クロルピリホス

Pesticide -> EPA IRIS

Acaricides, Insecticides

Active substance -> EU Pesticides database: Not approved

Pesticides -> Organophosphate Insecticides

Pesticide

Insecticides

log Kow = 4.96

4.96

4.96

4.77

1.4 (Liquid at 110 °F) (NIOSH, 2024) - Denser than water; will sink

1.44 at 20 °C

1.4 g/cm³

1.40 (liquid at 110 °F)

1.44 @ 20°C

1.40 (Liquid at 110 °F)

White granular crystals

Colorless crystals

Colorless to white crystalline solid [Note: Commercial formulations may be combined with combustible liquids.]

approximately 2 mg/L at 77 °F (NTP, 1992)

In water, 1.4 mg/L at 25 °C

In water, 1.12 mg/L at 24 °C

In water, 0.39 mg/L at 19.5 °C /OECD 105 method/

Solubility at 25 °C: isooctane 79% wt/wt; methanol 43% wt/wt

Solubility (g/100 g): acetone 650, benzene 790, carbon disulfide 590, carbon tetrachloride 310, chloroform 630, diethyl ether 510, ethanol 63, ethyl acetate >200, isooctane 79, kerosene 60, methanol 45, methylene chloride 400, propylene glycol 4, toluene 150, 1,1,1-trichloroethane 400, triethylene glycol 5, xylene 400. Readily soluble in other organic solvents.

82 °F (CLOSED CUP) /DURSBAN 4E/

87 °F (CLOSED CUP) /LORSBAN 4E/

320 °F at 760 mmHg (Decomposes) (NIOSH, 2024)

320 °F (decomp)

No boiling point at normal pressure; decomposes at 160 °C

320 °F (decomposes)

320 °F (Decomposes)

Decomposition temperature: approx 160 °C

160 °C. This produces toxic and corrosive fumes including hydrogen chloride, phosgene, phosphorus oxides, nitrogen oxides and sulfur oxides. Attacks copper and brass.

Danger

H301: Toxic if swallowed [Danger Acute toxicity, oral]

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

Danger

H301 (100%): Toxic if swallowed [Danger Acute toxicity, oral]

P260, P264, P264+P265, P270, P271, P273, P280, P284, P301+P316, P302+P352, P304+P340, P305+P351+P338, P316, P317, P320, P321, P330, P337+P317, P362+P364, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

Hazard Traits - Developmental Toxicity; Environmental tox; Neurotoxicity

Commission Regulation No 844/2012

05/72/EC, Reg. (EU) 2018/1796, Reg. (EU) 2020/18, Reg. (EU) 84/2018, Reg. (EU) No 540/2011, Reg. (EU) No 762/2013

Status: No longer Valid Update: 05-10-2020 https://echa.europa.eu/registration-dossier/-/registered-dossier/31753

Chlorpyrifos: HSNO Approval: HSR002942 Approval subject to a phase-out period

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.)

Excerpt from ERG Guide 152 [Substances - Toxic (Combustible)]:

Combustible. Gives off irritating or toxic fumes (or gases) in a fire. Liquid formulations containing organic solvents may be flammable. Risk of fire and explosion if formulations contain flammable/explosive solvents.

Symptoms of organophosphate insecticide poisoning: cholinesterase inhibition, headache, fatiguedizziness, blurred vision, weakness, nausea, cramps, diarrhea, chest discomfort, sweating, miosis, tearing, salivation, vomiting, cyanosis, papilledema, and muscle twitching. In advanced cases convulsions, coma, loss of reflexes, and loss of sphincter control may occur. EYES: Can produce mild to moderate eye irritation and transient corneal injury. SKIN: Undiluted liquid products can cause skin irritation. Prolonged or repeated exposure may cause superficial burns. (USCG, 1999)

Chlorpyrifos is an insecticide that is a white crystal-like solid with a strong odor. It does not mix well with water, so it is usually mixed with oily liquids before it is applied to crops or animals. It may also be applied to crops in a capsule form. Chlorpyrifos has been widely used in homes and on farms. In the home, it is used to control cockroaches, fleas, and termites; it is also used in some pet flea and tick collars. On the farm, it is used to control ticks on cattle and as a spray to control crop pests.

The EPA reentry interval is 24 hours for emulsifiable concentrate or wettable powder if workers are not wearing protective clothing. Chlorpyrifos is classified as moderately toxic. [EXTOXNET] A small number of the organophosphates (OPs) can Induce Delayed Neuropathy (OPIDN). OPIDN usually occurs after ingestion and is usually nonoccupational. [Levy, p. 431] 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]

DHHS/ATSDR; Toxicological Profile for Chlorpyrifos (September 1997). The ATSDR toxicological profile characterizes the toxicologic and adverse health effects information for the hazardous substance. Each peer-reviewed profile identifies and reviews the key literature that describes a hazardous substance's toxicologic properties. Other pertinent literature is also presented, but is described in less detail than the key studies.[Available from, as of November 19, 2007: http://www.atsdr.cdc.gov/toxprofiles/tp84.html]

FAO/WHO; Pesticide Residues in Food, Toxicological Evaluations, Chlorpyrifos (1999). Chlorpyrifos was reviewed at the Joint meeting of the FAO Panel of Experts on Pesticide Residues in Food and the Environment and the WHO Core Assessment Group in Rome, 20-29 September 1999, within the periodic review programme of the Codex Committee on Pesticide Residues.

