Of several aerosol formulations of 3 synthetic pyrethroids, S-2539 Forte, resmethrin, and bioresmethrin, the 2per thousand formulation was most effective for the disinsection of passenger space aboard jet aircraft; the 1.2. per thousand and 0.3per thousand formulations were less effective. Break-off tip aerosol unites gave good dispersal, but these limited production can showed slight variability in the rate of release.