Agriculture today is dependent on the application of a great number of chemicals, many of them toxic, so that the possibility arises of contamination of food and environment. Many efforts are therefore made to find novel methods of achieving better control over the release of these chemicals, so that the desired effects are attained by application of smaller amounts. Release of desmetryn into the gas phase from films of ethylene-vinyl acetate copolymer, in which the herbicide was incorporated for special agricultural applications, was investigated for comparison with release into water and under outdoor conditions. It could be shown that the rate of release of the active chemical into the gas phase was negligible compared with that into water and only slightly dependent on temperature in the range 0-75 degree C.