill incidents and with carcass removal
by predators.
Populations of declining or endangered species may
be present in areas where granular carbofuran is applied.
The Agency cited documented population declines of the
red-shouldered hawk/ loggerhead shrike, field sparrow/
Henslow's sparrow, and others. Statistically significant
declines have been measured for several species.
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While the Agency does not consider granular carbofuran
to be the sole causative factor in the decline of the bird
species discussed/ carbofuran is one of the most highly
toxic pesticides to which these birds are exposed. Given
its widespread use in agriculture/ carbofuran is likely
to be responsible for bird deaths in these species. The
Agency concluded that granular carbofuran can/ therefore/
be an important additive factor in the declines.
The Fish and Wildlife Service's Division of Endangered
Species and Habitat Conservation (DESHC) indicated in its
Biological Opinion for carbofuran that the Aplomado
falcon/ Attwater's greater prairie chicken, and Aleutian
Canada goose were the bird species jeopardized by the use
of carbofuran and indicated that the use be eliminated in
certain areas. DESHC also indicated that the bald eagle,
whooping crane, and Mississippi sandhill crane may be
adversely affected. DESHC recommended prohibiting the use
of carbofuran in certain areas to avoid impact on these
species. .
The Agency has examined other statutes that are intended
to protect birds and that compliment FIFRA. The Migratory
Bird Treaty Act prohibits the taking "by any means or in
any manner" individual birds of migratory species that are
listed in the Act's regulations. Birds of more than 20
such species have been reported killed by carbofuran.
Likewise, the Bald and Golden Eagle Protection Act prohibits
takings of the bald and golden eacles and the Endangered
Species Act prohibits taking of threatened or endangered
species. A number of bald eagles killed by carbofuran have
been reported and the Fish and Wildlife Service has determined
that carbofuran use threatens the continued existance of
several endangered species.
The Agency has concluded that, in general carbofuran
poses the greatest risk to birds as compared with other
granular pesticides, including its alternatives. This
conclusion was based on estimations of the numbers of LDSOs
per square foot of treated ground according to labeled use
rates and methods.' The field studies and reported bird
kill incidents for carbofuran confirm the Agency's conclusion
that carbofuran poses a high risk. This approach for
comparative risk analysis can be used by the Agency to
identify other high risk pesticides for which regulatory
action would be appropriate.
BENEFITS ANALYSIS
The Agency analyzed the benefits of carbofuran use on
10 sites. The percentage of granular carbofuran use on
these sites is as follows: 68 percent for corn, 14 percent
for sorghum, 5 percent for soybeans, 2 percent for rice, 5
percent for peanuts, and 2 percent for tobacco. Also, less
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than 1 percent is used on each of the following sites: cotton/
cranberries/ sunflowers/ and pineseed orchards. These uses
encompass over 95 percent of the granular carbofuran usage
and about 85 percent of all carbofuran formulation usage.
If carbofuran is not available for treatment of the
10 sites/ the Agency estimated an annual grower impact
that ranged from approximately $22.8 to $33.0 million.
The largest economic impact from cancellation of granular
carbofuran will be for rice since no registered alternatives
are available for control of the rice water weevil. The
Agency estimates a grower impact to be $12.2 million
annually; a $6.1 million decrease in Federal deficiency
payments to rice growers would indicate a loss to society
of $6.1 million.
Corn is the major use site for carbofuran/ and cost-
effective/ efficacious alternatives are available. No
changes in costs of production/ yields/ or revenues are
expected. The corn insecticide market is highly competitive/
and viable alternatives with similar pesticide performance
are available at comparable cost per acre.
The carbofuran market for corn has been declining
since 1978/ and current usage is approximately one-third
the level it was in 1978. By 1986, the market share held
by carbofuran. dropped to less than 15 percent where/ in
terms of acre treatments, it ranked fourth out of the five
major corn insecticides. The reasons for the decline are
not clear, but could include loss in efficacy, spectrum
of control, and others.
Carbofuran is applied to nonflooded cranberries in
Washington and Oregon to control the black vine weevil.
Carbofuran is the only pesticide registered for black vine
weevil larvae control. Acephate is an efficacious insecticide
for control of the adults. The impact on cranberries, without
considering acephate's use/ is expected to occur over a
7-year period due to the perennial nature of the crop.
Overall impacts cotuld range from $7 million to $7.7 million
over this period.
For the remaining crops/ the Agency does not anti-
cipate major impacts. The overall economic impact from
cancellation is not expected to result in significant
changes in either production costs or outputs.
The Agency also evaluated aspects of carbofuran use
that are not easily quantifiable. For example/ only one
carbamate (trimethacarb) would be available for corn
growers who rotate organophosphate and carbamate insecticides
to delay development of resistance in soil pests/ although
the Agency recognizes that some cross-resistance with
organophosphates could occur. Also, carbofuran has
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residual and systemic properties and a broad spectrum of
control. However, repeated use of carbofuran may lead to
an apparent increase in soil microbial populations that
are capable of reducing its effectiveness.
5. SUMMARY OF REGULATORY POSITION AND RATIONALE
In weighing the risks and benefits, the Agency reviewed
a number of options other than cancellation to reduce the
risk to birds. Among these measures were (1) additional
precautionary labeling regarding the hazard to birds, (2)
limiting carbofuran use to certain months of the year,
(3) limiting application geographically, and (4) implementing
a risk reduction program. The Agency evaluated these
measures and determined that they would not adequately
mitigate the risk.
As a result, the Agency is proposing to cancel granular
carbofuran use on all sites. The decision to cancel
granular carbofuran use, is, based on the conclusion that
the risk to birds outweighs the benefits of use. Because
of the substantial risks and substantial benefits associated
with the use of carbofuran on rice to control the rice
water weevil, the Agency has requested specific additional
information pertaining to the associated risks, benefits,
usage, and additional means of control.
6. CONTACT PERSON
Jay Ellenberger
Special Review Branch
Special Review and Reregistration Division
Office of Pesticide Programs (TS-767C)
401 M Street, S.W.
Washington, D.C. 20460
(703) 557-7400
DISCLAIMER: The information presented in this Pesticide Fact
Sheet is for informational purpose only and may not be used
to fulfill data requirements for pesticide registration or
reregistration.
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