Coumaphos (ISO)

Pesticides

Insecticides

Active substance -> EU Pesticides database: Not approved

Pesticides -> Organophosphate Insecticides

Pesticide (Coumaphos) -> USDA PDB

log Kow = 4.13

4.13

4.01

1.31 at 77 °F (EPA, 1998) - Denser than water; will sink

1.474 g/cu cm

1.47 g/cm³

1.31

1.47 @ 20°C

less than 1 mg/mL at 72 °F (NTP, 1992)

In water, 1.5 mg/L at 20 °C

Limited solubility in organic solvents

Somewhat soluble in acetone, chloroform, corn oil

At 20 °C, soluble in acetone (23.82 g/100 mL) and diethyl phthalate (21.50 g/100 mL); much less soluble in denatured alcohol and xylene (0.9 g/100 mL in each); only slightly soluble in octanol (0.13 g/100 mL), hexane (0.07 g/100 mL), and mineral spirits (0.09 g/100 mL)

Solubility in water: none

68 °F at 1e-07 mmHg (NTP, 1992)

68 °F at 1x10-7 mmHg

196 °F (EPA, 1998)

95.2 °C

MP: 90-92 °C (technical coumaphos)

91 °C

196 °F

95 °C

Danger

H300: Fatal if swallowed [Danger Acute toxicity, oral]

P264, P270, P273, P280, P301+P316, P302+P352, P317, P321, P330, P362+P364, P391, P405, and P501 (click each P-code to see the statement)

Danger

H300 (100%): Fatal if swallowed [Danger Acute toxicity, oral]

P262, P264, P270, P273, P280, P301+P316, P302+P352, P316, P317, P321, P330, P361+P364, P362+P364, P391, P405, and P501 (click each P-code to see the statement)

Hazard Traits - Developmental Toxicity; Environmental tox; Neurotoxicity

Coumaphos is listed in the dataset of EPA Human Health Benchmarks for Pesticides under the Safe Drinking Water Act (40 eCFR 141)

Coumaphos: HSNO Approval: HSR002829 Approved with controls

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

When heated to decomposition, it emits very toxic fumes of sulfur oxides, phosphorus oxides, and chlorides. Incompatible with piperonyl butoxide. Stable in water. (EPA, 1998)

Not combustible. Liquid formulations containing organic solvents may be flammable. Gives off irritating or toxic fumes (or gases) in a fire. Heating will cause rise in pressure with risk of bursting.

The average of two baseline respective cholinesterase activity determinations three days apart, with no exposures to enzyme inhibiting pesticides for at least 30 days, is recommended for each worker prior to exposure to cholinesterase inhibitors because of large inter-individual differences in published baseline values. To be established at least once a year. Removal from workplace exposures is recommended until the cholinesterase activity returns to within 20% of baseline. [TLVs and BEIs]

Conditions of use: beef and dairy cattle ... Indications for use: Control of gastrointestinal roundworms (Haemonchus spp., Ostertagia spp., Cooperia spp., Nematodirus spp., Trichostrongylus spp.).

Conditions of use: Laying chickens ... Indications for use: For control of capillary worm (Capillaria obsignata) and as an aid in control of common round worm (Ascaridia galli) and cecal worm (Heterakis gallinae).

Conditions of use: replacement pullets ... Indications for use: For control of capillary worm (Capillaria obsignata) and as an aid in control of common roundworm (Ascaridia galli) and cecal worm (Heterakis gallinae).

USEPA/Office of Prevention, Pesticides and Toxic Substances; Reregistration Eligibility Decision Document - Coumaphos EPA 738-R-96-014 (August 1996). The RED summarizes the risk assessment conclusions and outlines any risk reduction measures necessary for the pesticide to continue to be registered in the U.S.[Available from, as of June 5, 2014: http://www.epa.gov/pesticides/reregistration/status.htm]

USEPA/Office of Prevention, Pesticides and Toxic Substances; Reregistration Eligibility Decision Addendum and FQPA Tolerance Reassessment Progress Report for Coumaphos EPA 738-R-00-010 (September 2000).[Available from, as of June 5, 2014: http://www.epa.gov/pesticides/reregistration/status.htm]

USEPA/Office of Prevention, Pesticides and Toxic Substances; Reregistration Eligibility Decision Document - Coumaphos (July 2006).[Available from, as of June 5, 2014: http://www.epa.gov/pesticides/reregistration/status.htm]

Bioassay of Coumaphos for Possible Carcinogenicity (1979) Technical Rpt Series No. 96 DHEW Pub No. (NIH) 79-1346, U.S. Department of Health Education and Welfare, National Cancer Institute, Bethesda, MD 20014

Use organic vapor respirator, rubber gloves, and goggles. Dike fire control water for disposal later.

