Introduction Most carbon monoxide poisoning is preventable. Tracking of longitudinal trends in carbon monoxide-related mortality is needed to guide public health efforts. This study sought to describe mortality in the United States from carbon monoxide poisoning, examine the epidemiology of unintentional (“accidental”) and intentional exposures, and identify trends in both. Methods The Centers for Disease Control and Prevention’s Wonder databases were utilized to extract online data from National Center for Health Statistics files containing mortality data in the United States from 2015-2021. Extracted were deaths, crude death rates, intent of exposure, and demographics of persons dying from carbon monoxide poisoning, excluding cases related to fires. Also extracted was the number of suicidal deaths of all types. Carbon monoxide deaths related to consumer products were obtained from the Consumer Product Safety Commission. Information on state legislation mandating residential carbon monoxide alarms was obtained from online resources. Results Total carbon monoxide deaths decreased from 1,253 in 2015 to 1,067 in 2021. An increase in accidental poisoning deaths was offset by a larger decrease in intentional deaths, despite an increase in suicides of all types in the country. For the first time in the United States, accidental carbon monoxide deaths (543) outnumbered intentional deaths (524) in 2021. The increase in accidental deaths is consistent with those recently reported from carbon monoxide-emitting consumer products by the Consumer Product Safety Commission. Furthermore, even though over one-half of accidental deaths occurred at home, no evidence of a protective effect of state laws requiring residential carbon monoxide alarms was seen. Conclusions Accidental carbon monoxide poisoning deaths increased from 2015-2021 for the first time in four decades. Exploration of the possibility they are due to consumer products warrants attention and prevention efforts. We were unable to demonstrate the preventive effect of residential carbon monoxide alarm legislation.