Fumigation: Insecticides

The following substances and processes are approved as insecticides for use with formaldehyde or any accepted germicide. (a) Ethylene oxide and carbon dioxide: "Carboxide." A mixture of one part ethylene oxide at ordinary temperatures is a colorless gas with a faint odor of ether. At 50°F. it is a mobile colorless liquid. Concentrated vapors of ethylene oxide are inflammable or explosive. To overcome the fire and explosion hazard, carbon dioxide is added. This eliminates these hazards and about doubles the toxicity of the ethylene oxide gas to insects. Ethylene oxide gas penetrates deeply into articles and materials of bedding and upholstery and destroys insects and insect eggs effectively. It is not very toxic to man. "Carboxide" gas is nonexplosive and noninflammable and does not injure fabrics or furniture. The materials to be treated shall be placed in a gas tight chamber on open lattice racks so as to allow the free access of the gas to the materials. The gas should be released into the chamber in the form of a mist or spray. Three pounds of ethylene oxide-carbon dioxide (or "carboxide") per one thousand cubic feet in a gas tight chamber at a temperature of 75°F. will destroy insects and insect eggs in twelve hours; five pounds per one thousand cubic feet is effective in eight hours. (b) Hydrocyanic acid gas. This gas is very dangerous as it is deadly poisonous to man and should be used only by expert operators, licensed by the local health authorities. (See Reg. 21a-235-29.) (c) Methyl formate and carbon dioxides: "Malium." This is a noninflammable liquid consisting of fifteen parts methyl formate and eighty-five parts carbon dioxide by weight. Have air tight room, except for vent pipe to go above roof. Release gas by connecting cylinder to a manifold outside the room with a discharge pipe to the inside room. Moisture in the room is undesirable. Keep the temperature in room at not less than 75°F. Means shall be provided for exhausting vapors after fumigation. Outlet should be above roof. Clear the room of gas before opening the door after fumigation. (d) Ethylene dichloride and carbon tetrachloride. This is a noninflammable liquid mixture of seventy-five per cent of the former and twenty-five per cent of the latter by volume. Ethylene dichloride is inflammable, but the mixture with carbon tetrachloride is not. Use a gas tight room. Place liquid in a shallow trough not more than two and one-half inches deep. Hang it about eighteen inches below the ceiling. The gas is heavy and travels downward. Use not less than fourteen pounds (five quarts) per one thousand cubic feet of air space in the room. Keep the temperature of room at not less than 75°F. nor more than 90°F. Moisture in the room is undesirable. Means shall be provided for exhausting vapors after fumigation. Outlet should be above the roof. Clear the room of gas before opening the door after fumigation. (e) Carbon tetrachloride. Carbon tetrachloride is a thin, transparent, colorless, noninflammable liquid with an odor like chloroform. It is used as a fire extinguisher. Use an air-tight room equipped with a ventilating pipe which leads to a point above the roof. Have a gas-tight valve in the vent pipe. Place the tetrachloride in an open shallow pan at the top of the room. The gas is heavy and travels downward. The liquid evaporates on exposure to air. Use eight pounds per one thousand cubic feet of room space. Keep the temperature of the room at not less than 75°F. Clear the room of gas before opening the door after fumigation. (f) Sulphur dioxide. This is sulphur fumes. The cheapest and simplest method of producing these fumes is the "pot" method. Use broad, shallow pots to assure rapid production of fumes. Use enough pots so that sulphur may be spread to a thickness of not more than two inches. Provide alcohol to start the sulphur burning. Provide a gas-tight room with fresh air inlet and exhaust pipe to outer air above the roof. Have tight valves in each pipe. Use one pound of sulphur to each one thousand cubic feet of room space. There is danger of fire from burning sulphur. Set the pots on brick or metal supports in a large pan of water. These fumes have a bleaching effect and also will tarnish metal. To light the sulphur quickly, sprinkle with alcohol and throw a lighted match in the pot. Keep the room dry–moisture is undesirable during fumigation. Clear the room of gas after the fumigation period before opening room door.