Agent Name |
Methyl isocyanate |
CAS Number |
624-83-9 |
Formula |
C2-H3-N-O |
Major Category |
Toxic Gases & Vapors |
Synonyms |
Iso-cyanatomethane; Isocyanate de methyle [French]; Isocyanate, methyl-; Isocyanic acid, methyl ester; Methane, isocyanato-; Methyl carbonimide; Methyl isocyanat [German]; Methyl isocyanat [German]; Methyl isocyanate; Methyl isocyanide; Methylcarbylamine; Methylisocyanaat [Dutch]; Methylisokyanat [Czech]; Metil isocianato [Italian]; TL 1450; [ChemIDplus] UN2480 |
Category |
Monoisocyanates |
Description |
Colorless liquid with a sharp, pungent odor; [NIOSH] |
Sources/Uses |
Used in the production of insecticides, herbicides, polyurethanes, and other plastics; [ACGIH] |
Comments |
Methyl isocyanate can cause eye and skin injuries, pulmonary edema, and possibly immunological asthma. Skin sensitivity to methyl isocyanate developed in all sixteen guinea pigs tested. [ACGIH] Causes second and third degree burns after short skin exposures; [CHRIS] In high-dose reproductive studies of animals, methyl isocyanate decreases fertility and increases fetal losses and birth defects. Women exposed in the Bhopal disaster had higher rates of spontaneous abortions than controls. [Frazier, p. 344-5] A lachrymator; [HSDB] Methyl isocyanate is fibrogenic to the lungs in the context of an acute inhalation exposure complicated by bronchiolitis obliterans. |
Reference Link |
ATSDR Medical Management - Methyl Isocyanate |
Exposure Assessment |
Skin Designation (ACGIH) |
Yes |
TIH |
Yes |
TLV (ACGIH) |
0.02 ppm |
PEL (OSHA) |
0.02 ppm |
MAK |
0.01 ppm |
IDLH (NIOSH) |
3 ppm |
Excerpts from Documentation for IDLHs |
Lacrimation and irritation of the eyes, mucous membranes and skin; "Human data: Volunteers experienced eye irritation and lacrimation after 1 to 5 minutes at 2 ppm, with more marked irritation at 4 ppm; exposures were unbearable at 21 ppm [Kimmerle and Eben 1964]. In another study, volunteers noted eye irritation and lacrimation at 5 ppm in less than 50 seconds [Mellon 1963]. |
Vapor Pressure |
348 mm Hg |
Odor Threshold Low |
2.1 ppm |
Lethal Concentration |
LC50 (rats) = 6.1 ppm/6 hr |
Explanatory Notes |
Odor threshold from AIHA; Flash point = -7 deg C; |
Reference Link |
International Chemical Safety Cards (WHO/IPCS/ILO) |
Flammability (NFPA) |
3: may ignite at ambient temperature |
Adverse Effects |
Asthma |
Yes |
Toxic Pneumonitis |
Yes |
Fibrogenic |
Yes |
Dermatotoxin |
Skin Burns |
Skin Sensitizer |
Yes |
Lacrimator |
Yes |
Reproductive Toxin |
Yes |
Links to Other NLM Databases |
Health Studies |
Human Health Effects from Hazardous Substances Data Bank: METHYL ISOCYANATE
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