Smelting exposures

Specific chemical exposures and exposure assessment methods relating to studies in the alumina and primary aluminium industry have been reviewed (14). In aluminium smelting, exposure to fluorides, coal tar pitch volatiles, and sulfur dioxide has tended to abate in recent years, but there is insufficient information about other exposures. Published epidemiological studies and quantitative exposure data for bauxite mining and alumina refining are virtually non-existent. Determination of possible exposure-response relations for this part of the industry through improved exposure assessment methods should be the focus of future studies. 

The most significant occupational exposures to zinc would occur during the smelting and refining of zinc ore. The standards for occupational exposure have been estabUshed at a level to prevent the onset of metal fume fever. This temporary condition is caused by excessive exposure to freshly formed fumes of zinc oxide and results in flulike symptoms of fever, chills, headache, muscle pain, nausea and vomiting. 

METAL FUME FEVER Nou-speeifie, self-limiting illness resembling an attaek of influenza eaused mainly by exposure to fumes of zine, eopper, or magnesium and less frequently due to exposure to other metal fumes. Exposures oeeur from molten metals, e.g. in smelting, galvanizing, welding. 

Blood lead levels, urinary lead levels, serum creatinine, blood urea nitrogen (BUN), creatinine clearance (CCT), and NAG were measured in 158 male and 51 female workers in a lead battery factory or a lead smelting plant in Japan (Ong et al. 1987). Controls consisted of 30 professional and laboratory staff members with no history of renal disease or lead exposure. The length of exposure to lead averaged 10.8 8.0 years with a range of 1-36 years. Exposure levels were not available, but indicators of lead body burden in the exposed workers were PbB level = 3.0-80.0 pg/dL and urinary lead level =... 

One case study was identified where a man who had been occupationally exposed to hexachloroethane was treated for a liver tumor (Selden et al. 1989). Exposure had occurred over a period of 6 years as a result of the presence of hexachloroethane in a degassing agent used during aluminum smelting. However, the hexachloroethane reacted at the 700 C use-temperature, releasing a gas that was 96% hexachlorobenzene with small amounts of other chlorinated compounds. Because there was occupational exposure to a mixture of chlorinated compounds rather than just hexachloroethane, it is highly unlikely that the tumor was the result of hexachloroethane exposure alone. Occupational exposure to mineral oil mists for 20 years was also part of the subject s employment history. 

Aerosols of particles larger than 2 pm also cause damage to the upper respiratory system. Arsenic oxides, sulfides, and chlorides are used in a variety of industries, such as manufacturing of colored glass, ceramics, semiconductors, and fireworks and in hide processing. However, upper respiratory exposure to these compounds is most likely to occur in ore smelting industries and in pesticide manufacturing. 

Antimony spots are temporary pustular skin eruptions that afflict workers exposed to antimony compounds. Prolonged or acute exposure results in the build up of antimony in the tissues, especially in liver, kidney, adrenals and thyroid. Antimony(III) is considered to be more toxic than antimony(V) because it is relatively slowly excreted. Long term exposures (up to 28 years) have resulted in pneumoconiosis and emphysema, but even after a few months exposure (5-10 mg m-3) to fumes from antimony smelting pathological symptoms were observed, e.g. rhinitis, pharyngitis and tracheitis.174... 

Additional industrial processes which act as potential sources of occupational exposure to silver include the processing of silver chemicals such as silver nitrate and silver oxide for uses such as photography, and smelting and refining of silver-containing ores (DiVincenzo et al. 1985). 

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