Methyl isocyanate

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] Released from a pesticide factory in Bhopal India in 1984, killing about 2.500 people and leaving many survivors with chronic lung disease; [Rom, p. 503-4]

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 #1

Biomedical References

Yes

Yes

0.02 ppm

0.06 ppm

0.02 ppm

0.01 ppm

0.12 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].

348 mm Hg

2.1 ppm

LC50 (rat) = 6.1 ppm/6 hr

Explanatory Notes

Odor threshold from AIHA; Flash point = -7 deg C; VP from HSDB;

Reference Link #2

may ignite at ambient temp

0.025 ppm

0.25 ppm

1.5 ppm

Yes

Yes

Yes

Yes

Yes

Yes

Skin burns

Diseases

Occupational diseases associated with exposure to this agent:

• Asthma, occupational
• Bronchiolitis obliterans
• Contact dermatitis, allergic
• Pneumonitis, toxic