Health hazard evaluation report: HETA-2001-0090, Fun Country Marine Industries Inc., Callville, Nevada.
On December 1, 2000, the National Institute for Occupational Safety and Health (NIOSH) received a request from management officials of Fun Country Marine Industries Inc. to evaluate carbon monoxide (CO) concentrations associated with the operation of houseboats on Lake Mead. On January 23 - 24, 2001, NIOSH investigators visited Lake Mead to investigate CO concentrations on houseboats located at Callville, Nevada. This letter describes our evaluation methods, findings, and conclusions. The Fun Country Marine houseboats evaluated at Callville Marina were designed with a solid hull and did not have any enclosed spaces beneath the back deck. With this type of design the CO levels could not build up in an enclosed space beneath the back deck as seen on previous evaluations. During this evaluation, CO concentrations near the exhaust (measured with the emissions analyzer) would dissipate quickly (within a few minutes) after the generator engines were turned off. However, when gasoline generators were in operation, extremely high CO concentrations (above IDLH levels) were measured near the generator exhaust. High CO concentrations (occasionally measured above IDLH) were also measured around the back deck (near water level), on houseboats that exhaust the generator combustion gases out the back. These hazardous conditions also exist when the engines are in operation on the boats. During this survey, only one of the houseboats exhausted the generator to the side of the boat hull. The area around the exhaust on the side of the boat indicated CO concentrations above the NIOSH IDLH value of 1,200 ppm when measured at the dock and in a cove on the lake. CO concentrations around the back deck (approximately 6-12 inches above the water where individuals could conceivably be swimming) indicated high CO concentrations (896 ppm) while the boat was at the dock, and while stationary in a cove on the lake, CO concentrations were measured above the NIOSH IDLH value. In the cove, high CO concentrations (>1000 ppm) were also measured on the floor of the back deck while the generator was in operation. This investigation documents the potential for CO exposure on houseboats that utilize gasoline generators that exhaust out the back or the side near water level. Individuals swimming or working in the area directly near the exhaust or behind the back deck (with the gasoline generator in operation) could be exposed to extremely high CO concentrations resulting in CO poisoning or death within a short period of time. The area on the back deck of houseboats is also a concern. When the generator or motors are in operation, the area around the back deck of houseboats can be hazardous under certain conditions, particularly when there is little air movement.