Carbon monoxide poisonings resulting from open air exposures to operating motorboats--Lake Havasu City, Arizona, 2003.

During February 1997-August 2002, two fatal and six nonfatal cases of carbon monoxide (CO) poisoning occurred in vacationers who were wading in or boating near the Bridgewater Channel of Lake Havasu (Lake Havasu City [LHC], Arizona). The vacationers were near operating motorboats, primarily in the channel area, where large numbers of boaters congregate during holiday weekends. One person had a carboxyhemoglobin (%COHb) level of 40% on autopsy. To evaluate CO exposure among municipal employees working in the channel, CDC and the Havasu Regional Medical Center Emergency Department (HRMCED) conducted an initial investigation during Labor Day weekend 2002 (August 31-September 1). CO concentrations in channel air exceeded all short-term exposure criteria; four of 12 patients reporting to HRMCED because of boating-related activities had %COHb levels of >9%. In May 2003, LHC requested assistance from CDC, the Mohave County Department of Public Health (MCDPH), the Arizona Department of Health Services (ADHS), and a private consulting firm to assess CO exposures in the channel during Memorial Day weekend 2003 (May 23-26). Follow-up environmental surveys were conducted during June-September 2003. This report summarizes the findings of these surveys, which documented excessive CO exposure and confirmed the health risk among vacationers and employees working in the channel near crowded motorboat gatherings. Community leaders and safety officials should 1) be aware that employees and vacationers in close proximity to operating motorboats can be exposed to potentially lethal levels of CO, 2) evaluate exposures, and 3) take steps to prevent poisonings.