USEPA; Ambient Water Quality Criteria Doc: Chlorpyrifos (1986) EPA 440/5-86-005

Nat'l Research Council Canada; Ecotoxicology of Chlorpyrifos (1978) NRCC No. 16079

USEPA/Office of Prevention, Pesticides and Toxic Substances; Interim Reregistration Eligibility Decision Document - Chlorpyrifos Case No. 0100 (September 2001)[Available from, as of June 5, 2014: http://www.epa.gov/pesticides/reregistration/status.htm]

Tolerances are established for residues of the pesticide chlorpyrifos per se (O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) in or on the following food commodities:[Table#1167]

A tolerance of 0.1 part per million is established for residues of chlorpyrifos, per se, in or on food commodities (other than those already covered by a higher tolerance as a result of use on growing crops) in food service establishments where food and food products are prepared and served, as a result of the application of chlorpyrifos in microencapsulated form.

Tolerances with regional registration, as defined in 180.1(l), are established for residues of the pesticide chlorpyrifos per se (O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) in or on the following food commodities:[Table#1168]

EPA has concluded, after completing its assessment of the cumulative risks associated with exposures to all of the OPs /including chlorpyrifos/, 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.

For more FIFRA Requirements (Complete) data for CHLORPYRIFOS (7 total), please visit the HSDB record page.

Excerpt from ERG Guide 152 [Substances - Toxic (Combustible)]:

Use water spray, foam, powder, carbon dioxide. In case of fire: keep drums, etc., cool by spraying with water.

Fresh air, rest. Refer immediately for medical attention.

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

Rinse with plenty of water (remove contact lenses if easily possible). Refer for medical attention.

Rinse mouth. Do NOT induce vomiting. Refer immediately for medical attention.

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

(General first aid procedures)

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]

If material is on fire or involved in a fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn, or burns with difficulty.) Keep runoff water out of sewers and water sources. /Other regulated substances, solid, NOS/

If material on fire or involved in fire: Use water in flooding quantities as fog. Extinguish fire using agent suitable for type of surrounding fire (Material itself does not burn or burns with difficulty.). Use foam, dry chemical, or carbon dioxide. /Organophosphorus pesticides, liquid, NOS/

If material on fire or involved in fire: Use water in flooding quantities as fog. Extinguish fire using agent suitable for type of surrounding fire (Material itself does not burn or burns with difficulty.). Use foam, dry chemical, or carbon dioxide. /Organophosphorus pesticides, solid, NOS/

Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

Do not contaminate water, food or feed by storage or disposal. Open dumping is prohibited. ... Store in original container in secured dry storage area. Prevent cross-contamination with other pesticides and fertilizers. Do not store above 1002F for extended periods of time. If container is damaged or spills occurs, use product immediately or dispose of product ... . /Dursban W/

... Chlorpyrifos must be stored to avoid contact with strong bases, or acids, or acid fumes since violent reaction can occur. Store in tightly closed containers in a cool, well ventilated area away from sources of heat.

Keep locked up. Keep away from food, drink and animal feeding stuffs.

Keep container tightly closed in a dry and well-ventilated place. Recommended storage temperature: 2 - 8 °C

Environmental considerations: land spill: Dig a pit, pond, lagoon, or holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Cover solids with a plastic sheet to prevent dissolving in rain or fire fighting water. Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. /Organophosphorus pesticides, solid, NOS/

Environmental considerations: land spill: Dig a pit, pond, lagoon, or holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./. Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. /Organophosphorus pesticides, liquid, NOS/

Environmental considerations: water spill: Use natural deep water pockets, excavated lagoons, or sand bag barriers to trap material at bottom. Remove trapped material with suction hoses. Use mechanical dredges or lifts to remove immobilized masses of pollutants and precipitates. /Other regulated substances, solid, NOS/

Environmental considerations: water spill: Use natural barriers or oil spill control booms to limit spill travel. Use natural deep water pockets, excavated lagoons, or sand bag barriers to trap material at bottom. Remove trapped material with suction hoses. /Organophosphorus pesticides, liquid and solid, NOS/

For more Cleanup Methods (Complete) data for CHLORPYRIFOS (6 total), please visit the HSDB record page.

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.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

This pesticide is toxic to birds and /other/ wildlife, and extremely toxic to fish and aquatic organisms. Do not discharge effluent containing this product into lakes, streams, ponds, estuaries, oceans, or other waters unless in accordance with the requirements of a National Pollutant Discharge Elimination System (NPDES) permit and the permitting authority has been notified in writing prior to discharge. Do not discharge effluent containing this product to sewer systems without previously notifying the local sewage treatment plant authority. For guidance, contact your State Water Board or Regional Office of the EPA. /Dursban W/

Pesticide Disposal: Wastes resulting from the use of this product may be disposed of on site or at an approved waste disposal facility. Container Disposal: Completely empty liner by shaking or tapping sides and bottom to loosen clinging particles. Empty residues into manufacturing equipment. Then dispose of liner in a sanitary landfill or by incineration, or, if allowed by state and local authorities, by burning. If container is contaminated and cannot be reused, dispose of in the same manner. /Dursban W/

For more Disposal Methods (Complete) data for CHLORPYRIFOS (6 total), please visit the HSDB record page.

Evacuate danger area! Consult an expert! Personal protection: chemical protection suit including self-contained breathing apparatus. Do NOT let this chemical enter the environment. Do NOT wash away into sewer. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Then store and dispose of according to local regulations.