In case of fire in the surroundings, use appropriate extinguishing media. In case of fire: keep drums, etc., cool by spraying with water.

Fresh air, rest. Artificial respiration may be needed. No mouth-to-mouth artificial respiration. Refer immediately for medical attention.

Remove contaminated clothes. Rinse and then wash skin with water and soap. Refer for medical attention .

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Give a slurry of activated charcoal in water to drink. NO mouth-to-mouth artificial respiration. Refer immediately for medical attention.

Biological Exposure Indices (BEI) [ACGIH] - Acetylcholinesterase activity in red blood cells = 70% of individual's baseline; Butylcholinesterase activity in serum or plasma = 60% of individual's baseline; Sample at end of shift; [TLVs and BEIs]

Hydrolysis: This cmpd can be decomposed on heating with concentrated alkali. It is oxidized with nitric acid or other oxidizing agents to the phosphate analogue, coroxon. Dilute alkali (pH 8-12) causes an opening of the pyrone ring, which can be closed again by acidification to yield the original compound.

Approximately 400 000 litres of cattle dip wastes containing approximately 1500 mg/L of the organophosphate insecticide coumaphos are generated yearly along the Mexican border from a USDA program designed to control disease-carrying cattle ticks. Use of unlined evaporation pits for the disposal of these wastes has resulted in highly contaminated soils underlying these sites. Previous work has shown that microbial consortia present in selected dip wastes can be induced to mineralize coumaphos. Our results demonstrate that similar microbial consortia are present in coumaphos-contaminated soils from eight waste sites and that these organisms are capable of mineralizing coumaphos in these soils using soil slurries to less than 1 mg/L in 7-10 days at 28 °C. In addition, our results show that these consortia are able to colonize pea gravel in trickling gravel filters and can be used in these filters to metabolize coumaphos from dip wastes to less than 0.1 mg/L in 7-10 days at 28 °C. These simple systems offer potential low cost means to detoxify coumaphos-containing wastes and to bioremediate soils contaminated with this organophosphate compound.

Insecticide wastes generated from livestock dipping operations are well suited for biodegradation processes since these wastes are concentrated, contained, and have no other significant toxic components. A field-scale biofilter capable of treating 15,000-litre batches of dip waste containing the acaricide coumaphos was used to reduce the coumaphos concentration in two successive 11,000-litre batch trials from 2000 mg litre-1 to 10 mg/L in approximately 14 days at 25-29 °C. Removal of coumaphos from the biofilter effluent is a function of both physical filtration and biodegradation by the biofilter. However, stoichiometric increases in chloride levels in the effluent as coumaphos concentrations decreased confirmed that coumaphos was being degraded by the biofilter rather than just being filtered out. In subsequent 5,500-litre batch experiments, the addition of a vitamin supplement to the biofilter-treated dip resulted in a further decrease in coumaphos concentration to approximately 1 mg/L. Results from incubations of two representative Texas soils with biofilter-treated dip spiked with (benzo-U-14C) coumaphos revealed that 32-36% of the spiked (14C) coumaphos was mineralized in the soils after 110 days at 30 °C.

Accidental Release Measures. Personal precautions, protective equipment and emergency procedures: Wear respiratory protection. Avoid dust formation. Avoid breathing vapours, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided. Methods and materials for containment and cleaning up: Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance and protective clothing. Do NOT wash away into sewer. Collect the spilled substance into containers. If appropriate, moisten first to prevent dusting. Then store and dispose of according to local regulations.

Notify local health and wildlife officials and operators of nearby water intakes /if spilled into water/.

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.

If the compound has been ingested, rapid gastric lavage should be performed using 5% sodium bicarbonate. For skin contact, the skin should be washed with soap and water. If the compound has entered the eyes, they should be washed with large quantities of isotonic saline or water. In serious cases, atropine and/or pralidoxime should be administered. Anti-cholinergic drugs work to counteract the effects of excess acetylcholine and reactivate AChE. Atropine can be used as an antidote in conjunction with pralidoxime or other pyridinium oximes (such as trimedoxime or obidoxime), though the use of '-oximes' has been found to be of no benefit, or possibly harmful, in at least two meta-analyses. Atropine is a muscarinic antagonist, and thus blocks the action of acetylcholine peripherally.

