In tests of fire-retardant chemicals as an aid in controlling Douglas-fir slash fires, one-third as many spot fires started in retardant-treated areas as in untreated areas. Rate of fire spread in lightly treated areas inside the slash blocks was one-tenth that in adjacent areas. Chemical application cost from $3 to slightly more than $4 per acre of slash burned. This cost may be offset by manpower savings due to safer, more manageable burns.© Society of American Foresters, Bethesda, MD. Abstract reproduced by permission.