Do not get in eyes or on clothing. Avoid contact with skin. Avoid breathing dust and spray mist. Wear protective clothing (long-sleeved shirt and long pants, waterproof gloves, and shoes plus socks). Wear protective eyewear and a respiratory protection device (MSHA/INIOSH approved number TC-21C) when mixing and loading or working in a non-ventilated space. Wash thoroughly with soap and water after handling and before eating, drinking, or using tobacco. Remove contamInated clothing and wash before reuse. Keep away from food, feedstuffs and water supplies. /Dursban W/

Avoid contact with skin, eyes, and clothing. Wash contaminated clothing before re-use. Avoid breathing dust, spray, or mist. Do not contaminate food or feed. /Data from table/

If material is not on fire and not involved in fire: Keep material out of water sources and sewers.

The worker should immediately wash the skin when it becomes contaminated.

For more Preventive Measures (Complete) data for CHLORPYRIFOS (11 total), please visit the HSDB record page.

During the Minnesota Children's Pesticide Exposure Study, in which monitoring was performed on children aged 3 to 12, 3,4,6-trichloro-2-pyridinol, a metabolite of chlorpyrifos, was detected in urine samples collected on day 3 (detected in 93% of 87 samples), 5 (detected in 87% of 87 samples), and 7 (detected in 97% of 89 samples) at median concentrations of 7.2, 6.7, and 8.3 ug/L, respectively(1). A urinary metabolite (3,5,6-trichloro-2-pyridinol) of chlorpyrifos was detected in the urine of 5.8% of 6990 samples collected from the general population (persons 12-74 years old) during 1976-1980(2). The mean concentration of urinary chlorpyrifos metabolites found in the urine of pest control operators in Texas was 5.6-8.3 ug/8 hours(3). Chlorpyrifos metabolites were detected in 50 of 60 samples of urine of children 1-6 years of age living in farm-worker households in eastern North Carolina in 2004(4). Chlorpyrifos was one of several pesticides that were most frequently detected in umbilical cord serum samples from a study of 150 women in New Jersey that underwent elective cesarean delivery(5). Chlorpyrifos biomarkers have been detected in the urine of pet owners (both adults and children) who have been exposed to chlorpyrifos through the use of shampoos, dips and impregnated collars containing chlorpyrifos(6).

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.

Chlorpyrifos (CPF) is one of the most widely used organophosphorous insecticides in agriculture with its attendant adverse health outcomes. This study aimed at evaluating the effect of subchronic oral CPF administration on hematological and serum biochemical indices, and the possible ameliorating effect of vitamin C on the indices in mice. Thirty mice divided into 3 groups of 10 mice each were used for this study. Mice in group I (control) were dosed with vegetable oil, while those in group II were given CPF (21.3 mg/kg~ 1/5(th) LD50) only. Mice in group III were pretreated with vitamin C (100 mg/kg) prior to dosing with CPF 30 min later (Vitamin C + CPF-treated group). This regime was given to each group of mice three times a week for a period of ten weeks. During the study period, mice were examined for signs of toxicity, and weight of each mouse was measured every week. At the end of the study period, blood samples were collected from the mice and analyzed for packed cell volume (PCV), total red blood cell (RBC), white blood cell (WBC) and total protein (TP). Serum obtained from the blood was analyzed for Na(+, K+ and Cl-), urea, creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP). The results showed that mice in the vitamin C + CPF-treated group exhibited milder signs of toxicity and significant increase in weight gain (p<0.01) compared to the CPF-treated group. No significant increase in weight in the CPF-treated group was observed compared to the control. There was a significant increase in PCV, RBC, Hb, TP and creatinine, but a significant decrease was obtained in WBC, ALT and AST in the CPF-treated group compared to the control. All the parameters with the exception of WBC, ALT and AST (which increased significantly), were significantly decreased in the vitamin C + CPF-treated group compared to CPF-treated group. ALP was significantly elevated in the CPF-treated group compared to both the control and vitamin C + CPF-treated group. No significant changes in urea and the measured electrolytes in all three groups, except a significant decrease in the concentration of Na(+) was observed in the CPF-treated group compared to the control. The study demonstrated that pretreatment of CPF-administered mice with vitamin C significantly altered some important hematological and serum biochemical parameters, revealing the protective action of the vitamin against some organ damage induced by CPF.

... Interestingly, clinical evidence suggests that exposure to organophosphates might be linked to increased ethanol sensitivity and reduced voluntary consumption of ethanol-containing beverages in humans. ... Present study specifically evaluated neurobiological and behavioral responses to ethanol in Wistar rats that were previously exposed to the pesticide organophosphate chlorpyrifos (CPF). In agreement with clinical data, animals pretreated with a single injection of CPF showed long-lasting ethanol avoidance that was not secondary to altered gustatory processing or enhancement of the aversive properties of ethanol. Furthermore, CPF pretreatment increased ethanol-induced sedation without altering blood ethanol levels. An immunocytochemical assay revealed reduced c-fos expression in the Edinger-Westphal nucleus following CPF treatment, a critical brain area that has been implicated in ethanol intake and sedation. /It was hypothesized/ ... that CPF might modulate cellular mechanisms (decreased intracellular cAMP signaling, alpha-7-nicotinic receptors, and/or cerebral acetylcholinesterase inhibition) in neuronal pathways critically involved in neurobiological responses to ethanol.

