Document b5R3g0pMObXoQM3rX4jQ9KLro

ELEMENTS OF INDUSTRIAL TOXICOLOGY the slrrn in significant amounts, and does not seem to have any effect on the central nervous system. In animal experi ments, continued feeding of diets containing methoxychlor in tome concentration leads to loss of weight in the animals by their voluntary restriction of food intake and also to fatty infiltration of the liver in the manner of the chlorinated hydrocarbons. Methyl acetate is widely used as a low balling solvent m the perfume, cosmetic, and paint industries. It is imtatmg to die mucous membranes of the eyes and the respiratory passage Animal studies indicate that there may he general poisoning and long-lasting afteref fects when methyl acetate is mhaled in con centrations below that which produces nar cosis. If exposure is senous, pulmonary edema and hemorrhages may occur, along with injury to the blood vessels. Symptoms of exposure are eye inflamma tion, nervousness, chest tightness, heart palpitation, exhaustion, and shortness of breath. See Hygienic Guide. Methyl alcohol--see Methanol. Methyl bromide is widely used as a fire extinguishing agent and as a fumigant. An efficient fire extinguishing material, it has been msmiled m fixed systems in a num ber of aircraft and naval vessels, particu larly m Groat Bntam where several cases of poisoning have been reported. Numerous poisoning cases also have occurred in die use of material m fumigation and m industry. The minimum concentrations which will produce mild poisoning are low. One in vestigator recorded 22 cases of skin irrita tion and 31 cases of mild systemic effects among 90 persons working during a twoweek period at the filling and sealing of methyl bromide ampules Concentrations of airborne methyl bromide were regularly de termined around this operation and were generally below 35 ppm. The skm lesions resulted from exposure to small quantities of the liquid while it was being handled under a hood. The liquid is a strong skm irritant Skm contact can produce severe dermatitis, blis ters, itchmg, and slow-healing burns No particular irritation is caused by breathing methyl bromide in quantities suf ficient to produce systemic toxicity. The effects are not seen for a few hours to two or three days after the exposure In mild systemic poisoning the most common com plaints are lade of appetite, nausea, and headache. Dizziness and blurring of vision are also common In more severe poisoning, there may be hallucinations and slurring of speech. Methyl bromide is also a powerful irri tant to the lungs and in severe poisoning will produce secretion of liquid into the lungs and dins interfere with breathing See Halogennted hydrocarbons and Hy gienic Guide. Methyl CeDosolve--see Ethylene glycol monomethyl ether. Methyl chloride has been widely used as a refrigerant and a number of cases of se vere intoxication have occurred from small leaks m large refrigeration systems There have also been a number of Industrial cases The effects follow a fairly standard pattern with dizziness, weakness, blurred vision, loss of muscular coordination, and drowsi ness m all instances Loss of appetite, dis turbances of sleep, end confusion are also common oomplamts. Methyl chlonde is retained to some ex tent m the brain, heart, liver, stomach, spleen, kidneys, muscle, and blood, and regu larly produces edema of the lungs, degener ation of die liver and kidneys, and some damage to the heart. The mechanism of its action, however, is not yet understood It possesses no warning properties and smee those who are becoming intoxicated may become so confused that they are not able to protect themselves, this material most be handled with the greatest of care Since methyl chloride is a low-boiling liquid normally handled under pressure, se vere skm injuries--freezing and blisters-- may occur if the skin is brought mto con tact with a leak. See Balogenated hydrocarbons and Hy gienic Guide. Methyl chloroform (1,1,1-trichIoroethane) closely resembles carbon tetrachloride m its solvent action and its rate of evaporation, but is much less toxic. Like trichloroethy lene it tends to attack die central nervous 40-41