Health of workers in chromate producing industry : a study.

  • United States. Public Health Service. Division of Occupational Health
Date:
1953]
Catalogue details

Licence: Public Domain Mark

Credit: Health of workers in chromate producing industry : a study. Source: Wellcome Collection.

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    ABSTRACT—SUMMARY This report presents the clinical and environmental findings of an investi- gation to determine the present health status of chromate workers and to evaluate the effects of the working environment on their health. Environmental investigations were made in six plants which are directly involved in the manufacture of chromates and bichromates from chromite ore. These plants are located in the states of Maryland, New Jersey, Ohio and New York and employ a total of approximately 1,200 persons. The same basic raw material, chemical grade chromite ore (FeO:Cr203), is being processed by all of the plants. Basically, the manufacturing process in all of the plants is the same. Briefly, it consists of roasting the finely ground chromite ore with soda ash or with a soda ash and lime mixture to produce a water soluble chromium compound, sodium chromate, which is converted by acidification and crys- tallization into crystalline sodium bichromate. Soluble materials other than chromates and bichromates occur in the chromate and bichromate liquors. By-products such as alumina, sodium sulfate, and sodium vanadate may be recovered from these liquors. Approximately 1,600 samples of airborne materials were collected with the standard impinger and the midget impinger. About 100 material and settled dust samples were also analyzed. It was found that the dry-end processes generate dusts containing chromite ore, soda ash, roast, residue and sodium chromate. Sodium bichromate and sodium sulfate are usually found associated only with the wet-end processes. An appreciable portion of the total chromium was found to be present in an acid soluble-water insoluble state, indicating the presence of a form or forms of chromium which are dissimilar from either insoluble chromite ore or water soluble, hexavalent chromium. These acid soluble-water insoluble chromium compounds were found to be associated especially with roast or residue processes, although they were noted in many other parts of the chromate plants. The greatest weighted average exposure to chromium-bearing dusts occurred in the dry end with maximum mean exposure of 1.07 milligrams of total chromium per cubic meter of air for mill room laborers. The greatest weighted average exposure (0.17 mg Cr/m*) to hexavalent chromium occurred among potash production operators. Occupations with average exposures greater than 0.10 mg of water soluble hexavalent chromium per cubic meter of air included residue mix operators, crane operators, leach operators, sulfate recovery operators and centrifuge operators. The two occupational groups which process residue had the greatest average ex- posure, excluding tanning compounds, to acid soluble-water insoluble chromium. These groups are residue mix operators (0.17 mg Cr/m?*) and residue mill operators (0.15 mg Cr/m?). A medical examination was made of 897 chromate workers. Among this group were 10 persons who were considered as having bronchiogenic car-
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