Toxicity tungsten compound

Tungsten dust, powder, and fine particles will explode, sometimes spontaneously, in air. The dust of many of tungstens compounds is toxic if inhaled or ingested. 

NIOSH REL TWA 1 mg(W)/m3 SAFETY PROFILE Moderately toxic by ingestion. When heated to decomposition it emits toxic fumes of POx and Na20. See also TUNGSTEN COMPOUNDS. 

There do not exist any special values for permissible concentrations of hardmetal dust on the work place. Therefore, the MAK values for insoluble W and Co are valid (5mgWC/m and 0.5mgCo/m ). The ITIA (see Section 13.6) is encouraging inducing enhanced activity in regard to acute toxicity tests to be conducted on tungsten compounds including hardmetals (ITIA Newsletter, Jime 1997). 

In the search for non-toxic substitutes for lead pellets, tungsten compounds have risen to the top as a leading best-all-around candidate. Tungsten is much denser than lead and almost three times as dense as steel. This hardness is attractive, but also comes with a brittleness and, before developing it as a non-toxic... 

A considerable difference in the toxicity of soluble and insoluble compounds of tungsten has been reported (58). For soluble sodium tungstate,... 

Orally in rats, the toxicity of sodium tungstate was highest, tungsten trioxide was intermediate, and ammonium tungstate [15855-70-6] lowest (59,60). In view of the degree of systemic toxicity of soluble compounds of tungsten, a threshold limit of 1 mg of tungsten per m of air is recommended. 

Toxicology. The soluble compounds of tungsten are distinctly more toxic than the insoluble forms. 

In comparison to the majority of odier heavy metals, tungsten and most of its compounds possess very low toxicity, if at all. Intoxications occur rarely, almost exclusively by occupational exposure. As treatment in acute poisoning, Dimercaprol (British Antilewisite) may be useful. 

All these findings very clearly demonstrate that only the combination of cobalt with tungsten carbide is a necessary condition to induce severe alveolitis leading to fibrosis. The pulmonary response produced by hardmetal dust is much more pronounced than that caused by pure cobalt or cobalt compounds, while WC alone shows almost no effect. Hardmetal disease is not a consequence of one of the hardmetal components but is a result of interaction between Co and WC particles, producing toxic activated oxygen species, presumably hydroxyl radicals. 

Luckey et al. (1975) indicated that comparison of the toxicity of metal compounds is more useful vhen the LD50 value is expressed in mmol kg instead of the usual mg kg k Metals with small differences in atomic mass can show large variances in specific gravity, which influences the toxicity. For example, tungsten and metavanadate are equally toxic if the LD50 is expressed in mmol kg but vanadate is three-fold... 

Tungsten is a very hard metal which has enormous resistance to heat and is therefore useful for many different industrial purposes. The majority of tungsten is made into cemented tungsten carbide. Only small amounts are present in food and water, and little is known about the toxicity of different forms of tungsten. Tungsten and its compounds are not, however, considered an important health hazard. 

Wenning R and Kirsch N (1988) Tungsten. In Seder HG, Sigel H and Sigel A, eds. Handbook on Toxicity of Inorganic Compounds, pp. 731 — 738. Marcel Dekker, New York. 

Chromium hexacarbonyl is a highly toxic substance by all routes of exposure. The toxic effects are similar to those of molybdenum and tungsten carbonyls. The symptoms are headache, dizziness, nausea, vomiting, and fever. The oral LD50 in mice is 150 mg/kg and in rats 230 mg/kg. The intravenous LD50 in mice is 30 mg/kg. As a hexavalent compound of chromium, it is a carcinogenic substance. 

Tungsten and compounds Few reports of human toxicity. Some saits may reiease aoid upon contaot with moisture. Chronic exposure to tungsten carbide cobait amaigams in the hard-metais industry may be associated with fibrotic iung disease. See cobait. 5 mg/m (insoluble compounds) 1 mg/m (soluble compounds) Elemental tungsten is a gray, hard, brittle metal. Finely divided powders are flammable. 

Caution. Chromium, molybdenum and tungsten hexacarbonyls are volatile solids (Cr > Mo > W) and like all metal carbonyl compounds should be considered to be toxic. tert-Butylisocyanide has a pungent odor, and although many isocyanides are reported to exhibit no appreciable toxicity to mammals, it should still be handled with care. Carbon monoxide is evolved in these reactions and being an odorless, toxic gas, care should be exercised to carry out the reactions in an efficient ventilation hood with the apparatus venting into a well-ventilated region of the hood. 

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