Methyl Bromide is used for three main purposes:
When used as a soil fumigant, methyl bromide gas is usually injected into the soil at a depth of 12 to 24 inches before a crop is planted. This will effectively sterilize the soil, killing the vast majority of soil organisms. Immediately after the methyl bromide is injected, the soil is covered with plastic tarps, which slow the movement of methyl bromide from the soil to the atmosphere. Additional methyl bromide is emitted to the atmosphere at the end of the fumigation when the tarps are removed. When an entire field is fumigated, the tarps are removed 24 to 72 hours later, as can be the case in strawberry production in California. However, with row (or bed) fumigation, as is the case with tomato production in Florida, the traps are left on for the entire growing season, some 60 to 120 days. About 50 to 95% of the methyl bromide injected in to the soil can eventually enter the atmosphere. In the United States, strawberries (18% of U.S. total) and tomatoes (23% of U.S. total) are the crops which use the most methyl bromide, consuming about 7,000 tons (14,000,000 pounds) annually. Other crops which use this pesticide as a soil fumigant include tobacco, peppers, grapes, and nut and vine crops.2. Methyl Bromide is used in commodities.
When used as a commodity treatment, methyl bromide gas is injected into a chamber or under a tarp containing the commodities. About 80 to 95% of the methyl bromide used for a typical commodity treatment eventually enters the atmosphere. Commodities which use this material as part of a post-harvest pest control regime include grapes, raisins, cherries, nuts, and imported materials. Some commodities are treated multiple times during both storage and shipment. Commodities may be treated with methyl bromide as part of a quarantine or phytosanitary (QPS) requirement of an importing country.3. Methyl Bromide is used in structures and transport.
Methyl Bromide is used to safeguard buildings, such as grain storage facilities, flour mills, food processing units, or vehicles, such as ships, freight containers, trucks or trains carrying agricultural commodities from all kinds of pests. Also here the degree of containment of Methyl Bromide can vary widely. E.g. Some aircraft and modern buildings can be very gastight whereas older structures can at best be only partially sealed.