<Tr> <Td> </Td> <Td> This section needs expansion . You can help by adding to it . (August 2011) </Td> </Tr> <P> DEET was developed in 1944 by Samuel Gertler of the United States Department of Agriculture for use by the United States Army, following its experience of jungle warfare during World War II . It was originally tested as a pesticide on farm fields, and entered military use in 1946 and civilian use in 1957 . It was used in Vietnam and Southeast Asia . </P> <P> In its original form known as "bug juice", the application solution for DEET was composed of 75% DEET and ethanol . Later, a new version of the repellent was developed by U.S. Army and the USDA . This incarnation consisted of DEET and polymers that extended the release of the DEET and reduced its evaporation rate . This extended - release application was registered by the EPA in 1991 . </P> <P> A slightly yellow liquid at room temperature, it can be prepared by converting m - toluic acid (3 - methylbenzoic acid) to the corresponding acyl chloride, and allowing it to react with diethylamine: </P>

What is deet and why is it bad