Platinum (7440064) industry workers were evaluated to determine the prevalence of occupational asthma in this group. A total of 107 current employees and 29 terminated workers from a single site participated in the baseline study; 74 current and 12 terminated employees participated in the followup study conducted 1 year later. Participants completed questionnaires eliciting pulmonary history and were subjected to skin tests for platinum and three common aeroallergens, IgE determinations, and radioallergosorbent testing (RAST) for platinum-specific antibodies. In addition, a cold air challenge test was given. Platinum salt air concentrations in the refinery, recovery and warehouse areas often exceeded the OSHA standard of 2 micrograms/cubic meter. Most workers in both groups were male smokers; mean employment duration was 70.8 and 61.2 months in the currently employed and terminated group, respectively. Platinum salts skin reactivity was positive in 14% of current workers and 28% of terminated workers. Total IgE was elevated in 52% of terminated workers compared to 23% of current workers; elevated IgE was associated with a positive skin prick test. Platinum skin reactivity was significantly associated with increased RAST binding. Pulmonary symptoms, such as rhinitis, chronic bronchitis, and asthma, were highly prevalent in both groups. Significant airways obstruction was found in 6% of current and 18% of terminated workers. Cold air challenge was positive in a total of 14% of participants, and was significantly associated with positive platinum skin reactivity. At the 1 year followup study, no significant change was noted in skin reactivity; however, a positive cold air challenge test at baseline was associated with skin reactivity conversion at followup.