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The information in this profile may be out-of-date.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.

Please visit the National Pesticide Information Center (NPIC) to find updated pesticide fact sheets. If you don't find a fact sheet related to your question, feel free to call 1-800-858-7378. NPIC is open five days a week from 8:00am to 12:00pm Pacific Time.

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E X T O X N E T

Extension Toxicology Network

Pesticide Information Profiles

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 Assessment Program.

EXTOXNET primary files maintained and archived at Oregon State University

Revised June 1996

Chlorobenzilate

Trade and Other Names: Trade names include Acaraben, Akar 338, Benzilan, Benz-o-chlor, ECB, Folbex, Geigy 338, and Kop-mite.

Regulatory Status: 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.

Chemical Class: chlorinated hydrocarbon

Introduction: 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 formulations.

Formulation: Products are available as emulsifiable concentrates or wettable powder formulations.

Toxicological Effects:

• 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 currently available.
• Mutagenic effects: No data are currently available.
• 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 [2].
• 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 [30]. This acaricide has not been found in human milk in the U.S. [17] .

Ecological Effects:

• 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 [31].
• 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 [12].
• Effects on other organisms: Chlorobenzilate is nontoxic to beneficial insects, including honeybees [9].

Environmental Fate:

• 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 [12]. 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 [12]. 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 [32]. 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 [17]. It is not expected to volatilize but may be subject to biodegradation [12].
• Breakdown in vegetation: Chlorobenzilate is fairly persistent on plant foliage and may be phytotoxic, or poisonous, to some plants [33]. 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 [17]. Spraying 200, 1000 and 5000 ppm chlorobenzilate in emulsions or suspensions caused leaf browning on most treated crops [17]. 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 [34].

Physical Properties:

• Appearance: Technical chlorobenzilate, a brownish liquid, contains approximately 90% active compound [17]. Pure chlorobenzilate is a yellow solid [9].
• Chemical Name: ethyl 4.4'-dichlorobenzilate [9]
• CAS Number: 510-15-6
• Molecular Weight: 325.21
• Water Solubility: 10 mg/L @ 20 C [9]
• Solubility in Other Solvents: benzene v.s.; acetone v.s.; methyl alcohol v.s.; toluene v.s.; hexane and alcohol v.s. [9]
• Melting Point: 37.5 C [9]
• Vapor Pressure: 0.12 mPa @ 20 C [9]
• Partition Coefficient: Not Available
• Adsorption Coefficient: 2000 (estimated) [14]

Exposure Guidelines:

• ADI: 0.02 mg/kg/day [27]
• MCL: Not Available
• RfD: 0.02 mg/kg/day [8]
• PEL: Not Available
• HA: Not Available
• TLV: Not Available

Basic Manufacturer:

Ciba-Geigy Corp.
P.O. Box 18300
Greensboro, NC 27419-8300

• Phone: 800-334-9481
• Emergency: 800-888-8372
  

References:

References for the information in this PIP can be found in Reference List Number 6

DISCLAIMER: The 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 product labeling.