Chlorpyrifos-methyl

Synonyms

Chlorpyrifos O,O-dimethyl analog; Chloropyriphos-methyl; Chlorpyrifos methyl; Chlorpyriphos-methyl [ISO-French]; Dowco 214; Dursban methyl; ENT 27520; M 3196; Methyl chlorpyrifos; Methyl chlorpyriphos; Methyl dursban; Methylchlorpyrifos; Noltran; O,O-Dimethyl O-(3,5,6-trichloro-2-pyridinyl) phosphorothioate (8CI)(9CI); O,O-Dimethyl O-(3,5,6-trichloro-2-pyridyl)phosphorothioate; O,O-Dimethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate; OMS-1155; Reldan; Reldan 50 EC; Trichlormethylfos; Tumar; Zertell; [ChemIDplus]

Category

Organophosphate Insecticides

Description

White or amber solid; [HSDB] Colorless solid; [CAMEO]

Sources/Uses

Used as insecticide, acaricide, and veterinary ectoparasiticide; [Merck Index] Used mainly to protect cereals (including storage); [HSDB] Used as insecticide for stored grains, rice, oil crops, and animal feed; [Reference #1]

Comments

A skin irritant; [SAX] May cause skin sensitization; [eChemPortal: ESIS] In a two year feeding study with rats (highest dose level 1 mg/kg/day) no significant adverse gross or histopathological changes were observed as well as no relation to frequency of spontaneous tumors; Effects in a three generation feeding study with rats include inhibition of cholinesterase activity and decreased pup weights in the second and third generation; No significant effects were observed in fertility, gestation, viability, or lactation; No gross or histopathological changes were noted in third generation parental animals; No teratogenic effects observed in a study with rats; [Reference #2] “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] See "Chlorpyrifos."

Reference Link #1

Biomedical References

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]

4.22E-05 mm Hg

LC50 (rat) > 670 mg/m3/4h

Reference Link #2

Other Poison

Organophosphate

Diseases

Occupational diseases associated with exposure to this agent:

• Organophosphates & carbamates, acute poisoning

Processes

Industrial Processes with risk of exposure:

• Farming (Pesticides)