The present study aimed to assess the importance of tannins to the pulmonary toxicity of DB 1/88 cotton dust. A solvent extraction procedure was employed to decrease tannin levels in the dust; however, no difference in pulmonary toxicity was found between the treated and untreated dusts. Dust samples collected from the settling chamber revealed only a partial decrease in tannin content (34 cf 25 mg tannin/g of dust). Further studies are in progress to enhance removal of tannins from the dust and assess toxicity using the guinea pig model.