Abstract
Eighty milliliters of carbon monoxide (CO) or 80 ml of air was administered doubleblind to 50 adults (32 men, 18 women). Blood carboxyhemoglobin (COHb) levels increased by 3.4% in those receiving CO. Brake reaction time, night vision, glare vision, glare recovery, hand-steadiness, and depth perception all showed small and individually insignificant deterioration in the group receiving CO; grouping data in a nonparametric analysis, the performance difference became significant (P < .005). During operation of a driving simulator, the CO-exposed group showed a highly significant deficit in “careful driving” skills (P < .005), with a statistically insignificant facilitation of emergency-type movements. Since a 3.4% increase of COHb level is sufficient to prejudice safe driving, there is a need to revise the permitted eight-hour industrial CO exposure level of 50 ppm.