Carbon Monoxide Exposures from Propane-Powered Floor Burnishers Following Addition of Emissions Controls

Abstract

Previous published work by this author suggests that propane-powered floor burnisher use represents a potentially serious health hazard from carbon monoxide exposures, particularly for susceptible individuals. This earlier study, which assessed custodians' exposures to carbon monoxide during burnisher use, was repeated using burnishers retrofitted with emission controls consisting of self-aspirating catalytic mufflers and computerized air/fuel monitors and alarms. Realtime carbon monoxide detectors with datalogging capabilities were placed on the burnishers in the breathing zones of operators during burnisher use. Carbon monoxide levels were recorded every 30 seconds. Ventilation and physical characteristics of the spaces of burnisher use were characterized, as were burnisher maintenance practices. Thirteen burnishing events were monitored under conditions comparable to previously published monitoring. All carbon monoxide exposures were well below even the most conservative recommended limits from the American Conference of Governmental Industrial Hygienists. Average maximum peak exposures were reduced 91 percent, from 235 ± 106 ppm before emission controls to 20 ± 14 ppm. Average maximum short-term 15-minute exposures and mean time-weighted average exposures during burnisher use were reduced 96 percent, from 136 ± 51 to 6 ± 4 ppm and from 125 ± 47 to 5 ± 3 ppm, respectively. Potential failures of the emission controls were also identified and included air filter blockage, spark plug malfunction, and faulty alarm function design. While the addition of emission controls significantly reduces the carbon monoxide exposure risk, the burnishers are still capable of producing excessive carbon monoxide emissions under these aforementioned conditions, and carbon monoxide may accumulate to unsafe levels when burnishers are used in areas with inadequate ventilation. Recommendations for safe use are provided. Use of electric burnishers is advised if guidance is not strictly followed or later proves inadequate.