In all these studies, sulfuric acid mists were the commonest exposure, and positive exposure-response relationships were seen in two of the studies. Additional supporting evidence was provided by one cohort study in the soap manufacturing industry in Italy, which showed an increased risk for laryngeal cancer. Studies of three US cohorts and one Swedish cohort in the phosphate fertilizer manufacturing industry showed excess lung cancer, but there was potential confounding from exposure to radon decay products in some cohorts. No data were available to the Working Group. 5.4 Other relevant data Acid mists containing particles with a diameter of up to a few micrometers will be deposited in both the upper and lower airways.
Asthmatics appear to be at particular risk for pulmonary effects.
Significant increases in the incidences of sister chromatid exchange, micronucleus formation and chromosomal aberrations in peripheral lymphocytes were observed in a single study of workers engaged in the manufacture of sulfuric acid. In cultured mammalian cells at pH 6.7 or below, cell transformation, gene mutation and chromosomal aberrations were induced. Mitotic abnormalities were induced in sea urchins and clastogenic effects in plants. Gene conversion was induced in yeast cells. No point mutation was observed in fungi, yeast or bacteria.