Mineral oils (untreated and mildly treated).

The carcinogenicity of exposure to untreated and mildly treated mineral oils has been evaluated in numerous studies in a variety of occupations, including metal working, jute processing, mulespinning, newspaper press operation, and other newspaper work. Exposure to mineral oils was consistently and strongly associated with an increased risk of cancer of the scrotum and skin (squamous-cell carcinoma) for many occupations, including metal worker, mulespinner, and jute processor. An analysis of a series of 344 cases of scrotal cancer occurring from 1936 to 1976 in the West Midlands region of England reported that 62% of the men had been exposed to mineral oils. Epidemiological studies (case-control, cohort, and proportional mortality studies) in metal workers have reported excesses of gastrointestinal, sinonasal, and bladder cancer, in addition to skin and scrotal cancer. Some but not all studies (case-control, cohort, and proportional mortality studies) of workers in the printing industry have reported significantly increased incidences of death from cancer of the lung, rectum, buccal cavity, and pharynx. The International Agency for Research on Cancer concluded that there was sufficient evidence for the carcinogenicity of untreated and mildly treated mineral oils in humans (IARC 1984, 1987).