... The effects of developmental exposure to terbutaline, a beta2-adrenergic receptor agonist used to arrest preterm labor, and chlorpyrifos, a widely used organophosphate pesticide, on serotonin (5HT) systems /were examined/. Treatments were chosen to parallel periods typical of human developmental exposures, terbutaline (10 mg/kg) on postnatal days (PN) 2-5 and chlorpyrifos (5 mg/kg) on PN11-14, with assessments conducted in juvenile and adolescent stages (PN21, PN30 and PN45), comparing each agent alone as well as sequential administration of both. By itself, terbutaline produced persistent 5HT presynaptic hyperactivity as evidenced by increased 5HT turnover in brain regions containing 5HT terminal zones; this effect was similar to that seen in earlier studies with chlorpyrifos administration during the same early postnatal period. Later administration of chlorpyrifos (PN11-14) produced a transient increase in 5HT turnover during the juvenile stage, and the sequential exposure paradigm, terbutaline followed by chlorpyrifos, showed a corresponding increase in effect over either agent alone. ... the interaction between terbutaline and chlorpyrifos suggests that tocolytic therapy may alter the subsequent susceptibility to common environmental toxicants.

Addition of ascorbic acid to the diet (0.5%) enhanced the acute toxicity of leptophos, chlorpyrifos and diazinon and protected a number of the monitored serum enzymes from being decreased except for leptophos.

For more Interactions (Complete) data for CHLORPYRIFOS (15 total), please visit the HSDB record page.

Neurological (Nervous System)

respiratory system, central nervous system, peripheral nervous system, plasma cholinesterase

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.

LC50; Species: Coturnix (Japanese quail) oral 293 ppm for 5 days (95% confidence limit 112-767 ppm) /Technical material, 97% active ingredient/

LD50; Species: Coturnix coturnix (Japanese quail) 2.5 month old males; oral 15.9 mg/kg (95% confidence limit: 10.5-24.0 mg/kg) /purity 94.5%/

LD50; Species: Coturnix coturnix (Japanese quail) 2-month old males; oral 17.8 mg/kg (95% confidence limit: 15.0-21.2 mg/kg) /purity 94.5%/

LD50; Species: Anas platyrhynchos (Mallard duck) female; oral 75.6 mg/kg (95% confidence limit: 35.4-161 mg/kg) /purity 99%/

For more Ecotoxicity Values (Complete) data for CHLORPYRIFOS (79 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), measured Koc values of 995 to 31,000(2), indicate that chlorpyrifos is expected to have low to no mobility in soil(SRC). Volatilization of chlorpyrifos from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 3.55X10-5 atm-cu m/mole(3). The volatilization half-life of chlorpyrifos from 3 moist soils was in the range of 45-163 hours using an airstream of 1 km/hr passed over the soil(2). An experimental volatilization half-life of 3 days was determined for chlorpyrifos from moist soil surfaces in one laboratory study(4). Chlorpyrifos volatilizes slowly from dry soil surfaces(SRC); 0.64% of applied chlorpyrifos volatilized after 3.2 days in one study(5). In several tests lasting 7-11 days, chlorpyrifos applied to turf lost a mean amount of 8.25% to volatilization(6). Photodegradation of chlorpyrifos on soil surfaces exposed to sunlight has been observed to occur(7). Results of laboratory studies using non-sterile versus sterilized soils(2) have shown that biodegradation is an important fate process(SRC). In one study, half-lives of one week (sandy loam) and 2.5 weeks (organic) in non-sterile soils versus half-lives of 17 and 40 weeks in the sterilized soils were observed respectively(8). A compilation of field dissipation half-lives reports a half-life range of 4-139 days with an approximate median of 43 days(9). Field dissipation half-lives can typically range from 33-56 days for soil incorporated applications and 7-15 days for surface applications(10). The primary route of degradation is transformation to 3,5,6-trichloropyridin-2-ol, which is subsequently degraded to organochlorine compounds and carbon dioxide(10).

TERRESTRIAL FATE: A laboratory experiment was conducted to study the persistence and metabolism of chlorpyrifos in Gangetic Alluvial soil of West Bengal and also to evaluate their effect on the availability of the major plant nutrients (N, P and K) in soil following the application of chlorpyrifos at 1 kg (T1), 10 kg (T2) and 100 kg (T3) a.i./ha. The dissipation followed first order kinetics and the calculated half-life (T1/2) values ranged from 20 to 37 days. The primary metabolite of chlorpyrifos, 3,5,6-trichloropyridinol (TCP) was detected from 3rd day after application and was at maximum on 30th day which decreased progressively to non-detectable level (NDL) on 120th day for all the treatment doses. The secondary metabolite 3,5,6-trichloro-2-methoxy pyridine (TMP) was detected on 30th, 15th and 7th day in T1, T2 and T3 doses respectively which decreased to NDL during 90-120th day. ...

MODERATELY RESIDUAL ON PLANT SURFACES, QUITE RESIDUAL ON INERT SURFACES /SUCH AS WOOD/. VOLATILE ENOUGH TO FORM RESIDUES ON NEARBY SURFACES ...

(14)C- & (36)Cl-labeled dursban was applied to cranberry bean & corn leaves. Within 3 days about 80% of radioactivity was lost presumbably by volatilization.

For more Environmental Fate (Complete) data for CHLORPYRIFOS (6 total), please visit the HSDB record page.

