| 有害性の概要 | Bromomethane is a manufactured chemical. It also occurs naturally in small amounts in the ocean where it is formed, probably by algae and kelp. It is a colorless, nonflammable gas with no distinct smell. Other names for bromomethane are methyl bromide, mono-bromomethane, and methyl fume. Trade names include Embafume and Terabol. Bromomethane is used to kill a variety of pests including rats, insects, and fungi. It is also used to make other chemicals or as a solvent to get oil out of nuts, seeds, and wool.Methyl bromide is used as a fumigant and pesticide. Exposure may occur during fumigation activities. Methyl bromide is highly toxic. Studies in humans indicate that the lung may be severely injured by the acute (short-term) inhalation of methyl bromide. Acute and chronic (long-term) inhalation of methyl bromide can lead to neurological effects in humans. Neurological effects have also been reported in animals. Degenerative and proliferative lesions in the nasal cavity developed in rats chronically exposed to methyl bromide by inhalation. Chronic inhalation exposure of male animals has resulted in effects on the testes at high concentrations. EPA has classified methyl bromide as a Group D, not classifiable as to human carcinogenicity.Liquid causes second degree burns after contact for a few minutes[CHRIS] Corrosive to skin[Quick CPC] Methyl bromide is a neurotoxic gas that can cause convulsions, coma, and long-term neuromuscular and cognitive deficits. Exposure to high concentrations of pure methyl bromide may cause inflammation of the bronchi or lungs, an accumulation of fluid in the lung, and irritation of the eyes and nose. [ATSDR Medical Management] Methyl bromide causes liver injury in acute inhalation studies of laboratory animals. [ACGIH] Acts as an alkylating agent of glutathione and other cellular moleculesPoor warning properties, so 2% chloropicrin often added[Olson, p. 321-2] Effects on the CNS, kidneys, and lungs (possible lung edema after inhalation)[ICSC]The major hazards encountered in the use and handling of methyl bromide stem from its toxicologic properties. Toxic by all routes (ie, inhalation, ingestion, and dermal absorption), exposure to this colorless, nearly odorless gas may occur from its use as a fumigant for soil, grain and other commodities, as a solvent, methylating agent, and extracting agent. Effects from exposure may include contact burns to the skin and eyes, dizziness, headache, nausea, respiratory irritation, ventricular fibrillation, pulmonary edema (sometimes delayed 4 to 5 days), convulsions, coma, and death. The OSHA PEL is set at a ceiling limit of 20 ppm, with a notation that skin contact is to be prevented. The ACGIH has recommended a TWA of 5 ppm. Levels should be controlled by local exhaust ventilation, with a continuous monitoring system to warn of excursions. In activities or situations where over-exposure may occur, wear a self-contained breathing apparatus with a full facepiece, and full chemical protective clothing (including gloves and boots) which is specifically recommended by the shipper or producer to prevent skin contact with methyl bromide. If contact should result, immediately flush affected skin or eyes with running water for at least 15 minutes. Remove contaminated clothing and shoes at the site. While methyl bromide does not ignite easily, it may burn with the production of irritating and poisonous gases. Also, containers may explode violently in the heat of a fire. Fires involving methyl bromide may be extinguished with dry chemical, CO2, Halon, or standard foam. Water spray, if used, should be applied with caution because it may cause frothing. Dike runoff from fire-control water. Methyl bromide should be stored in dry, well-ventilated areas, away from sources of ignition, direct sunlight, and sources of physical damage. Choice of containers should take into account methyl bromide's reactivity with aluminum, magnesium, tin, zinc, and other alloys. Certain methods of shipment are forbidden for methyl bromide. Consult with the regulatory requirements of the US Department of Transportation for detailed shipping and labelling instructions. If methyl bromide should spill or leak from a small container or pressurized cylinder, first remove ignition sources, then ventilate the spill area and stop the leak. Isolate the area 75 feet in all directions from the spill. For a large spill, water spray or mist may be necessary to knock down vapor. Dike any surface flow with soil or sandbags to keep the material out of water sources or sewers. Absorb bulk liquid with fly ash or cement powder. Before implementing land disposal of waste methyl bromide, consult with environmental regulatory agencies for guidance. |
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