Trends in suicide by carbon monoxide inhalation in King County, Washington: 1996-2009.

Carbon monoxide (CO) inhalation is one of the leading methods of suicide in the United States. A sharp increase in suicide by inhaling the CO produced from burning charcoal has been reported in parts of Asia; however, the incidence of this method has not been determined in a U.S. population. Thus, we determined trends of CO suicide in the ethnically diverse population of King County, Washington, U.S.A. During the period 1996-2009, we identified 158 cases of suicide by CO poisoning, with 125 because of automotive exhaust, 26 because of charcoal burning, and seven from other CO sources. While historical U.S. data indicate >99% of CO suicides in the United States occurring by automobile exhaust inhalation, in the most recent years analyzed, c. 40% of CO-related suicides in King County, Washington, were because of charcoal burning, indicating a possible shift in suicide trends that warrants further scrutiny in additional populations.