concentrations of fumes for particular elements (Fe,
Mn, Ni, F, Cr VI, Cr III) adopting the principle of
their cumulative toxic effect. The evaluation of combined
occupational exposure (figs 7-9) allowed us to
ascertain that maximum allowable concentrations
(MAC) values were exceeded in 42-5% ofMMA/SS
welders (n = 72). Individual welders' combined
exposure to the elements in fumes was 24 times the
admissible value for Cr VI, 17 times for Ni and three
times for Mn in plant A (fig 7). The hygienic
standards for various Cr forms, mandatory in some
other countries, were exceeded for total Cr VI and
soluble Cr VI in 23-25% of results and for soluble Cr
VI in 5% of results, whereas no form of Cr III
exceeded hygienic standards (table 5).