Chlorpyrifos was detected in 2 of 360 food composites collected between Aug 1972 and July 1973 during the FDA's Total Diet Study at a concentration of 0.005 ppm in one fruit composite and 0.003 ppm in one grain-cereal composite(1). It was detected in 4 of 240 food composites collected between Oct 1977 and Sept 1978 during FDA's Total Diet Study at concentrations of 0.006-0.009 ppm in 3 grain-cereal composites and 0.012 ppm in one fruit composite(2). It was detected in 9 of 240 adult food composites collected between Oct 1978 and Sept 1979 during the FDA's Total Diet Study at concentrations of trace to 0.008 ppm(3); it was detected in one of 110 infant and toddler food composites collected between Oct 1978 and Sept 1979 a concentration of 0.004 ppm in one grain-cereal composite(4). It was detected in 2 of 240 food composites collected between Oct 1979 and Sept 1980 during the FDA's Total Diet Study at a concentration of 0.002 ppm in one grain-cereal composite and at a trace level (below 0.0001 ppm) in one garden fruit composite (5). In a summary of monitoring results from three Federal programs (FDA Total Diet Study, FDA Monitoring Program, USDA National Residue Program), chlorpyrifos was reported as infrequently detected in various food products such as fruit, vegetables, grains, and processed foods(6). Chlorpyrifos was identified, not quantified, in 3% of adult foods during an FDA survey from 1978-1982(7) and in 8% of adult foods from 1982-1986(8).

During an FDA survey of domestic foods from 1985-1991 chlorpyrifos was detected in 283 of 2,464 apples at a max concentration of 0.9 ppm, 3 of 2,739 milk samples at trace concentrations, 297 of 862 oranges at a max concentration of 0.76 ppm and 3 of 571 pears at a max concentration of 0.01 ppm(1). In an FDA survey of imported foods from 1985-1991, chlorpyrifos was detected in 87 of 735 apples at a max concentration of 0.11 ppm, 121 of 1,097 bananas at a max concentration of 0.25 ppm, 1 of 64 orange juice samples at trace concentrations, 17 of 474 oranges at a max concentration of 0.28 ppm and 25 of 816 pears at a max concentration of 0.06 ppm(1). In an FDA survey of children foods, chlorpyrifos was detected in cereals (max concentrations 0.001-0.003 ppm), meat dinners (max concentration 0.0008-0.004 ppm), poultry dinners (max concentrations 0.004-0.005 ppm), deserts (max concentrations 0.002-0.003 ppm), fruits and juices (max concentration 0.001-0.006 ppm) and vegetables (max concentration 0.001-0.004 ppm)(1). Chlorpyrifos was detected in citrus fruit from Spain in 1994-1995 at concentrations of 0.1-0.6 mg/kg(2). In an FDA survey of foods in 1993-1994, chlorpyrifos was detected in 132 of 769 domestic apples at a max concentration of 0.21 ppm and in 98 of 1,062 imported apples at a max concentration of 0.05 ppm(3). In a study of 21 commercial juice samples purchased in Madrid, Spain supermarkets chlorpyrifos was detected in 2 of 3 apple juice samples at concentrations of 0.5 and 1.4 ug/kg, 5 of 5 peach juice samples at a concentration range of 0.6 to 3.2 ug/kg, 2 of 6 orange juice samples at concentrations of 1.2 and 2.1 ug/kg, 1 of 5 pineapple juice samples at a concentration of 1.1 ug/kg, and was not detected in a grape juice sample(4). Chlorpyrifos was detected in honey samples collected from 33 cities in Turkey in 2004 at a mean concentration of 132 ng/g(5). Spinach from a retail market in Nanjing China contained chlorpyrifos residues of 0.106-0.204 ug/g fresh wt(6).

Imported wheat samples in Pakistan (22.5% of samples tested) were found to contain chlorpyrifos at levels of 0.073-0.230 ug/g(1).

The substance can be absorbed into the body by inhalation, through the skin and by ingestion.

inhalation, skin absorption, ingestion, skin and/or eye contact

Oral (L268) ; inhalation (L268) ; dermal (L268)

ENVIRONMENTAL: Chlorpyrifos was positively detected in 9 of 298 samples of raw cow's milk (1 ug/kg limit of detection) collected in Italy(1). Samples of human milk collected from 2002-2007 in the San Francisco Bay area (urban) and Salinas, CA area (agricultural) contained median chlorpyrifos concentrations of 24.5 and 28.0 pg/g respectively(2).

EXPERIMENTAL: ... lactating goats were fed [(14)C]ring labeled chlorpyrifos twice daily by capsule; little radiolabel (0.05-0.14%), mainly associated with chlorpyrifos, was recovered in milk.

EXPERIMENTAL: In study of chlorpyrifos residues in cow milk, parent compound & 3,5,6-trichloropyridinol were present in very small amt (about 0.01 ug/g) following dose of 30 ppm daily for 2 wk.

Many of /the organophosphorus insecticides/ are excreted in the milk ... /Organophosphorus insecticides/

Tolerances are established for residues of the pesticide chlorpyrifos per se (O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) in or on the following food commodities:[Table#1167]

A tolerance of 0.1 part per million is established for residues of chlorpyrifos, per se, in or on food commodities (other than those already covered by a higher tolerance as a result of use on growing crops) in food service establishments where food and food products are prepared and served, as a result of the application of chlorpyrifos in microencapsulated form.

Tolerances with regional registration, as defined in 180.1(l), are established for residues of the pesticide chlorpyrifos per se (O,O-diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) in or on the following food commodities:[Table#1168]

EPA has concluded, after completing its assessment of the cumulative risks associated with exposures to all of the OPs /including chlorpyrifos/, 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.

For more FIFRA Requirements (Complete) data for CHLORPYRIFOS (7 total), please visit the HSDB record page.

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 1 lb or 0.454 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).

Chlorpyrifos 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.

The toxicity of chlorpyrifos is probably the result of metabolic conversion to its oxygen analog, chlorpyrifos-oxon, and its subsequent inhibition of various enzymes (eg, cholinesterases, carboxylases, acetylcholinesterases, and mitochondrial oxidative phosphorylases).

