The sensitivity of male Drosophila-melanogaster to low concentrations of gaseous 1,2-dibromoethane (106934) (DBE) was evaluated. The sex linked recessive lethal test detected mutagenicity at all exposure concentrations of DBE ranging from 0.2 to 2.0 parts per million (ppm). The lowest effective exposure for spermatozoa was 18ppm for one hour or 0.25ppm for 72 hours, while in spermatids, the lowest effective exposure of 2.3ppm for an hour or compared to spermatozoa. Spermatids and spermatocytes were about 10 to 20 times more sensitive to germ cell differences than spermatozoa. DBE concentrations below 60ppm for a one hour exposure produced a linear dose relationship for all three sperm cell types. The authors conclude that Drosophila provide a detection method for mutagenicity of very low concentrations of industrial, agricultural, and environmental air pollutants.