Acute exposure to cholinesterase inhibitors can cause a cholinergic crisis characterized by severe nausea/vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved. Accumulation of ACh at motor nerves causes overstimulation of nicotinic expression at the neuromuscular junction. When this occurs symptoms such as muscle weakness, fatigue, muscle cramps, fasciculation, and paralysis can be seen. When there is an accumulation of ACh at autonomic ganglia this causes overstimulation of nicotinic expression in the sympathetic system. Symptoms associated with this are hypertension, and hypoglycemia. Overstimulation of nicotinic acetylcholine receptors in the central nervous system, due to accumulation of ACh, results in anxiety, headache, convulsions, ataxia, depression of respiration and circulation, tremor, general weakness, and potentially coma. When there is expression of muscarinic overstimulation due to excess acetylcholine at muscarinic acetylcholine receptors symptoms of visual disturbances, tightness in chest, wheezing due to bronchoconstriction, increased bronchial secretions, increased salivation, lacrimation, sweating, peristalsis, and urination can occur. Certain reproductive effects in fertility, growth, and development for males and females have been linked specifically to organophosphate pesticide exposure. Most of the research on reproductive effects has been conducted on farmers working with pesticides and insecticdes in rural areas. In females menstrual cycle disturbances, longer pregnancies, spontaneous abortions, stillbirths, and some developmental effects in offspring have been linked to organophosphate pesticide exposure. Prenatal exposure has been linked to impaired fetal growth and development. Neurotoxic effects have also been linked to poisoning with OP pesticides causing four neurotoxic effects in humans: cholinergic syndrome, intermediate syndrome, organophosphate-induced delayed polyneuropathy (OPIDP), and chronic organophosphate-induced neuropsychiatric disorder (COPIND). These syndromes result after acute and chronic exposure to OP pesticides.

LD50; Species: /Anas platyrhynchos/ (Mallard) male age 3-4 months; oral 29.8 mg/kg (95% confidence limit 21.5-41.3 mg/kg) /purity: 95%/

LC50; Species: Anas platyrhynchos (Mallard Duck) chemical incorporated into food 401 ppm for 8 days (95% confidence interval: 277-592.71 ppm)

LC50; Species: Colinus virginianus (Northern Bobwhite Quail) chemical incorporated into food 85 ppm for 8 days (95% confidence interval: 70-102 ppm)

LD50; Species: Colinus virginianus (Northern Bobwhite Quail) oral via capsule 2.36 mg/kg (95% confidence interval: 1.12-3.26 mg/kg)

For more Ecotoxicity Values (Complete) data for COUMAPHOS (28 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values of 5778 to 21,120(2), indicate that coumaphos is expected to be immobile in soil(SRC). Volatilization of coumaphos from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 3.1X10-8 atm-cu m/mole(SRC), based upon its vapor pressure, 9.7X10-8 mm Hg(2), and water solubility, 1.5 mg/L(2). Coumaphos is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(2). Half-lives of approximately 300 days in a sandy loam soil and 200 days in a silty loam soil were observed; the major degradation products were chlorferon (3-chloro-4-methyl-7-hydroxycoumarin) and the oxygen analog(3). No degradation of coumaphos was noted in a microbially-active Drummer silty clay loam soil in 22 days(3). Coumaphos was degraded in 7 days in soil slurries using soil from six cattle dip vat waste disposal pits in Texas(4). In similar experiments using (14)C ring-labeled coumaphos, 61% of the (14)C was recovered as (14)CO2 when radio-labeled coumaphos was added to soil slurries containing 1200 mg/L coumaphos; no loss of coumaphos nor production of (14)CO2 was observed when sodium azide was added to the soil slurries(4). The photolysis half-life of coumaphos on a soil surface was reported to be 23.8 days(2).

AQUATIC FATE: Based on a classification scheme(1), Koc values of 5778 to 21,120(2), indicate that coumaphos is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 3.1X10-8 atm-cu m/mole(SRC), derived from its vapor pressure, 9.7X10-8 mm Hg(2), and water solubility, 1.5 mg/L(2). According to a classification scheme(4), BCFs of 110(5) and 540(6), suggest bioconcentration in aquatic organisms is high(SRC). In a biodegradability screening test using an activated sludge inoculum and 50 ug/L of radio-labeled test compound, 0.9% of coumaphos was mineralized in 5 days(5). Half-lives of coumaphos in sunlit river water and seawater were 5 and 8 days, respectively(7). The half-life of coumaphos in buffered aqueous solution was 23 days at pH 9 and 50 °C, while in pH 5.5 pond water at temperatures ranging from 20-35 °C, it was <7 days(8).

