Heart Disease Mortality among Bridge and Tunnel Officers Exposed to Carbon Monoxide.
Stern-FB; Halperin-WE; Hornung-RW; Ringenburg-VL; McCammon-CS
A retrospective study was conducted of 5529 New York City bridge and tunnel officers to determine the effect of occupational exposure to carbon-monoxide (630080) (CO) with specific reference to heart disease mortality. Continuous monitoring of CO within the tunnels operated by the Triborough Bridge and Tunnel Authority began in 1940. In 1961 the 24 hour average CO concentrations inside the tunnels were 53 parts per million (ppm) in the summer and 49ppm in the winter with peaks of 200 to 300ppm in the summer and 100 to 200ppm in the winter. Monitoring in 1970 indicated CO levels of 63ppm in tunnel toll booths and 13ppm in bridge toll booths. In 1977 ventilation equipment which had been installed was linked to continuously reading CO monitors. Peak 1981 CO exposures in the traffic lanes of both the tunnel and bridge and on the tunnel catwalk were often greater than 100ppm and sometimes surpassed 400ppm. Arteriosclerotic heart disease (ASHD) was the cause of death in 61 former tunnel officers as compared to the expected number of 45. A Cox proportional hazards model was used to compare the risk of mortality from ASHD among tunnel officers to the less exposed bridge officers. While there was a significant association between exposure and age, no association of ASHD was noted with length of exposure. After cessation of exposure the elevated risk of ASHD among tunnel officers as compared to bridge officers declined, usually within as short a time period as 5 years. According to the authors, present research shows that CO may be important in the pathophysiology of cardiovascular mortality associated with cigarette smoking.
NIOSH-Author; Cardiovascular-system-disorders; Air-quality-monitoring; Air-sampling; Tunnel-workers; Automotive-exhausts; Automotive-emissions; Toxic-gases; Epidemiology;
NTIS Accession No.
Division of Surveillance, Hazard Evaluations, and Field Studies, NIOSH, Cincinnati, Ohio, 34 pages, 53 references