Carbon Monoxide Exposure of Concrete Finishers

Abstract

The use of small internal combustion engines is common in construction. The use of these engines in enclosed spaces, however, has led to hospitalizations and fatalities. Concrete finishers regularly use gasoline-fueled trowel machines in enclosed spaces. This study was undertaken to determine the exposure of concrete finishers to carbon monoxide during the finishing of basements in new home construction. The effect on exposure of basement size, area open to the outside, and use of propane heaters during troweling was also investigated. Sampling was performed during the finishing of concrete floors in 20 basements. Machine troweling of basement floors can lead to an overexposure to carbon monoxide. The ceiling and short-term exposure limits of the American Conference of Governmental Industrial Hygienists, the National Institute for Occupational Safety and Health, and the Ontario Ministry of Labour were exceeded more often than were the 8-hour time-weighted average limits. The exclusive use of a full-shift or 40-hour averaging period for carbon monoxide exposure measurements may underestimate serious health risks. No relationship between basement volume and exposure, or between area open to the outside and exposure, was found. The use of propane heaters during troweling significantly increased exposure. Methods to control this exposure include using electrical power, catalytic converters, ventilation, and respiratory protection. More research is required to find the most practical solution.