Chromium occupational exposure

The U.S. Public Health Service (USPHS 1993) recommends that occupational exposure to hexavalent chromium compounds should not exceed 1 pg/m3 air for a 10-h workday and 40-h workweek because all hexavalent chromium compounds are potential carcinogens. Other recommendations include more research on ... 

National Institute for Occupational Safety and Health Criteria for a Recommended Standard. . . Occupational Exposure to Chromium(VI). DHEW (NIOSH) Pub No 76-129, Washington, DC, US Government Printing Office, 1975... 

OSHA regulates chromium levels in the workplace air. The occupational exposure limits for an 8-hour workday, 40-hour workweek are 500 pg chromium/m3 for water-soluble chromic (chromium(HI)) or chromous [chromium(II)] salts and 1,000 pg chromium/m3 for metallic chromium (chromium(O)), and insoluble salts. The level of chromium trioxide (chromic acid) and other chromium(VI) compounds in the workplace air should not be higher than 52 pg chromium(VI)/m3 for any period of time. 

Occupational exposure to chromium(VI) and/or chromium(III) in other chromium-related industries has also been associated with respiratory effects. These industries include chromate and dichromate production, stainless steel welding, and possibly ferrochromium production and chromite mining. 

Gastrointestinal Effects. Gastrointestinal effects have been associated with occupational exposure of humans to chromium compounds. In a report of two cases of acute exposure to "massive amounts" of chromium trioxide fumes, the patients complained of abdominal or substernal pain, but further characterization was not provided (Meyers 1950). 

Occupational exposure to chromium(III) or chromium(O) does not appear to be associated with renal effects. No renal impairment based on urinary albumin, retinol binding protein, and renal tubular antigens was found in 236 workers employed in the ferrochromium production industry where ferrochromite is reduced with coke, bauxite, and quartzite. The mean airborne concentration of chromium in various sample locations was 0.075 mg chromium(III)/m3 chromium(VI) was below the detection limit of 0.001 mg chromium(VI)/m3 at all locations (Foa et al. 1988). Workers employed in an alloy steel plant with a mean exposure of 7 years to metallic chromium at 0.61 mg chromium(0)/m3 and to other metals had normal urinary levels of total protein and p2-microglobulin, enzyme activities of alanine-aminopeptidase, N-acetyl-P-D-glucosaminidase, gammaglutamyl-transpeptidase, and P-galactosi-dase (Triebig et al. 1987). In boilermakers exposed to chromium(O), no increase in urinary levels of... 

No elevated levels of DNA strand breaks or hydroxylation of deoxyguanosine in lymphocytes were found in 10 workers occupationally exposed in the production of bichromate when compared with 10 non-occupationally-exposed workers at the same facility Gao et al. (1994). From general background monitoring levels of chromium(VI), exposures were estimated to be between 0.001 and 0.055 mg/m3. 

Occupational exposure to chromium(VI) compounds in a number of industries has been associated with increased risk of respiratory system cancers, primarily bronchogenic and nasal. Among the industries investigated in retrospective mortality studies are chromate production, chromate pigment production and use, chrome plating, stainless steel welding, ferrochromium alloy production, and leather tanning. 

In conclusion, despite limitations of some studies, occupational exposure to chromium(VI) in the chromate production industry is associated with increased risk of respiratory cancer, but improvements in the production process and industrial hygiene appear to have reduced the risk over the past 30-40 years. 

Respiratory Effects. Occupational exposure to chromium compounds results in direct contact of mucocutaneous tissue, such as nasal and pharyngeal epithelium, due to inhalation of airborne dust and mists of these compounds. Such exposures have led to nose and throat irritation and nasal septum perforation. Because exposure is to airborne chromium, studies noting these effects are described in Section 2.2.1.2. 

Dermal Effects. Occupational exposure to airborne chromium compounds has been associated with effects on the nasal septum, such as ulceration and perforation. These studies are discussed in Section 2.2.1.2 on Respiratory Effects. Dermal exposure to chromium compounds can cause contact allergic dermatitis in sensitive individuals, which is discussed in Section 2.2.3.3. Skin burns, blisters, and skin ulcers, also known as chrome holes or chrome sores, are more likely associated with direct dermal contact with solutions of chromium compounds, but exposure of the skin to airborne fumes and mists of chromium compounds may contribute to these effects. 

Longer-term occupational exposure to chromium compounds in most chromium-related industries can cause deep penetrating holes or ulcers on the skin. A man who had worked for a few months in a planographic printing establishment, where he handled and washed sheets of zinc that had been treated with a solution of ammonium dichromate, had skin ulceration on both hands (Smith 1931). 

Occupational exposure to chromium(VI) primarily as mist/aerosol can result in respiratory effects. Animal studies have reported respiratory effects following exposure to chromium(VI) or chromium(III) mists and particulates. Exposure to chromium in ambient air is mainly to chromium(III) adhered to dust particles (see Section 5.4.1). The possibility that inhalation exposure to chromium in the environment, from industrial sources, or at hazardous waste sites could result in respiratory effects cannot be ruled out. 

Preussmann 1975 MacKenzie et al. 1958). It is possible that occupational exposure to chromium compounds could change the hematological profiles of humans, but hematological effects due to exposure in the environment or at hazardous waste sites seems less likely. 

Although skin contact with chromate salts may cause rashes, untreated ulcers or sores (also called chrome holes) on the skin can be a major problem because they can deeply penetrate the skin with prolonged exposure. For example, in an early case of a tannery worker, the penetration extended into the joint, necessitating amputation of the finger (Da Costa et al. 1916). However, chrome sores heal if exposure is discontinued, leaving a scar. Chrome sores are more often associated with occupational exposure to chromium(VI) compounds. Although chrome sores are more likely associated with direct dermal contact with solutions of chromates, exposure of the skin to airborne fumes and mists of... 

Biological monitoring has been used to relate serum and urine chromium levels to occupational exposure levels. A statistically significant (r=0.95, p<0.001) relationship between total chromium exposure and urinary chromium concentrations at the end of the workday were observed in five welders exposed to chromium(VI) compounds. The urinary chromium concentrations of 40-50 pg/L immediately after work... 

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