The organophosphorus insecticides have been known for many years to cause cholinergic crisis in humans as a result of the inhibition of the critical enzyme acetylcholinesterase. The interactions of the activated, toxic insecticide metabolites (termed oxons) with acetylcholinesterase have been studied extensively for decades. However, more recent studies have suggested that the interactions of certain anticholinesterase organophosphates with acetylcholinesterase are more complex than previously thought since their inhibitory capacity has been noted to change as a function of inhibitor concentration. In the present report, chlorpyrifos oxon (O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphate) was incubated with human recombinant acetylcholinesterase in the presence of p-nitrophenyl acetate in order to better characterize kinetically the interactions of this oxon with enzyme. Determination of the dissociation constant, K(d), and the phophorylation rate constant, k(2), for chlorpyrifos oxon with a range of oxon and p-nitrophenyl acetate concentrations revealed that K(d), but not k(2), changed as a function of oxon concentration. Changes in p-nitrophenyl acetate concentrations did not alter these same kinetic parameters. The inhibitory capacity of chlorpyrifos oxon, as measured by k(i) (k(2)/K(d)), was also affected as a result of the concentration-dependent alterations in binding affinity. These results suggest that the concentration-dependent interactions of chlorpyrifos oxon with acetylcholinesterase resulted from a different mechanism than the concentration-dependent interactions of acetylthiocholine. In the latter case, substrate bound to the peripheral anionic site of acetylcholinesterase has been shown to reduce enzyme activity by blocking the release of the product thiocholine from the active site gorge. With chlorpyrifos oxon, the rate of release of 3,5,6-trichloro-2-pyridinol is irrelevant since the active site is not available to interact with other oxon molecules after phosphorylation of Ser-203 has occurred.

... Mechanisms contributing to the adverse effects of chlorpyrifos (CPF) on DNA synthesis, cell number and size, and cell signaling mediated by adenylyl cyclase (AC) in PC12 cells, a neuronotypic cell line that recapitulates the essential features of developing mammalian neurons /were concluded/ . ... In undifferentiated cells, cholinergic receptor antagonists had little or no protective effect against the antimitotic actions of CPF; however, when nerve growth factor was used to evoke differentiation, the antagonists showed partial protection against deficits in cell loss and alteration in cell size elicited by CPF, but were ineffective in preventing the deterioration of AC signaling. Nicotine, which stimulates nicotinic acetylcholine receptors but also possesses a mixture of prooxidant/antioxidant activity, had adverse effects by itself but also protected undifferentiated cells from the actions of CPF and had mixed additive/protective effects on cell number in differentiating cells. The antioxidant vitamin E also protected both undifferentiated and differentiating cells from many of the adverse effects of CPF but worsened the impact on AC signaling. Theophylline, which prevents the breakdown of cyclic AMP, was the only agent that restored AC signaling to normal or supranormal levels but did so at further cost to cell replication. ... /It was concluded that the/ results show definitive contributions of cholinergic hyperstimulation, oxidative stress, and interference with AC signaling in the developmental neurotoxicity of CPF and point to the potential use of this information to design treatments to ameliorate these adverse effects.

Organophosphorus derivatives act by combining with and inactivating the enzyme acetylcholinesterase (AChE). ... The inactivation of cholinesterase by cholinesterase inhibitor pesticides allows the accumulation of large amounts of acetylcholine, with resultant widespread effects that may be ... separated into 4 categories: (1) Potentiation of postganglionic parasympathetic activity. ... (2) Persistent depolarization of skeletal muscle ... (3) Initial stimulation following depression of cells of central nervous system ... (4) Variable ganglionic stimulation or blockade ... /Cholinesterase inhibitor pesticides/

For more Mechanism of Action (Complete) data for CHLORPYRIFOS (6 total), please visit the HSDB record page.

A dose of 50 mg/kg bw [(36)Cl] chlorpyrifos given orally to male Wistar rats by intubation ...The concentrations of residue were highest in liver and kidney 4 hr after dosing, but the half-life in these tissues was < 20 hr. The longest half-time, 62 hr, was recorded in fat.

In persons poisoned with chlorpyrifos formulations, chlorpyrifos was detected in serum samples only and at lower concentration than the diethylphosphorus metabolites, which were excreted mainly in urine. The urinary diethylphosphorus metabolites were excreted by first-order kinetics, with an average elimination half-life of 6.1 + or - 2.2 hr in the fastest phase and 80 + or - 26 hr in the slowest.

... Five volunteers ingested 1 mg (2852 nmol) of chlorpyrifos. Blood samples were taken over 24 hours and total void volumes of urine were collected over 100 hours. Four weeks later 28.59 mg (81567 nmol) of chlorpyrifos was administered dermally to each volunteer for 8 hours. ... The apparent elimination half-life of urinary dialkylphosphates after the oral dose was 15.5 hours and after the dermal dose it was 30 hours. ...

Urinary ... biological half-life of chlorpyrifos (O, O-diethyl-O-3,5,6-trichloro-2-pyridinyl phosphorothioate) ... /was/ investigated. Male Wistar rats weighing 200 g were intraperitoneally injected with chlorpyrifos at a level of 0.2 mmol/kg body weight. Both chlorpyrifos and 3,5,6-trichloro-2-pyridinol (TCP) levels in blood showed maximum values at 5 hr post-injection, and then decreased rapidly. Biological half-lives of the blood chlorpyrifos and TCP were estimated to 8.15 and 24.66 hr, respectively. ...

