The information in this profile may be out-of-date. It was last revised
in 1996. EXTOXNET no longer updates this information, but it may be useful
as a reference or resource.
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E X T O X N E T
A Pesticide Information Project of Cooperative Extension
Offices of Cornell University, Oregon State University, the
University of Idaho, and the University of California at Davis
and the Institute for Environmental Toxicology, Michigan State
University. Major support and funding was provided by the
USDA/Extension Service/National Agricultural Pesticide Impact
EXTOXNET primary files maintained and archived at Oregon State
Revised June 1996
Trade and Other Names:
Trade names include Acaraben, Akar 338, Benzilan, Benz-o-chlor,
ECB, Folbex, Geigy 338, and Kop-mite.
The U.S. Environmental Protection Agency (EPA) has classified all
formulations containing chlorobenzilate as Restricted Use
Pesticides (RUPs). RUPs may be purchased and used only by
certified applicators. It is classified RUP based on its ability
to cause tumors in mice, and its effects on the testes of rats.
Aerial and ground foliar sprays are restricted to citrus use in
the states of Arizona, California, Florida and Texas for the
control of mites. Considered toxicity class III - slightly toxic,
products containing chlorobenzilate bear the Signal Word CAUTION.
Chlorobenzilate is a chlorinated hydrocarbon compound. It is used
for mite control on citrus crops and in beehives. It has narrow
insecticidal action, killing only ticks and mites. Products are
available as emulsifiable concentrates or wettable powder
are available as emulsifiable concentrates or wettable powder
- Acute toxicity: Chlorobenzilate is
slightly toxic to humans. Symptoms of acute poisoning
from ingestion of chlorobenzilate include incoordination,
nausea, vomiting, fever, apprehension, confusion, muscle
weakness or pain, dizziness, wheezing, and coma. Symptoms
may occur within several hours after exposure. Death may
result from discontinued breathing or irregular
heartbeats [2,17]. Chlorobenzilate is a severe eye
irritant. It is mildly irritating to skin [2,17]. The
oral LD50 is 2784 to 3880 mg/kg for chlorobenzilate in
rats. The dermal LD50 is greater than 10,000 mg/kg in
rats and rabbits [2,9].
- Chronic toxicity: Prolonged or repeated
exposure to chlorobenzilate may cause the same effects as
acute exposure [2,17]. After continuous exposure to
chlorobenzilate, 16 out of 73 workmen tested had abnormal
electrical activity of the brain. The most severe brain
activity changes were seen in those persons exposed to
the herbicide for 1 to 2 years [2,17]. Chronic skin
exposure to chlorobenzilate may cause inflamed skin or
rashes. Chronic eye exposure may cause conjunctivitis
[2,17]. Autopsies revealed intestinal irritation and
bleeding in the lungs of rats poisoned by dietary doses
of 25 mg/kg/day of chlorobenzilate [2,17]. Liver damage
may be caused by repeated or prolonged contact [2,17].
- Reproductive effects: A three-generation
rat reproduction study resulted in reduced testicular
weights, but did not affect reproduction. The results of
another study indicate that chlorobenzilate does not
adversely affect reproductive performance at dosage
levels up to 100 mg/kg/day [2,29]. Atrophy of testes was
observed in a 2-year study of rats [2,17]. It is unlikely
that chlorobenzilate will cause reproductive toxicity in
humans at expected exposure levels.
- Teratogenic effects: No data are
- Mutagenic effects: No data are currently
- Carcinogenic effects: Chlorobenzilate is
a suspected carcinogen in animals and a possible human
carcinogen. It has produced liver tumors in mice, but the
evidence for carcinogenicity in rats is uncertain .
- Organ toxicity: Exposure to
chlorobenzilate may affect the central nervous system,
the kidneys, and the liver [2,17].
