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The information in this profile may be out-of-date.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

Propoxur

Trade and Other Names: Trade and other names for propoxur include Arprocarb, Bay 9010, Baygon, Bayer 39007, Bifex, Blattanex, Brifur, Bolfo, BO Q 5812315, ENT 25671, Invisi-Gard, OMS 33, PHC, Pillargon, Prentox Carbamate, Propogon, Proprotox, Propyon, Rhoden, Sendran, Suncide, Tendex, Tugen, Unden, and Undene.

Regulatory Status: Propoxur is a highly toxic compound; various formulations are in diffferent EPA toxicity classes. It is a General Use Pesticide (GUP), although some formulations may be for professional use only. Labels for pesticide products containing Propoxur must bear the Signal Word DANGER, WARNING or CAUTION, depending on the formulation.

Chemical Class: carbamate

Introduction: Propoxur is a non-systemic insecticide which was introduced in 1959. It is compatible with most insecticides and fungicides except alkalines, and may be found in combination with azinphosmethyl, chlorpyrifos, cyfluthrin, dichlorvos, disulfoton, or methiocarb. It is used on a variety of insect pests such as chewing and sucking insects, ants, cockroaches, crickets, flies, and mosquitoes, and may be used for control of these in agricultural or (as Baygon) in non-agricultural (e.g. private or public facilities and grounds) applications. Agricultural applications include cane, cocoa, fruit, grapes, maize, rice, sugar, vegetables, cotton, lucerne, forestry, and ornamentals. It has contact and stomach action that is long-acting when it is in direct contact with the target pest. Propoxur is available in several types of formulations and products, including emulsifiable concentrates, wettable powders, baits, aerosols, fumigants, granules, and oilsprays.

Formulation: Propoxur is available in several types of formulations and products, including emulsifiable concentrates, wettable powders, baits, aerosols, fumigants, granules, and oilsprays. Toxicological Effects:

• Acute toxicity: Propoxur is highly toxic via the oral route, with reported LD50 values of approximately 100 mg/kg in rats and mice [10]. An oral LD50 of 40 mg/kg is reported for guinea pigs [5]. Propoxur is only slightly toxic via the dermal route, with reported dermal LD50 values of 1000 mg/kg to greater than 2400 mg/kg in rats, and greater than 500 mg/kg in rabbits [5]. Tests show that propoxur does not cause skin or eye irritation in rabbits [10]. Via the inhalation route, it is also slightly toxic, with a reported 1-hour inhalation LC50 of greater than 1.44 mg/L [10]. Like other carbamates, propoxur can inhibit the action of cholinesterase and disrupt nervous system function. Depending on the severity of exposure, this effect may be short-term and reversible [5]. Signs of propoxur intoxication can include nausea, vomiting, abdominal cramps, sweating, diarrhea, excessive, salivation, weakness, imbalance, blurring of vision, breathing difficulty, increased blood pressure, incontinence, or death [5]. In rats, propoxur poisoning resulted in brain pattern and learning ability changes at lower concentrations than those which caused cholinesterase-inhibition and/or organ weight changes [8]. During wide-scale spraying of propoxur in malarial control activities conducted by the World Health Organization (WHO), only mild cases of poisoning were noted. Applicators who used propoxur regularly showed a pronounced daily fall in whole blood cholinesterase activity and a distinct recovery after exposure stopped. No adverse cumulative effects on cholinesterase activity were demonstrated [8]. Human adults have ingested single doses of 50 mg of propoxur without apparent symptoms [5].
• Chronic toxicity: Prolonged or repeated exposure to propoxur may cause symptoms similar to acute effects. Propoxur is very efficiently detoxified (transformed into less toxic or practically nontoxic forms), thus making it possible for rats to tolerate daily doses approximately equal to the LD50 of the insecticide for long periods, provided that the dose is spread out over the entire day, rather than ingested all at once [5].
• Reproductive effects: In female rats given high dietary doses of approximately 18 mg/kg/day of propoxur as a part of a three-generation reproduction study, reduced parental food consumption, growth, lactation, and litter size were observed [5]. At 25 mg/kg/day administered to pregnant rats there was a decrease in the number of offspring [5]. Dietary doses of approximately 2.25 mg/kg/day did not affect fertility, litter size, or lactation, but parental food intake and growth were depressed in the exposed group [5]. This evidence suggest that reproductive effects in humans are unlikely at expected exposure levels.
• Teratogenic effects: Offspring of female rats fed 5 mg/kg/day of propoxur during gestation and weaning exhibited reduced birth weight, retarded development of some reflexes, and evidence of central nervous system impairment [5]. In another rat study, growth reduction was observed in the offspring of pregnant rats given doses of 3, 9 and 30 mg/kg/day, but no other physiological or anatomical abnormalities were observed. The evidence suggests that teratogenic effects will only occur at high doses.
• Mutagenic effects: Propoxur did not cause mutations in six different types of bacteria [46]. The evidence indicates that propoxur is not mutagenic.
• Carcinogenic effects: No carcinogenic effects have been reported for propoxur [5].
• Organ toxicity: As determined in animal tests and data from human autopsies in poisoned individuals, the nervous system, and liver are the organs principally affected by propoxur [5,46].