For more Biological Half-Life (Complete) data for CHLORPYRIFOS (6 total), please visit the HSDB record page.

Metabolism of Dursban in fish was studied in a tank ... After exposure to Dursban, the fish were sacrificed and the fish and some water examined by paper chromatography. In addition to oxygen analog (ii) of Dursban, the monoethyl analog (iii) of Dursban and its oxygen analog (iv), 3,5,6-trichloro-2-pyridyl phosphate (v), and 3,5,6-trichloro-2-pyridinol (vi) were also found. In the fish tissues themselves, compounds ii, iv, v, vi were found.

Two goats were fed [(14)C]ring labeled (positions 2 and 6) chlorpyrifos twice daily in capsules for 10 days at concentrations equivalent to 15-19 ppm in the feed. The majority (80%) of the radiolabel was recovered in urine, with smaller amounts in feces (3.6%), gut (0.9%), tissues (0.8%), and milk (0.1%). The major urinary metabolite (> 75% of the residual radiolabel) was the beta-glucuronide conjugate of TCP, with smaller amounts of unconjugated TCP. The major residue in fat was chlorpyrifos (0.12 ppm), while TCP was the major residue in liver and kidney. A similar pattern of elimination was seen in a study in which lactating goats were fed [(14)C]ring labeled chlorpyrifos twice daily by capsule; little radiolabel (0.05-0.14%), mainly associated with chlorpyrifos, was recovered in milk.

Chlorpyrifos (CPF) is a commonly used diethylphosphorothionate organophosphorus (OP) insecticide. Diethylphosphate (DEP), diethylthiophosphate (DETP) and 3,5,6-trichloro-2-pyridinol (TCPy) are products of metabolism and of environmental degradation of CPF and are routinely measured in urine as biomarkers of exposure. However, because these same chemicals can result from metabolism or by biodegradation, monitoring total urinary metabolite levels may be reflective of not only an individual's contact with the parent pesticide, but also exposure with the metabolites, which are present in the environment. The objective of the current study was to compare the pharmacokinetics of orally administered DEP, DETP and TCPy with their kinetics following oral dosing with the parent insecticide CPF in the rat. Groups of rats were orally administered CPF, DEP, TCPy or DETP at doses of 140 umol/kg body weight, and the time-courses of the metabolites were evaluated in blood and urine. Following oral administration, all three metabolites were well absorbed with peak blood concentrations being attained between 1 and 3 hr post-dosing. In the case of DEP and TCPy virtually all the administered dose was recovered in the urine by 72 hr post-dosing, suggesting negligible, if any, metabolism; whereas with DETP, approximately 50% of the orally administered dose was recovered in the urine. The CPF oral dose was likewise rapidly absorbed and metabolized to DEP, TCPy and DETP, with the distribution of metabolites in the urine followed the order: TCPy (22+/-3 umol)>DETP (14+/-2 umol)>DEP (1.4+/-0.7 umol). Based upon the total amount of TCPy detected in the urine a minimum of 63% of the oral CPF dose was absorbed. These studies support the hypotheses that DEP, DETP and TCPy present in the environment can be readily absorbed and eliminated in the urine of rats and potentially humans.

Non-invasive biomonitoring approaches are being developed using reliable portable analytical systems to quantify dosimetry utilizing readily obtainable body fluids, such as saliva. In the current study, rats were given single oral gavage doses (1, 10, or 50 mg/kg) of the insecticide chlorpyrifos (CPF). Saliva and blood were then collected from groups of animals (4/time-point) at 3, 6, and 12 hr post-dosing, and were analyzed for the CPF metabolite trichloropyridinol (TCP). Trichloropyridinol was detected in both blood and saliva at all doses and the TCP concentration in blood exceeded saliva, although the kinetics in blood and saliva were comparable. A physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model for CPF incorporated a compartment model to describe the time-course of TCP in blood and saliva. The model adequately simulated the experimental results over the dose ranges evaluated. A rapid and sensitive sequential injection (SI) electrochemical immunoassay was developed to monitor TCP, and the reported detection limit for TCP was 6 ng/L (in water). ...

For more Metabolism/Metabolites (Complete) data for CHLORPYRIFOS (23 total), please visit the HSDB record page.

Chlorpyrifos has known human metabolites that include Diethyl phosphorothioate, 3,5,6-Trichloro-2-pyridinol, and Chlorpyrifos-oxon.

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.

... Five volunteers ingested 1 mg (2852 nmol) of chlorpyrifos. Blood samples were taken over 24 hours and total void volumes of urine were collected over 100 hours. Four weeks later 28.59 mg (81567 nmol) of chlorpyrifos was administered dermally to each volunteer for 8 hours. Unabsorbed chlorpyrifos was washed from the skin and retained for subsequent measurement. The same blood and urine sampling regime was followed as for the oral administration. Plasma and erythrocyte cholinesterase concentrations were determined for each blood sample. The concentration of two urinary metabolites of chlorpyrifos, diethylphosphate and diethyl-thiophosphate was determined for each urine sample. ... Most of the oral dose (mean (range) 93% (55-115%)) and 1% of the applied dermal dose was recovered as urinary metabolites. About half (53%) of the dermal dose was recovered from the skin surface. The absorption rate through the skin, as measured by urinary metabolites was 456 ng/sq cm/hr. ...

Male volunteers received chlorpyrifos as an oral dose of 0.5 mg/kg bw and 1 month later a dermal dose of 5 mg/kg bw. The time to the maximal concentration of TCP in blood was 0.5 hr after oral dosing and 22 hr after dermal treatment. The elimination half-time, irrespective of the route of administration, was 27 hr. The percentage of the administered dose recovered from the urine was 70% after oral dosing and 1.3% after dermal administration.

