Colorless liquid with a sweet, pungent odor. Turns yellow, red or brown when exposed to light or moisture, lachrymator.
Methylating agent, in microscopy because of its high refractive index, as imbedding material for examining diatoms, in testing for pyridine. Light sensitive etching agent for electronic circuits, component in fire extinguishers.
Registry Numbers and Inventories.
EC Index Number
Carcinogenic Category 3; Harmful; Toxic; Irritant
R 21 23/25 37/38 40
S 36/37 38 45
Tumorigen; Mutagen; Primary Irritant
Swiss Giftliste 1
Japan ENCS (MITI)
Melting point, °C
Boiling point, °C
Vapor pressure, mmHg
405 (20 C)
Vapor density (air=1)
526000 ppm at 25 C (calc.)
No information reported, but expected to evaporate readily.
Odor Threshold Odor threshold Odorless
2.279 g/cm3 (20 C)
Solubility in water
0.606 cp at 0C
25.8 g/s2 at 43.5 C in contact with air
1.5293 (20 C)
Partition coefficient, pKow
Heat of vaporization
Heat of combustion
Hazards and Protection.
Do not store in direct sunlight. Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances.
Wash thoroughly after handling. Do not breathe dust, vapor, mist, or gas. Do not get in eyes, on skin, or on clothing. Do not ingest or inhale. Store protected from light. Use only in a chemical fume hood.
Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Absorb spill with inert material, (e.g., dry sand or earth), then place into a chemical waste container. Avoid runoff into storm sewers and ditches which lead to waterways. Provide ventilation. Do not get water inside containers.
Stable under normal temperatures and pressures.
Oxygen, silver chlorite, sodium, and trialkylphosphines
Carbon monoxide, irritating and toxic fumes and gases, carbon dioxide, hydrogen iodide, iodine.
Upper exp. limit, %
Lower exp. limit, %
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Substance is noncombustible. Decomposes at high temperatures, resulting in toxic and corrosive products. Containers may explode in the heat of a fire. Vapors may be heavier than air. They can spread along the ground and collect in low or confined areas. Extinguishing media: Use extinguishing media most appropriate for the surrounding fire. Do NOT get water inside containers. For small fires, use dry chemical, carbon dioxide, or water spray. For large fires, use water spray, fog or regular foam. Cool containers with flooding quantities of water until well after fire is out.
Iodomethane is not flammable.
Toxic and irritating gases are generated when exposed to fire or heat.
NIOSH REL: Ca TWA 2 ppm (10 mg/m3) [skin] See Appendix A OSHA PEL: TWA 5 ppm (28 mg/m3) [skin] IDLH Ca [100 ppm]
Chronic inhalation may cause effects similar to those of acute inhalation.
Harmful if swallowed. May cause irritation of the digestive tract. May cause effects similar to those for inhalation exposure. Prolonged or repeated exposure may cause CNS effects.
Causes respiratory tract irritation. May cause lung damage. May cause spleen and liver damage. Initial symptoms include lethargy, drowsiness, slurred speech, ataxia, muscular incoordination, visual disturbances. May progress to convulsions, coma and death. Other symptoms include giddiness, diarrhea, sleepiness, irritability, vomiting, pallor, muscular twitching and kidney effects.
Causes skin irritation. May cause irritation with pain and stinging, especially if the skin is abraded. May cause reddening of the skin.
Causes eye irritation. Causes redness and pain. If splashed in the eye causes conjunctivitis.
Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately.
Get medical aid immediately. Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. DO NOT use mouth-to-mouth respiration.
Get medical aid. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse.
Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately.
USCG CHRIS Code
2903 30 80
Std. Transport #