• Fate in humans and animals: Propoxur is broken down and excreted rapidly in urine [5]. In humans given a single oral dose of 92.2 mg of Baygon, 38% of the dose was excreted in urine over the first 24 hours, with most of it excreted in the first 8 to 10 hours [5]. Carbamates generally are excreted rapidly and do not accumulate in mammalian tissue [5].

Ecological Effects:

• Effects on birds: Propoxur is very highly to highly toxic to many bird species, but its toxicity varies by the species. The reported LD50 is 25.9 mg/kg in bobwhite quail [10]. Other reported oral LD50 values (for a 97 to 98% technical grade propoxur product), are 4 mg/kg in mourning doves and house finches, 6 mg/kg in Canada geese, 10.5 mg/kg in mallards, 20 mg/kg in pheasants, 26 mg/kg and 28 mg/kg in California and Japanese quail respectively and 120 mg/kg in grouse [17]. The 5-day dietary LC50 for Japanese quail is greater than 5000 ppm [10]. Acute symptoms of propoxur poisoning in birds include eye tearing, salivation, muscle incoordination, diarrhea, and trembling [47]. Depending on the type of bird, poisoning signs can appear within 5 minutes of exposure, with deaths occurring between 5 and 45 minutes, or overnight. Symptoms in survivors disappeared from 90 minutes to several days after treatment [47].

• Effects on aquatic organisms: Propoxur is moderately to slightly toxic to fish and other aquatic species. The reported 96-hour LC50 values are 3.7 mg/L in rainbow trout, and 6.6 mg/L in bluegill sunfish [10]. The oral LD50 for propoxur in bullfrogs is 595 mg/kg [17]. The compound is not expected to accumulate significantly in aquatic organisms. The calculated accumulation factor for propoxur is nine times the ambient water concentration.
• Effects on other organisms: Propoxur is highly toxic to honeybees [10]. The oral LD50 for propoxur in mule deer is 100 to 350 mg/kg [17].

Environmental Fate:

• Breakdown in soil and groundwater: Propoxur is of moderate to low persistence in the soil environment, with reported field half-lives of 14 to 50 days [13]. It has a low affinity for soil binding, and so may be mobile in many soils [13]. Because it is highly soluble in water, is moderately persistent, and does not adsorb strongly to soil particles, propoxur has a high potential for groundwater penetration [14,48]. In one study, there was practically no loss of propoxur from a silt-loam soil to which it was applied during a 6-month period, but 25% of applied Baygon was lost from sand in 100 days [48]. In another study, propoxur was very mobile in sandy loam, silt loam and silty clay soils. The rate of biodegradation in soil increases in soils that have been previously exposed to propoxur or other methylcarbamate pesticides [48].
• Breakdown in water: Propoxur hydrolyzes, or breaks down in water, at a rate of 1.5% per day in a 1% aqueous solution at pH of 7.0 [48].
• Breakdown in vegetation: Propoxur can enter the roots of a plant and travel to the leaves, where it can then poison insects that feed on the leaves, and can have residual activity of up to 1 month when applied to plant surfaces [8].

Physical Properties:

• Appearance: Technical propoxur is a white to cream-colored crystalline solid.
• Chemical Name: 2-isopropoxyphenyl methylcarbamate [10]
• CAS Number: 114-26-1
• Molecular Weight: 209.25
• Water Solubility: 2000 mg/L @ 20 C [10]
• Solubility in Other Solvents: Soluble in most polar organic solvents, e.g, acetone, methanol, cyclohexanone, chloroform, and toluene [10]
• Melting Point: 84-87 C [10]
• Vapor Pressure: 300 mPa @ 120 C [10]
• Partition Coefficient: 0.14 [48]
• Adsorption Coefficient: 30 [13]

Exposure Guidelines:

• ADI: 0.02 mg/kg/day [10]
• MCL: Not Available
• RfD: Not Available
• PEL: 0.5 mg/m3 (8-hour) [31]
• HA: 0.003 mg/L [48]
• TLV: Not Available

Basic Manufacturer:

Atomergic Chemetals Corp.
222 Sherwood Avenue
Farmingdale, NY 11735-1718

• Phone: 516-694-9000
• Emergency: 800-424-9300
  

References:

References for the information in this PIP can be found in Reference List Number 3

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.