In persons poisoned with chlorpyrifos formulations, chlorpyrifos was detected in serum samples only and at lower concentration than the diethylphosphorus metabolites, which were excreted mainly in urine.

By 72 hr after a single oral dose of 19 mg/kg bw [(14)C]ring-labelled chlorpyrifos was given by intubation to male Sprague-Dawley rats, 83-87% had been eliminated, mainly in the urine (68-70%), feces (14-15%), and expired air (0.15-0.39%). The residues found at this time represented about 1.7% of the total dose, and the concentration, while highest in fat, was < 1 ppm in any tissue.

For more Absorption, Distribution and Excretion (Complete) data for CHLORPYRIFOS (21 total), please visit the HSDB record page.

Widely used in homes and on farms for cockroaches, fleas, termites, ticks, and crop pests; [ATSDR ToxFAQs]

Farming (Pesticides) [Category: Industry]

For chlorpyrifos (USEPA/OPP Pesticide Code: 059101) 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./

Chlorpyrifos is an organophosphate insecticide, acaricide, and miticide used to control foliage and soil-borne insect pests on a variety of food and feed crops.

... Broad-spectrum organophosphate insecticide with wide spread use on food commodities, turf, and ornamental plants. ... commonly used indoors to control structural pests. It is one of the most widely used pesticides in the United States and has been one of the top five insecticides used in residential settings ...

Insecticide; Used for control of Coleoptera, Diptera, Homoptera and Lepidoptera in soil or on foliage in over 100 crops, including pome fruit, stone fruit, citrus fruit, nut crops, strawberries, figs, bananas, vines, vegetables, potatoes, beet, tobacco, soya beans, sunflowers, sweet potatoes, peanuts, rice, cotton, alfalfa, cereals, maize, sorghum, asparagus, glasshouse and outdoor ornamentals, turf, and in forestry. Also used for control of household pests, mosquitoes (larvae and adults) and in animal houses.

/SRP/: diethyl sulfide & diethyl disulfide are volatile contaminants which are partly responsible for the offensive odor of the technical grade.

Impurities /found in the technical product (94.0% active ingredient)/ ... included: some residual solvent, methylene chloride; unreacted O,O-diethyl-phosphorochloridothioate, 3,5,6-trichloro-2-pyridinol; the S-ethyl isomer of chlorpyrifos, and other isomeric and related chloropyridyl phosphorothioates and phosphates; compounds related to 3,5,6-trichloro-2-pyridinol; and trace amounts of sulfotep.

O-Ethyl O,O-bis(3,5,6-trichloro-2-pyridyl) phosphorothioate does not occur as a significant impurity in /technical product (94.0% of active ingredient)/.

Approximately 10 million pounds are applied annually in agricultural settings. The largest agricultural market for chlorpyrifos in terms of total pounds ai is corn (ca 5.5 million).

Chlorpyrifos use as a termiticide is significant, with a recent estimate of seven million pounds ai applied annually, constituting about 30% of the total annual use.

INSECTICIDE USED ON CORN, 39%; ALFALFA, 6%; COTTON, 3%; SORGHUM, 1%; OTHER FIELD CROPS-EG, CITRUS & DECIDUOUS FRUITS/NUTS, 21%; NON-AGRICULTURAL USES, 31% (1982)

(1978) 4.00X10+9 G (CONSUMPTION)

(1982) 3.27X10+9 G (CONSUMPTION)

Chlorpyrifos can be prepared by reaction of 3,5,6-trichloro-2-pyridinol with diethyl phosphorochloridothioate in the presence of sodium carbonate.

Preparation: R. H. Rigterink, France 1360901; idem United States of America 3244586 (1964, 1966, both to Dow)

The National Pesticide Information Retrieval System (NPIRS) identifies 32 companies with active labels for products containing the chemical chlorpyrifos. To view the complete list of companies, product names and percent chlorpyrifos in formulated products click the following url and enter the CAS Registry number in the Active Ingredient field.

Chlorpyrifos SPC 2.32% G Insecticide (Nufarm Americas, Inc.): Active ingredient: chlorpyrifos 2.32%.

Nufarm Chlorpyrifos SPC 1.0% MCB Insecticide (Nufarm Americas, Inc.): Active ingredient: chlorpyrifos 1.0%.

Nufarm Chlorpyrifos SPC 4 Insecticide (Nufarm Americas, Inc.): Active ingredient: chlorpyrifos 44.7%.

For more Formulations/Preparations (Complete) data for CHLORPYRIFOS (43 total), please visit the HSDB record page.

Chemical Classes -> Organophosphates and carbamates

Environmental transformation -> Pesticides (parent, predecessor)

Insecticides

INSECTICIDES

The WHO Recommended Classification of Pesticides by Hazard identifies chlorpyrifos (technical grade) as Class II: moderately hazardous; Main Use: insecticide.

Types and methods of application: Ground and aerial, spray and dust applications.

Application rates: Range from 0.5 lb active ingredient (ai)/acre to 3 lb active ingredient (ai)/acre, and crack and crevice treatment to broadcast treatment for indoor uses.

/Dursban is a/ trademark for insecticides containing O,O-diethyl-O-3,5,6-trichloro-2-pyridyl phosphorothioate.

For more General Manufacturing Information (Complete) data for CHLORPYRIFOS (7 total), please visit the HSDB record page.