AQUATIC FATE: The half-life of coumaphos in Limon River (Venezuela) water under 4 different conditions was 25.21, 9.71, 7.31 and 4.96 days in dark filtered, sunlit filtered, open non-filtered and closed non-filtered water, respectively(1).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), coumaphos, which has a vapor pressure of 9.7X10-8 mm Hg at 25 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase coumaphos is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and ozone(SRC); the half-lives for these reactions in air are estimated to be 3.4 and 14 hours, respectively(3). Particulate-phase coumaphos may be removed from the air by wet and dry deposition(SRC). Coumaphos absorbed on silica gel mineralized 6.9% when exposed to light >290 nm(4) and, therefore, may be susceptible to direct photolysis by sunlight(SRC).

Coumaphos was detected in 24 of 69 honey samples collected in northwest Spain in 1989 and 1990, concentrations ranged from 1 to 53 ug/kg, mean 6.0 ug/kg; coumaphos was detected in 8 samples of honey in 1991(1,2). Honey from hives treated with 0.032 g active ingredient coumaphos had 54, 45, 48, 26, 20 and 14 ug/kg coumaphos after 0, 1, 3, 7, 15 and 21 days, respectively(3). Coumaphos was not detected in canned peaches from the 1999 season or from fresh peaches sampled Aug 2000; 210 samples were collected in Imathia and Pella, Greece(4). Coumaphos was not detected in green beans, sweet potatoes, spinach, tomatoes, strawberries, peaches or pears; sample dates, locations and detection limits were not reported(5).

Coumaphos was reported in honey samples from various European countries. It was not detected (detection limit 1.60 ng/g) in 275 honey samples collected in 2004 from 33 locations throughout Turkey(1).[Table#932]

EXPERIMENTAL: In trials in the Netherlands, cows were treated at a rate of 1.5 g/cow (50% wp) 2 times at 8 day intervals. Mean residues (mg/kg) present in milk at various intervals were: 6 hr, 0.25 mg/kg; 18 hr, 0.21 mg/kg; 30 hr, 0.13 mg/kg; and 42 hr, less than 0.1 mg/kg. The maximum residue limits for various dairy products currently in force in Australia and those under consideration in The Netherlands are reported. It is recommended that a maximum residue of 0.02 mg/kg (sum of coumaphos and its oxygen analogs) be established.

EXPERIMENTAL: After dermal application of a 0.75% emulsion of radiolabeled coumaphos on a cow, at 40 mg/kg body weight, the concentration of the chemical in the milk rose rapidly to approximately 60 ppb and then declined rapidly to less than 5 ppb in 3 days(1). Similar behavior was observed when coumaphos was applied on a goat(1).

IDENTIFICATION AND USE: Coumaphos is an organophosphate insecticide used for control of a wide variety of insects on cattle and parasitic mites (Varroa jacobson) on bees. It is also used in veterinary medicine for the treatment of screwworms, maggots, and ear ticks on livestock. Registered for use in the U.S., but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses. HUMAN EXPOSURE AND TOXICITY: The signs and symptoms of a human exposure to coumaphos are similar to general exposure to organophosphates: potent cholinesterase enzyme inhibitors that act by interfering with the metabolism of acetylcholine, which results in accumulation of acetylcholine at neuroreceptor transmission sites. Exposure produces a broad spectrum of clinical effects indicative of massive overstimulation of the chlorinergic system, including muscarinic effects (parasympathetic), nicotinic effects (sympathetic and motor), and CNS effects. These effects present clinically as feeling of headache, weakness, dizziness, blurred vision, psychosis, respiratory difficulty, paralysis, convulsions, and coma. According to case reports, human exposure can occur due to accidental ingestion from contaminated food, intentional ingestion or inhalation. ANIMAL STUDIES: Dermal administration of single (50-500 mg/kg) or daily (100 mg/kg) doses of coumaphos resulted in delayed neurotoxicity in hens. Coumaphos caused loss of weight and produced ataxia, which progressed to paralysis and death. Some hens given a single oral 50 mg/kg dose or daily 5 mg/kg doses of coumaphos recovered from the initial cholinergic effect and developed clinical signs of delayed neurotoxicity. A bioassay of coumaphos for possible carcinogenicity was conducted by administering the test chemical in feed to rats and mice. In both rats and mice, no tumors occurred in the dosed groups of either sex at incidences that were significantly higher than those in corresponding control groups. Weekly spraying at concentration of 200-400 ppm or weekly dipping in solution containing 200 ppm for 2 year period had no adverse effect on cattle. ECOTOXICITY STUDIES: In water fowl exposed to coumaphos, signs appeared as soon as 40 min in mallard ducks and 90 min in pheasants and mortalities usually occurred between 2 and 3 hour after treatment. Recovery took up to 14 days.

