Carbon Monoxide Uptake by Inspectors at a United States-Mexico Border Station

Collection of expired-air carbon monoxide (CO) samples was utilized to examine inspectors on the United States-Mexican border to determine if significant increases in carboxyhemoglobin (COHb) occur. Twenty-six border inspectors were categorized as to smoking habits and work shift CO exposures. Employees not actively engaged in car inspection duties constituted the control group. Following shifts when particularly high ambient CO levels persisted, significant increases in COHb were noted in both smokers and non- smokers. Controls did not exhibit significant alterations in COHb levels. The hazards of such COHb elevations to exposed individuals are discussed in light of recent evidence of a lack of threshold for cardiovascular and central nervous system effects.