Follow-up of workers from the prefabricated concrete industry after the addition of ferrous sulphate to Danish cement.

Ferrous sulfate has been added to cement manufactured in Denmark, reducing the water soluble chromate content to not more than 2 ppm, since September 1981. A comparison is made between the medical and employment status of a cohort of workers engaged, or who had been engaged, in the manufacture of prefabricated concrete building components in 1981 and in 1987. Workers who had allergic cement eczema in 1981 appeared to show no improvement 6 years after the reduction of chromate in the cement. Improvement was seen, however, in the eczema of those workers with irritant cement eczema. The 1987 study showed that a larger number of chromate-sensitized workers required medical services and topical steroid treatment than did those who were not sensitized to chromate. This difference was statistically significant. The worse medical prognosis of the chromate-sensitized workers could in part be due to the fact that some of these had secondary contact sensitivity to cobalt and rubber chemicals. The chromate-sensitized workers also took earlier retirement. Younger workers with allergic and irritant cement eczema continued to work and their employment status was not influenced by chromate sensitization.