SummaryThe herbicide safenerN‐dichloroacetyl‐1‐oxa‐4‐aza‐spiro‐4,5‐decane (AD‐67) is of similar efficiency as the extensively usedN.N‐diallyl‐2,2‐dichloroacetamide (R‐25788) and the structurally related 3‐(dichloroacetyl)‐2,2‐dimethyl‐1,3‐oxa‐zolidine (AD‐2) in reducing EPTC [S‐ethyl‐N,N‐dipropyl (thiocarhamate)] injury to maize (Zea maysL. cv. KSC 360). EPTC treatment produces growth retardation and deformities and inhibits CO2fixation. It does not reduce epicuticular lipids appreciably but affects wax arrangement on the leaf surface. When EPTC is applied together with one of these safeners, these injuries are not observed. All three safeners act similarly. Each prevents the herbicide‐induced aggregation of epicuticular wax of maize, thereby protecting the plants against the formation of areas where the underlying cuticle l