Abstract: Chloromethyl methyl ether and di(chloromethyl) ether contaminants are removed from air in laboratories, industrial plants and other locales wherein chloromethyl ether (more accurately called chloromethyl methyl ether) and bis-chloromethyl ether are used for various purposes. Silica gel and/or activated alumina are employed for removing the chloromethyl ethers either with or without other contaminants from the gaseous atmosphere wherein they occur. The absorption of the ethers on the silica gel or activated alumina is carried out under conditions of temperature that have been found to result in the hydrolytic decomposition of these chloromethyl ethers, apparently by virtue of catalytic action occurrng on the surface of the silica gel or activated alumina.