Coumaphos is a cholinesterase or acetylcholinesterase (AChE) inhibitor. A cholinesterase inhibitor (or 'anticholinesterase') suppresses the action of acetylcholinesterase. Because of its essential function, chemicals that interfere with the action of acetylcholinesterase are potent neurotoxins, causing excessive salivation and eye-watering in low doses, followed by muscle spasms and ultimately death. Nerve gases and many substances used in insecticides have been shown to act by binding a serine in the active site of acetylcholine esterase, inhibiting the enzyme completely. Acetylcholine esterase breaks down the neurotransmitter acetylcholine, which is released at nerve and muscle junctions, in order to allow the muscle or organ to relax. The result of acetylcholine esterase inhibition is that acetylcholine builds up and continues to act so that any nerve impulses are continually transmitted and muscle contractions do not stop. Among the most common acetylcholinesterase inhibitors are phosphorus-based compounds, which are designed to bind to the active site of the enzyme. The structural requirements are a phosphorus atom bearing two lipophilic groups, a leaving group (such as a halide or thiocyanate), and a terminal oxygen.

/BIRDS and MAMMALS/ A group of 50 birds (Coturnix) was fed coumaphos in the diet ranging in concentrations of 50, 84 and 239 ppm with corn oil as diluent. Mortality ranged from 1/10 in 4 days at 84 ppm and 4/10 birds in 6 days at 239 ppm. No deaths occurred at 50 ppm. Technical grade, 95% active ingredient was used.

/BIRDS and MAMMALS/ Signs of intoxication: /mallards and pheasants, acute oral, dosage range: 5.73 to 41.3 mg/kg; 95% purity/ spraddle-legged walking, wing twitching, slowness, hypoactivity, ataxia, wing-drop, falling, mutation, prostration with wings spread, lacrimation, immobility, wing-beat convulsions, and tetany. Signs appeared as soon as 40 min in mallards and 90 min in pheasants and mortalities usually occurred between 2 and 3 hr after treatment. Remission took up to 14 days.

Coumaphos was detected in 22 of 92 honeybee (Apis mellifera) samples from the district of Bologna, Italy at concentrations of 0.002 to 2.777 mg/kg; dead bee samples were collected in bags suspended under beehives (only worker bees were analyzed)(1).

Conditions of use: beef and dairy cattle ... Indications for use: Control of gastrointestinal roundworms (Haemonchus spp., Ostertagia spp., Cooperia spp., Nematodirus spp., Trichostrongylus spp.).

Conditions of use: Laying chickens ... Indications for use: For control of capillary worm (Capillaria obsignata) and as an aid in control of common round worm (Ascaridia galli) and cecal worm (Heterakis gallinae).

Conditions of use: replacement pullets ... Indications for use: For control of capillary worm (Capillaria obsignata) and as an aid in control of common roundworm (Ascaridia galli) and cecal worm (Heterakis gallinae).

Tolerances for residues of the insecticide coumaphos (O,O-diethyl O-3-chloro-4-methyl-2-oxo-2H-1-benzopyran-7-yl phosphorothioate and its oxygen analog (O,O-diethyl O-3-chloro-4-methyl-2-oxo-2H-1-benzopyran-7-yl phosphate) in or on food commodities as follows:[Table#931]

EPA has concluded, after completing its assessment of the cumulative risks associated with exposures to all of the OPs /including coumaphos/, that: (1) the pesticides covered by the IREDs that were pending the results of the OP cumulative assessment (listed in Attachment A) are indeed eligible for reregistration; and (2) the pesticide tolerances covered by the IREDs and TREDs that were pending the results of the OP cumulative assessment (listed in Attachment A) meet the safety standard under Section 408(b)(2) of the FFDCA. Thus, with regard to the OPs, EPA has fulfilled its obligations as to FFDCA tolerance reassessment and FIFRA reregistration, other than product-specific reregistration.

