Mortality of workers on an isopropyl alcohol plant and two MEK dewaxing plants

An historical prospective study was undertaken of 262 men who had worked on an isopropyl alcohol plant and 446 men who had worked on two MEK dewaxing plants. All of the former have been traced, and only one man from the latter group was lost to follow-up. These studies linked occupational records with cause of death data for those who had died; the average follow-up was 15.5 years for the IPA plant workers and 13.9 years for those on the MEK dewaxing plants. For the IPA workers the observed deaths (26) were slightly above the expected (23.6), and there was a non-significant excess of deaths from neoplasms (0 = 9, E = 6.19). One person died from nasal cancer (E = 0.02, p = 0.017); though based on small numbers this finding is unlikely to be due to chance and agrees with the original hazard. For those who had worked on the MEK dewaxing plants the observed deaths (46) were below the expected (55.51) and there was also a slight deficiency of deaths from neoplasms (0 = 13, E = 14.26). When the seven sites of malignancy, which had been examined in a recent American study, were compared there were significantly more deaths from buccal cavity and pharynx cancers (0 = 2; E = 0.13; p = 0.008) and significantly fewer from lung cancer (0 = 1; E = 6.02; p less than 0.045). After reviewing the American and present results, it was concluded that there is no clear evidence of a cancer hazard in these workers, though further follow-up of larger numbers is necessary for a more precise estimate of the confidence limits of these findings.