Agent Name

Methyl iodide

Alternative Name

Iodomethane

CAS Number

74-88-4

Formula

C-H3-I

Major Category

Toxic Gases & Vapors

Synonyms

Iodomethane; Monoiodomethane; [NIOSH]

Category

Other Toxic Gases & Vapors

Description

Colorless liquid with a pungent, ether-like odor. [Note: Turns yellow, red, or brown on exposure to light & moisture.] [NIOSH]

Sources/Uses

Used as a methylating agent; used in microscopy because of its high refractive index; [ACGIH]

Comments

Liquid causes second degree burns after contact for a few minutes. [CHRIS] Corrosive to skin; [Quick CPC] In animal feeding studies, methyl iodide is hepatotoxic, "ten times as acutely toxic as carbon tetrachloride." After an industrial accident, an exposed chemical plant worker developed symptoms of central nervous system poisoning and died. [ACGIH] Inhalation can cause pulmonary edema, CNS depression, and death; [CAMEO] A lachrymator; [CHEMINFO] It is an acute pulmonary irritant that can cause chronic neurological symptoms after a heavy dermal exposure. [Reference #1]

Reference Link

Acute methyl iodide exposure with delayed neuropsy...[Am J Ind Med. 2005] - PubMed Result

Exposure Assessment
Skin Designation (ACGIH)

Yes

TIH

Yes

TLV (ACGIH)

2 ppm

PEL (OSHA)

5 ppm

IDLH (NIOSH)

100 ppm

Excerpts from Documentation for IDLHs

Basis for original (SCP) IDLH: The chosen IDLH is based on the mouse 57minute LC50 of 860 ppm [Buckell 1950 cited by Patty 1963]. . . . Other animal data: In a subchronic study, no rats died following exposures to 150 ppm for 6 hours/day for 3 days [Monsanto 1986]. Human data: None relevant for use in determining the revised IDLH.

Vapor Pressure

400 mm Hg

Lethal Concentration

LC50 (rat) = 1,300 mg/m3/4H

Reference Link

EPA Pesticide Chemical Search

Adverse Effects
Lacrimator

Yes

Toxic Pneumonitis

Yes

Neurotoxin

Other CNS Neurotoxin

Hepatotoxin

Hepatotoxin, Secondary

Dermatotoxin

Skin Burns

IARC Carcinogen

Not Classifiable

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information

Search TOXNET

Chemical Information

Search ChemIDplus

Biomedical References

Search PubMed

Related Information in HazMap
Diseases

Occupational diseases associated with exposure to this agent: