End-expiratory carbon monoxide levels as an estimate of passive smoking exposure aboard a nuclear-powered submarine.

Passive smoking is the involuntary inhalation of tobacco smoke by nonsmokers. The purpose of this study was to estimate the degree of passive smoking exposure sustained by smokers and nonsmokers in a nonventilated submarine through the measurement of end-expiratory carbon monoxide (EECO) levels. The initial and final EECO levels were compared for both smokers and nonsmokers. A simple linear regression equation was then used to compare the initial EECO levels in smokers (and their daily cigarette use) with the postsubmergence EECO levels in nonsmokers. Our results showed the postsubmergence EECO levels in the nonsmoking crew members approximated the initial EECO levels in crew members who smoked 21 cigarettes per day. Nonsmokers in a submerged submarine are exposed to significant levels of CO. Future studies are needed to determine the health consequences of this significantly increased level of exposure in nonsmokers.