Abstract
A relatively high incidence of cancer of the skin, especially of the scrotum, due to occupational contact with mineral oil has been observed among shale oil workers and cotton mule spinners and, since the Second World War, among machine operators in the Birmingham region. A study has been made of the factors causing this high incidence and evidence is given that the respiratory and digestive tracts as well as the skin may be affected. The preventive measures are described and the suggestion made that they appear at the present time to be effective.