Several typical bales of cotton of equivalent grade from three different growing, locations were selected from commercial cotton samples. Bales from the Mississippi Delta, Texas High Plains, and California San Joaquin Valley were processed in a model card room using commercial manufacturing practices. Human subjects were given six-hour exposures to dust generated by the card. Preshift and postshift spirometry was performed on the subjects to determine pulmonary response. Decrement in FEV(1) to dusts from the experimental cottons was compared.