In the Coumaphos Reregistration Eligibility Decision (RED) of 1996, the Agency established that USDA-APHIS /United States Department of Agriculture-Animal and Plant Health Inspection Service/ uses of coumaphos were eligible for reregistration because the use of this insecticide is very important to the USDA-APHIS Cattle Fever Tick Eradication Program and the U.S economy. USDA estimated the economic significance of the use of coumaphos to be between $1-5 billion dollars per year. With this program, USDA-APHIS has helped in preventing the re-establishment of the cattle fever tick and its associated disease, piroplasmosis (babesiosis), into the United States. EPA also considered the cholinesterase monitoring program currently run by USDA-APHIS in making the USDA-APHIS uses eligible for reregistration. ... In the 1996 RED, the Agency deferred making a reregistration eligibility decision for coumaphos uses other than those to control cattle fever tick by USDA-APHIS until chemical-specific handler studies were submitted and reviewed. ... However, more recently, based on the small volume and declining trend in the use of coumaphos as a livestock and swine bedding animal treatments, the Agency determined the chemical-specific handler exposure studies were not needed. The Agency has completed its assessment of the occupational risk associated with the use of pesticides containing the active ingredient coumaphos, as well as a coumaphos-specific dietary risk assessment. However, the Agency has not yet considered the cumulative effects of organophosphates as a class. Based on a review of surrogate handler exposure data submitted by the technical registrant, dietary and handler exposure data available to the Agency and public comments on the Agency's assessments for the active ingredient coumaphos, EPA has sufficient information on the human health effects of coumaphos to make a determination of reregistration eligibility for the non-USDA uses and to make some decisions as part of the tolerance reassessment process under FQPA. Although the Agency has not yet completed its cumulative risk assessment for the organophosphates, the Agency is issuing this assessment now in order to identity risk reduction measures that are necessary to allow the continued use of coumaphos. ... EPA has determined that certain uses of coumaphos, unless amended as set forth in this document, present risks inconsistent with FIFRA. Accordingly, EPA may commence a full risk/benefit analysis, the outcome of which may indicate that cancellation proceedings are warranted, unless registrants agree to label changes implementing the risk reduction measures discussed in this reregistration decision. At the time that a cumulative assessment is conducted, the Agency will address any outstanding risk concerns. ... Since the Agency has not yet completed the cumulative risk assessment for the organophosphates, this reregistration eligibility decision does not fully satisfy the reassessment of the existing coumaphos food residue tolerances as called for by the Food Quality Protection Act (FQPA). When the Agency has completed the cumulative assessment, coumaphos tolerances will be reassessed in that light. At that time, the Agency will reassess coumaphos along with the other organophosphate pesticides to complete the FQPA requirements and make a final reregistration determination.

The Agency has determined that coumaphos products, labeled and used as specified in this Reregistration Eligibility Decision, may pose adverse effects to humans, aquatic invertebrates and birds. The Agency has concerns with low MOEs /margin of exposure/ for mixer/loader/applicators, with the proper disposal of the spent cattle dip vat solutions, and with the acute toxicity of coumaphos to aquatic invertebrates and birds. The Agency defers making a regulatory decision on non-USDA uses of coumaphos until chemical-specific handler exposure studies are submitted (see Section V). The Agency can make a regulatory decision concerning the USDA uses of coumaphos because of the very significant economic benefits, the lack of an acceptable alternative, and the fact that USDA has a program in place to monitor the cholinesterase levels of the handlers involved. In the USDA Import program livestock are treated with coumaphos to control ticks and prevent outbreaks of Texas Cattle Fever (also known as Southern Fever). Coumaphos is also used in a quarantine mode. Together these uses account for almost half of coumaphos usage in the U.S. Despite uncertainties in the existing handler exposure databases, the Agency finds that MOEs for large dip vat and hand-held sprayer treatment of large herds are very low. Therefore, the Agency is requiring closed systems for the mixing/loading of coumaphos products used in dip vats and/or hand-held sprayers, i.e., water-soluble bags for the WP formulation. The registrant must determine an appropriate system to reduce handler exposure during mixing/loading for the flowable and emulsifiable concentrate formulations. The appropriate system to reduce handler exposure during mixing/loading may be gel packs, "no glug" containers or any other equivalent system approved by the Agency. Appropriate systems to reduce handler exposure must be addressed in the eight-month required response. The registrant must propose a system and submit handler exposure studies to document handler exposure and confirm that improved packaging/closed system now results in acceptable MOEs (specified in Part V). When the chemical-specific exposure data required by this RED are received and reviewed, the Agency will make a regulatory decision regarding the reregistration eligibility of the non-USDA uses of coumaphos. The Agency may reassess the USDA uses of coumaphos if the exposure data required as part of this RED (considered confirmatory when closed systems are introduced) indicates a high risk to handlers.

