The cigarette factor in lung cancer due to chloromethyl ethers.

In a prospective study of 51 men who had moderate to heavy cumulative exposure to chloromethyl ethers, 11 developed lung cancer in a ten-year perod. The risk was higher in men who were not smoking cigarettes at the start of observation than in those who were. This difference was even more impressive when examined in relation to the risks of lung cancer by smoking habit in the general population. The data suggest that continued cigarette smoking entailed a factor which partially inhibited the carcinogenic effect of chloromethyl ethers.