To date, the most effective method of detoxifying cotton dust, as assessed by measurement of pulmonary function in guinea pigs, has been treatment of cotton dusts with ethanolic solutions containing NaOH. The current study assessed the efficacy of several NaOH treatments. DB 01-88 cotton dust was first treated with HCl in ethanol, followed by an ethanolic solution of NaOH. This treatment did not reduce the pulmonary toxicity. A temperature modification in the standard treatment with NaOH also failed to decrease pulmonary toxicity. However, DB 01-88 cotton dust treated five times by the standard NaOH treatment was rendered nontoxic as had been found previously with another cotton dust (DB 11-82). Treatment of dust with ethanolic NaOH at 65 C remains an effective method for detoxifying cotton dust.