As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their continued use. Under this pesticide reregistration program, EPA examines newer health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether the use of the pesticide does not pose unreasonable risk in accordance to newer safety standards, such as those described in the Food Quality Protection Act of 1996. Coumaphos is found on List A, which contains most pesticides that are used on foods and, hence, have a high potential for human exposure. List A consists of the 194 chemical cases (or 350 individual active ingredients) for which EPA issued registration standards prior to FIFRA '88. Case No: 0018; Pesticide type: Insecticide; Registration Standard Date: 09/12/89; Case Status: RED Approved 09/96; OPP has made a decision that some/all uses of the pesticide are eligible for reregistration, as reflected in a Reregistration Eligibility Decision (RED) document.; Active ingredient (AI): coumaphos; Data Call-in (DCI) Date(s): 08/01/96; AI Status: OPP has completed a Reregistration Eligibility Decision (RED) document for the case/AI.

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 10 lb or 4.54 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV.D.3.b).

Releases of CERCLA hazardous substances are subject to the release reporting requirement of CERCLA section 103, codified at 40 CFR part 302, in addition to the requirements of 40 CFR part 355. Coumaphos is an extremely hazardous substance (EHS) subject to reporting requirements when stored in amounts in excess of its threshold planning quantity (TPQ) of 100 or 10,000 lbs. Extremely hazardous substances that are solids are subject to either of two threshold planning quantities ... The lower quantity applies only if the solid exists in powdered form and has a particle size less than 100 microns; or is handled in solution or in molten form; or meets the criteria for a National Fire Protection Association (NFPA) rating of 2, 3 or 4 for reactivity. If the solid does not meet any of these criteria, it is subject to the upper ... threshold planning quantity ... .

Coumaphos is designated as a hazardous substance under section 311(b)(2)(A) of the Federal Water Pollution Control Act and further regulated by the Clean Water Act Amendments of 1977 and 1978. These regulations apply to discharges of this substance. This designation includes any isomers and hydrates, as well as any solutions and mixtures containing this substance.

Larvae of cattle tick (Boophilus microplus) metabolized coumaphos to oxygen analog (coroxon), diethyl phosphate, and diethyl phosphorothioate.

Cattle tick Boophilus microplus was exposed to labeled coumaphos. ... UV and IR spectroscopy and chromatography were used to show the presence of unchanged coumaphos, oxygen analog, ethyl phosphate, ethyl phosphorothioate, orthophosphate, desethyl analogs, and an unknown metabolite.

(32)P ... coumaphos was applied dermally to a cow and a goat. Unextractable residues were significant in tissues of both animals. Most of the radioactivity appearing in the urine was as hydrolysis products. Some of oxygen deriv of coumaphos was found in initial (up to 6 hr) collections, but thereafter, hydrolysis products were predominant: 35% phosphoric acid, 17% diethyl phosphoric acid, 29% diethyl phosphorothioic acid and 18% as the the de-ethylated coumaphos and as oxygen analog, primarily.

In vitro studies with house fly and cattle grub ... homogenates have shown that coumaphos is activated to a cholinesterase inhibitor, presumably to oxygen analog but no degradation occurs. ... These findings are consistent with selective toxicity of coumaphos.

For more Metabolism/Metabolites (Complete) data for COUMAPHOS (9 total), please visit the HSDB record page.

