Spirograms were made in 103 chemical workers, 72 of whom had been exposed for years to chloromethyl ethers to various degrees. The end-expiratory flow rate was below 60% of predicted in one-third of exposed men compared to only 3% of unexposed men. Smoking was a confounding factor. In 49 current cigarette smokers consuming less than one pack per day, the data suggested a dose-response relationship between chemical exposure and the frequency of low end-expiratory flow rate.