Document dD9q0w57xB2mzGapbDNY5rybB

or into the pores of a concrete floor, the con tamination may become so great as to necessi tate replacement or sealing of the floor before the plant or laboratory can be safely used again Although it cannot be removed, mer cury can be sealed into such floors by cover ing them completely with an asphalt mastic, preferably after the vapor pressure of the mercury has been reduced by flooding the whole area with a lime sulfur spray To prevent such inconvenience, metallic mercury should be handled over impervious tables or containers with the surfaces de pressed and arranged to drain to a central point Spilled mercury can then be collected and returned to stock A number of volatile mercury compounds are used in seed disinfection Examples are ethyl mercury chloride and phosphate and the corresponding phenyl mercury com pounds These materials are highly toxic When used without adequate enclosure and dust control, they can rapidly produce severe mercurial intoxication These seed-treating compounds are also strong primary skin irri tants and will cause itching, burning, and blistering on direct contact Such irritations heal slowly The type of mercurv intoxication common to industry is characterized by a tremor of the hands, irritation of the mucous membranes of the mouth, excessive flow of saliva, and changes in the personality Poisoning by one of the volatile compounds may be more rapid so that personality changes are not so likely to be seen Inhalation of mercury vapor, usually in very high concentrations, mav produce metal fume fever, which may disappear with no other apparent symptoms, or may be followed by a pneumonitis or other symptoms of mercunalism The ordinary toxic dust respirator does not protect against intoxication by metallic mer cury or by the volatile seed-treating com pounds, since they are in the form of vapor rather than dust A gas mask offers some pro tection, but if enclosure and local exhaust are not possible, the only effective protection is a supplied air respirator See Industrial Data Sheet 203 and Hygtemc Gutde Mesityl oxide is a high-boiling, unsaturated ketone which is thought to be somewhat more toxic than the ketones of lower molecular weights Metal hydrides (primary types) are com pounds of hydrogen and the alkali metals sodium, potassium, lithium, magnesium, cal cium, and strontium Information on the health hazards of metal hydrides is limited Since they react with water to form caustic hydroxides, they are irritating to the eves, skin, and mucous membranes They also re lease a large amount of heat on reaction with the moisture of the skin See Industrial Data Sheet 462 and Hygienic Gutde Methanol (methyl alcohol) poisoning is usually produced bv swallowing the liquid or inhaling high concentrations of vapor in an enclosed place such as a tank The signs of poisoning include headache, nausea, vomit ing, violent abdominal pains, aimless and erratic movements, dilated pupils, sometimes delinum, and such eye symptoms as pain, tenderness on pressure, and occasionally blindness Direct action of the liquid or the vapor on the skin and mucous membranes may pro duce an irritation and inflammation One of the peculiarities of methanol poi soning is its exceptionally severe action on the optic nerve About one-half of all the serious cases of methanol poisoning result in some impairment of vision, which is usually permanent and may vary from dimness or blind spots scattered through the visual field to total blindness See Industrial Data Sheet 407 and Hygienic Guide Methoxychlor (2,2-di [ p-methoxypheny1 ] 1,1,1-tnchloroethane) is a synthetic insecti cide which is closely related to DDT m its action It is, however, about '/ to `/io as toxic as DDT Consequently, the hazard from in halation of the dust or mist of sprays of this insecticide is remote Methoxychlor is not absorbed through the intact skin in significant amounts, and does not seem to have any effect on the central nervous system In animal experiments, con tinued feeding of diets containing methoxy chlor m toxic concentration leads to loss of weight in the animals by their voluntary re striction of food intake and also to fatty m- 1357