Metabolism of organophosphates occurs principally by oxidation, by hydrolysis via esterases and by reaction with glutathione. Demethylation and glucuronidation may also occur. Oxidation of organophosphorus pesticides may result in moderately toxic products. In general, phosphorothioates are not directly toxic but require oxidative metabolism to the proximal toxin. The glutathione transferase reactions produce products that are, in most cases, of low toxicity. Paraoxonase (PON1) is a key enzyme in the metabolism of organophosphates. PON1 can inactivate some organophosphates through hydrolysis. PON1 hydrolyzes the active metabolites in several organophosphates insecticides as well as, nerve agents such as soman, sarin, and VX. The presence of PON1 polymorphisms causes there to be different enzyme levels and catalytic efficiency of this esterase, which in turn suggests that different individuals may be more susceptible to the toxic effect of organophosphate exposure.

Agents that kill parasitic worms. They are used therapeutically in the treatment of HELMINTHIASIS in man and animal.

Substances used in the treatment or control of nematode infestations. They are used also in veterinary practice.

Drugs that inhibit cholinesterases. The neurotransmitter ACETYLCHOLINE is rapidly hydrolyzed, and thereby inactivated, by cholinesterases. When cholinesterases are inhibited, the action of endogenously released acetylcholine at cholinergic synapses is potentiated. Cholinesterase inhibitors are widely used clinically for their potentiation of cholinergic inputs to the gastrointestinal tract and urinary bladder, the eye, and skeletal muscles; they are also used for their effects on the heart and the central nervous system.

Pesticides designed to control insects that are harmful to man. The insects may be directly harmful, as those acting as disease vectors, or indirectly harmful, as destroyers of crops, food products, or textile fabrics.

... Rats treated orally eliminated 70% of the applied dose in 7 days compared to about 5% after dermal treatment. ... Tissues from animals treated with coumaphos have been shown to contain largely degradation products.

When Rhode island hens were fed mash containing labeled coumaphos, considerably more radioactive material appeared in yolk than ... white or shell of eggs. Peak of radioactivity in eggs appeared 11-15 days after beginning of treatment and was present ... 6-8 days after return to normal diets.

Albino Wistar rats were given (14)C-labeled chlorferron, a metabolite of the ectoparasiticide coumaphos, in a a single dose of 20 mg/kg. In another experiment, a group of male rats were given single equimolar doses of either (14)C-labeled chlorferron (0.5 mg/kg) or (14)C-labeled coumaphos (0.86 mg/kg). Following both dose levels of chlorferron, more than 90% of the total (14)C admin was excreted in urine and feces during the first 24 hr. Fecal route of excretion was minor. The total urinary and fecal recoveries of (14)C after a period of 7 days following the admin of coumaphos were significantly lower at 79.1% chlorferron than at 93.7% chlorferron. Results indicate that chlorferron is not the end product of coumaphos metabolism in rats, and rapidly degrades to another metabolite.

Used for the control of a wide variety of livestock insects including cattle grubs, lice, scabies, flies, and ticks; the common ectoparasites of sheep, goats, horse, swine, and poultry as well as for screwworms in all these animals. [CAMEO] Used as an insecticide and ascaricide for direct application to cattle, goats, horses, sheep, and swine;

Farming (Pesticides) [Category: Industry]

For coumaphos (USEPA/OPP Pesticide Code: 036501) ACTIVE products with label matches. /SRP: Registered for use in the U.S. but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

Insecticide, acaricide

Non-systemic insecticide for control of Diptera, and for control of Hypoderma on cattle. Also controls parasitic mites (Varroa jacobson) on bees

THERAPEUTIC CATEGORY (VETERINARY): Anthelmintic, ectoparasiticide

The feed materials for coumaphos manufacture are diethyl phosphorothionochloridate and 3-chloro-4-methyl-7-hydroxy coumarin. ... The reaction is usually carried out in the presence of an acid binding agent such as potassium carbonate. This process is carried out at a reaction temp in the range of 50 deg to 100 °C. This reaction is carried out at atm pressure. Reaction periods of 15 min to several hr are used. This reaction is preferably carried out in the presence of a diluent in which the coumarin is soluble. Particularly suitable solvents of this kind are ketones such as acetone and methyl ethyl ketone.

Sprays, emulsifiable solution, wettable powder, pour-on.

Co-Ral Animal Insecticide 1% Shaker Can (Bayer HealthCare LLC): Active ingredient: coumaphos 1.0%.

Coumaphos Technical (Bayer HealthCare LLC): Active ingredient: coumaphos 97.0%.

Co-Ral (Coumaphos) Animal Insecticide 1% Bulk Dust (Bayer HealthCare LLC): Active ingredient: coumaphos 1.0%.

For more Formulations/Preparations (Complete) data for COUMAPHOS (18 total), please visit the HSDB record page.