- Fate in humans and animals:
Chlorobenzilate is rapidly excreted by humans, usually
within 3 to 4 days [2,17]. After doses of 12.8 mg/kg/day
to dogs, for 5 days a week for 35 weeks, about 40% of the
dose was excreted unchanged or as urinary metabolites. No
significant storage in fat of dogs or rats was reported
[2,17]. Detectable traces of chlorobenzilate were found
in urine collected from Texas and Florida citrus-grove
growers and workers. The results showed low levels in
harvest season pickers exposed to little or no
chlorobenzilate exposure, and higher levels among
permanent or semi-permanent workers employed during the
spraying season. Among all workers, urinary values ranged
from 0 to 63.6 ppm . This acaricide has not been
found in human milk in the U.S.  .
- Effects on birds: Chlorobenzilate is
slightly toxic to practically nontoxic to birds. The
7-day dietary LC50 for chlorobenzilate is 3375 ppm in
bobwhite quail. Its 5-day dietary LC50 in mallard ducks
is greater than 8000 ppm .
- Effects on aquatic organisms: An LC50
(96 hour) of 0.7 mg/L in rainbow trout and 1.8 mg/L in
the bluegill indicate that chlorobenzilate is moderately
to highly toxic to different species of fish [9,17].
Chlorobenzilate is not expected to bioconcentrate in
aquatic organisms .
- Effects on other organisms:
Chlorobenzilate is nontoxic to beneficial insects,
including honeybees .
- Breakdown in soil and groundwater:
Chlorobenzilate has a low persistence in soils [12,14].
Its half-life in fine sandy soils was 10 to 35 days after
application of 0.5 to 1.0 ppm. The removal is probably
due to microbial degradation . Because
chlorobenzilate is practically insoluble in water and it
adsorbs strongly to soil particles in the upper soil
layers, it is expected to exhibit low mobility in soils,
and to therefore be unlikely to leach to groundwater
. Following a 5-day application of chlorobenzilate to
several different citrus groves employing various tillage
treatments, chlorobenzilate was not found in subsurface
drainage waters, nor in surface runoff waters . Due
to its strong adsorption to soil particles and low vapor
pressure, chlorobenzilate is not expected to volatilize
from soil surfaces [12,32].
- Breakdown in water: Chlorobenzilate
adsorbs to sediment and suspended particulate material in
water. It is practically insoluble in water . It is
not expected to volatilize but may be subject to
- Breakdown in vegetation: Chlorobenzilate
is fairly persistent on plant foliage and may be
phytotoxic, or poisonous, to some plants . It is not
absorbed or transported throughout a plant.
Chlorobenzilate residues have been found in the peel of
citrus fruit. Its half-life in lemon and orange peels was
from 60 to over 160 days . Spraying 200, 1000 and
5000 ppm chlorobenzilate in emulsions or suspensions
caused leaf browning on most treated crops . When
chlorobenzilate was applied to the surface of soybean
leaves, the miticide was quite stable and very little was
absorbed and moved (or translocated) from one part of the
plant to another .
- Appearance: Technical chlorobenzilate, a
brownish liquid, contains approximately 90% active
compound . Pure chlorobenzilate is a yellow solid
- Chemical Name: ethyl
- CAS Number: 510-15-6
- Molecular Weight: 325.21
- Water Solubility: 10 mg/L @ 20 C 
- Solubility in Other Solvents: benzene
v.s.; acetone v.s.; methyl alcohol v.s.; toluene v.s.;
hexane and alcohol v.s. 
- Melting Point: 37.5 C 
- Vapor Pressure: 0.12 mPa @ 20 C 
- Partition Coefficient: Not Available
- Adsorption Coefficient: 2000 (estimated)
- ADI: 0.02 mg/kg/day 
- MCL: Not Available
- RfD: 0.02 mg/kg/day 
- PEL: Not Available
- HA: Not Available
- TLV: Not Available
P.O. Box 18300
Greensboro, NC 27419-8300
- Phone: 800-334-9481
- Emergency: 800-888-8372
References for the information in this PIP can be found in
Reference List Number 6
information in this profile does not in any way replace or
supersede the information on the pesticide product labeling or
other regulatory requirements. Please refer to the pesticide