Document G63KmXdGn6BB9NdjeVDNz00Nr

sorbed rapidly and completely so that poi soning will develop from much lower doses It is not even necessary that the compound penetrate deeply into the respiratory system It has been demonstrated experimentally that lead compounds are absorbed rapidly and completely from the nasal passages when they have no chance to go either into the digestive system or deeper into the respira tory system Prevention of lead poisoning is almost en tirely a matter of good housekeeping and dust control To prevent ingestion, food or drinks should not be taken into workrooms where lead compounds are handled The metal is essentially harmless Al though it can be vaporized at high tempera tures, such temperatures are not usually attained in casting, soldering, or heat treating baths Casting and soldering pots should have local exhaust hoods to get nd of lead vapor or lead compounds which may be earned off with volatile fluxes It is at least equally im portant that the surface of the lead be kept free from dross and that the dross container be enclosed under the same hood so that dross can be removed from the pot and the container covered and removed, all under ex haust Likewise, on large soldenngjobs the solder ing operation should be locally exhausted, pnmarily to prevent nose and throat lmtation from acid fluxes More important, the fur naces used for heating the soldenng irons should be exhausted because m these fur naces considerable lead is invariably oxidized Assembly of battery plates and burning on of the connectors should be done on grilletop tables with down-draft ventilation This installation plus regular air sampling to en sure control of contamination, and physical examinations to keep track of lead absorption by employees, can eliminate lead poisoning from battery plants The poisoning produced by inhalation of solid inorganic lead compounds commonly causes symptoms of lead colic and lead anemia Shpple cells or other readily stained cells in the circulating blood are good indi cators of lead absorption, although not so good as the direct measurement of lead con tent of the blood or unne Urinalyses for lead can now be run routinely and cheaply and with sufficient accuracy by polarographic or spectrographic methods Lead tetraethyl and other lead alkyls are likely to be much more rapidly progressive as poisons than the nonvolatile compounds and are much more likely to attack the nerv ous system than to produce gastrointestinal symptoms These effects are probably typical of the volatile lead compounds, none of which is common in industry See Industrial Data Sheet 443 and Hygienic Guide Lethanes --see Thiocyanates (aliphatic). Lindane -- see Hexachlorocyclohexane. Magnesium is one of the light metals used as a construction material In the early days of its industrial use, there were numerous laboratory reports that fine particles of mag nesium, and particularly of magnesium alloys, left in wounds would react with the tissue fluid to produce bubbles of hydrogen gas that would cause severe tissue injury It was stated that when the hydrogen was produced, magnesium hydroxide was also produced and acted as a moderately strong alkali to damage the tissue This reaction is theoretically possible and has been produced in experimental animals by imbedding magnesium powder beneath the skin It was also seen occasionally a num ber of years ago when metallic magnesium clips were tried as substitutes for sutures in experimental surgery Nevertheless, there are no published re ports of such tissue injuries from the indus trial use of magnesium The reason is not known, it may be that such injuries fail to develop or that the hazard is recognized and special care is taken to eliminate particles of the metal and its alloys from industrial in juries The magnesium ion is a normal constituent of a number of tissues, and a certain amount of magnesium in the diet is essential to life Excessive amounts are known to be toxic, and injuries and deaths due to medical use of magnesium salts have been reported There have been no reports of industrial intoxica tion from inhalation of magnesium metal powder or magnesium oxide Inhalation of freshly produced magnesium oxide fumes has caused metal fume fever. 1355