Leptophos

Synonyms

(+-)-Leptophos; Abar; Abar (velsicol); Fosvel; K62-105; MBCP; NK 711; O-(2,5-Dichloro-4-bromophenyl) O-methyl phenylthiophosphonate; O-(4-Bromo-2,5-dichlorophenyl) O-methyl phenylphosphonothioate; O-Methyl O-2,5-dichloro-4-bromophenyl phenylthiophosphonate; O-Methyl-O-(4-bromo-2,5-dichlorophenyl)phenyl thiophosphonate; OMS 1438; Oleophosvel; Phenylphosphonothioic acid O-(4-bromo-2,5-dichlorophenyl) O-methyl ester; Phosphonothioic acid, phenyl-, O-(4-bromo-2,5-dichlorophenyl) O-methyl ester (8CI)(9CI); Phosvel; VCS 5-D; VCS-506; Velsicol 506; Velsicol VCS 506; [ChemIDplus]

Category

Organophosphate Insecticides

Description

Tan solid; [Merck Index] Colorless or white solid; Technical material is light-brown solid; [CAMEO]

Sources/Uses

Used as an insecticide; [Merck Index] For export use only; Used as an insecticide for rice, cotton, fruit, and vegetables; [EPA OHM/TADS]

Comments

A small number of the organophosphates (OPs) can Induce Delayed Neuropathy (OPIDN). OPIDN usually occurs after ingestion and is usually nonoccupational. [Levy, p. 431] A highly toxic cholinesterase inhibitor that may cause permanent injury or death as a result of normal use; [CAMEO] A weak cholinesterase inhibitor, but is metabolized to the oxygen analog that is relatively potent; Not teratogenic in rabbits dosed orally during pregnancy; May cause delayed neurotoxicity in occupational exposures (delayed neurotoxicity observed in hens); [EPA OHM/TADS] May cause irritation and organ damage; Highly toxic by ingestion; Toxic by skin absorption; [Aldrich MSDS] “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]

Banned in the USA in 1975 due to delayed neurotoxic effects; [HSDB]

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]

2.3E-08 mm Hg

Predominantly motor

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)