Occupational lung diseases must be defined accurately for clinicians who diagnose and treat these disorders, and for government and legal agencies that must decide on causation and determine disabilities (1). The definitions must be an amalgam of information from physicians, scientists, and industrial hygienists, who can provide different perspectives from their clinical, epidemiologic, and exposure data.
The definition of byssinosis (an occupational hazard for workers with cotton, flax, hemp, or sisal fiber), depends in part on symptoms associated with work-week exposure. The symptoms are graded in relation to degree of persistence with re-exposure to the offending fiber: grade 1 is