A leaching study was done to determine the leachates of didecyldimethylammonium chloride (DDAC) and borates produced from F2 treated, hem-fir lumber, subjected to simulated rainfall. Taking into account a 1:10 reduction factor, to relate leachate results from single packages to lumber storage yards, the results suggest that the amounts of DDAC and borates would be below those toxic to rainbow trout after 30-120 minutes following onset of heavy rain.