Bulk cotton dust from the Memphis area was treated with a variety of polar solvents with and without additives included 95% endotoxin levels. The polar solvents included 95% ethanol, methanol, 87.7% isopropanol, dimethylformamide, dimethylsulfoxide, and pyrogen-free water. The additives included mineral acids and bases, organic acids and bases, and detergents. Endotoxin levels were, determined by Limulus amebocyte lysate gelation. Dimethylsulfoxide without additives, 95% ethanol with sodium hydrochloric acid, or hydrochloric acid, and pyrogen-free water with sodium hydroxide or hydrochloric acid were most effective in reducing endotoxin levels in the cotton dust.