Carbon Monoxide Exposure Potential Associated With the Use of Recreational Watercraft

Carbon monoxide (CO) is a colorless and odorless gas generated from incomplete combustion of hydrocarbon-based fuels. Exposure to elevated CO concentrations can cause an array of health problems or even death. Of increasing concern are CO-related poisonings and fatalities associated with recreational watercraft. From 2005–2018, there were 78 known deaths of people due to CO associated with the use of recreational watercraft in the U.S. The incidence, however, is likely higher due to many CO poisoning-related deaths being inaccurately attributed to drowning instead of CO poisoning. To examine the significance of this public health hazard, a range of plausible exposures were characterized by measuring instantaneous CO concentrations at 17 sampling locations on or near the stern of four recreational boats. Observed CO concentrations were highest in samples proximal to the engine exhaust manifold, with maximum concentrations for the four boats being 42,600 ppm, 2,550 ppm, 6,100 ppm, and 3,700 ppm, respectively. Continuous CO monitoring was performed at a fixed location near the passenger seat in the back of each boat. Comparing our monitoring results with thresholds set by the U.S. Environmental Protection Agency, National Institute for Occupational Safety and Health, and World Health Organization demonstrates that many CO concentrations exceed or nearly exceed established exposure thresholds. Thus, environmental health and public safety professionals must remain aware of this hazard and examine administrative and engineering controls that reduce watercraft-related CO exposures and prevent injuries and drowning related to CO