Change in cement manufacturing process, a cause for decline in chromate allergy?

Abstract

Hexavalent chromate in cement is the commonest cause of allergic contact dermatitis, especially among construction workers. Over the past decades, there has been a general decline in the prevalence of chromate allergy among construction workers. We suspect that a change in the constituents of cement, resulting in the lowering of hexavalent chromate, contributed to the decline. Slag (free from hexavalent chromate) from the iron-quenched, blast furnace process has been used as a substitute for clinker (which contains high hexavalent chromate) in manufacturing cement. As a result, the slag has diluted the hexavalent chromate content of cement. Our analytical study showed that slag is free from hexavalent chromate and that the hexavalent chromate of clinker ranged from 6-17 micrograms/g. Substituting slag for clinker resulted in dilution of hexavalent chromate in the cement. The hexavalent chromate content of cement declines proportionately with increasing proportion of slag, e.g., a cement containing 5% slag has a total hexavalent chromate concentration of 17.5 micrograms/g, whereas increasing the proportion of slag to 60% reduced the hexavalent chromate content to 7.1 micrograms/gm in the same cement.

Occupational skin disease in the construction industry

“…In 1981, the prevalence of chromium allergy in construction workers was reported to be 5·5% in Singapore and 8·9% in Denmark 25 . The prevalence decreased significantly in the small Danish database from 8·9% to 1·3% after use of cement with reduced levels of chromium VI by adding ferrous sulphate to cement was introduced 26 .…”

Chromium

“…Over the last several decades, the prevalence of allergic contact dermatitis in cement workers decreased as a result of the reduction of hexavalent chromate in cement. 96 Case reports have associated the development of occupational asthma in chromium-sensitized workers with the following type of exposures: chromic acid vapors, 77,97 metal plating with chromium, 78 chromate spray paint, 98 zinc chromate primer paint, 97 and Cr (VI) fumes from stainless steel welding. 99 Inhalational challenges of chromates in chromium-sensitized workers produced angioedema, erythema, pruritus, cough, wheezing, and bronchospasm.…”

Evaluation of metalworking fluid exposure and dermatitis among rifle barrel manufacturing employees.

“…For example, the addition of ferrous sulfate to cement to reduce the hexavalent chromium content has been effective in reducing occupational allergic contact dermatitis in Europe [Goh and Gan 1996]. Protective gloves can reduce or eliminate skin exposure to hazardous substances if used correctly, but may actually cause or worsen hand dermatitis (by permeation and penetration) if selected poorly and used improperly (by contamination) [Foo et al 2006].…”