Document 06VpR8B3ZrO9yVMn3w8vJzQMO

38--Industrial Toxicology 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 respiratory 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 Although it can be vaporized at high temperatures, such temperatures are not usually attained in cast ing, soldering, or heat treating baths Casting and soldenng pots should have local exhaust hoods to get nd of lead vapor or lead compounds which may be carried off with volatile fluxes It is at least equally important 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 exhaust Likewise, on large soldenng jobs 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 furnaces considerable lead is mvanably oxidized Assembly of battery plates and buming-on of the connectors should be done on gnlle-top tables with down-draft ventilation This in stallation plus regular air sampling to ensure control of contamination, and physical ex aminations to keep tiack 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 ane mia Stipple 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 urine 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 nervous system than to produce gastrointestinal symp 1152 toms These effects are probably typical of the volatile lead compounds, none of which is common in industry Lethanes--see Thiocyanates (aliphatic). Lindane--see Hexachlorocyclohexane. M Magnesium is one of the light metals used as a construction material In the early days of its industrial use, there were numerous lab oratory 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 expenmental animals by imbedding magnesium powder beneath the skin It was also seen occasionally a number of years ago when metallic magnesium clips were tried as substitutes for sutures in expen mental surgery Nevertheless, there are no published reports of such tissue injunes from the industrial use of magnesium The reason is not known, it may be that such injunes fail to develop or that the hazard is recognized and special care is taken to eliminate particles of the metal and its alloys from mdustnal injuries The magnesium ion is a normal constituent of a number of tissues, and a certain amount of magnesium in the diet is essential to hfe 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 intoxication from inhalation of magnesium metal powder or magnesium oxide Inhalation of freshly produced magnesium oxide fumes has caused metal fume fever, sim ilar to the better known "zinc chills" or "zinc shakes" caused by inhalation of freshly formed zinc oxide fumes Heavy exposure to magnesium oxide is irri tating to the eyes, nose, and throat, but the material is not a severe primary untant Finely powdered magnesium is a fire haz-