Sweet, ethereal odor (no threshold data available); inadequate warning properties

Moderately toxic, volatile substance readily absorbed through skin.

The acute toxicity of methyl iodide is moderate by ingestion, inhalation, and skin contact. This substance is readily absorbed through the skin and may cause systemic toxicity as a result. Methyl iodide is moderately irritating upon contact with the skin and eyes. Methyl iodide is an acute neurotoxin. Symptoms of exposure (which may be delayed for several hours) can include nausea, vomiting, diarrhea, drowsiness, slurred speech, visual disturbances, and tremor. Massive overexposure may cause pulmonary edema, convulsions, coma, and death.

Chronic exposure to methyl iodide vapor may cause neurotoxic effects such as dizziness, drowsiness, and blurred vision. There is limited evidence for the carcinogenicity of methyl iodide to experimental animals; it is not classified as an OSHA "select carcinogen."

Noncombustible. High vapor pressure may cause containers to burst at elevated temperatures.

Methyl iodide may react vigorously with alkali metals and strong oxidizing agents.