Data were collected on sex, race, smoking, age, atopic status, degree of bronchoconstriction in response to cotton dust exposure as measured by Monday shift change in FEV1, length of employment, past and current exposure to cotton dust, job type, grade of cotton processed, geographical location of the plant, and bacterial contamination of the cotton. Lung function tests were conducted annually for five years by obtaining pre- and post-shift spirometric data. Data were available on the company's dust measurements for the past ten years. Dust measurements were made during the study to reconstruct a complete exposure profile for the various job titles in each production area during the total period of employment of workers participating in the study.