Serum Clara cell protein (CC16) and surfactant-associated protein A (SP-A) were measured in a cross-sectional study in 402 firefighters. For the population as a whole, no associations were detected between serum pneumoproteins and smoke exposure. SP-A levels were increased in symptomatic subjects exposed to fire smoke within 2 days before testing. SP-A levels were higher after an inhalation incident ever. CC16 was negatively associated with the number of fires fought in the last 12 months in current nonsmokers. These associations between pneumoprotein levels reiterate the importance of adequate use of self-contained breathing apparatus by firefighters.