Previous studies in this laboratory have demonstrated that treatment of cotton dust with ethanolic solutions containing NAOH, but not HCl, reduced its pulmonary toxicity in guinea pigs. Since E. agglomerans is a major Gram negative contaminant in cotton dust, and possesses known pulmonary toxicity, the current study investigated the effects of chemical treatment on the pulmonary toxicity of an E. agglomerans cell preparation. Results were in agreement with a previous study on chemically-treated cotton dust in that base but not acid treatment reduced pulmonary toxicity.