Carbon monoxide (CO) poisoning is a pervasive yet preventable threat in the United States, causing significant harm each year. According to the U.S. Centers for Disease Control and Prevention, at least 430 Americans die annually from unintentional CO poisoning, and an estimated 50,000 people seek emergency care due to accidental exposure. These numbers may be conservative, as symptoms — which include headache, dizziness, nausea, vomiting, and confusion — are common and easily misdiagnosed.
These incident rates make CO one of the leading causes of non-drug-related poisoning deaths nationwide, particularly during colder months and in the aftermath of storms, when reliance on fuel-burning appliances and portable generators increases.
CO poisoning also imposes substantial economic burdens on Americans, with one study estimating annual medical costs ranging from $33.6 million to $37.7 million, with additional non-medical costs of $3.7 million to $4.4 million. Another analysis conservatively places the overall societal cost at over $1.3 billion per year, encompassing direct hospital costs, lost earnings, and related expenses.
Recognizing the urgency of this “silent killer,” UL Standards & Engagement has developed the CO Risk Assessment to evaluate each U.S. state’s code and regulatory efforts, health outcomes, and public awareness. The assessment draws on multiple data sources across the last two decades to ensure a comprehensive assessment across public health outcomes, state-level mandates for indoor CO detector presence, and public awareness measures. These three pillars — weighted at 40%, 35%, and 25%, respectively — produce an overall weighted score out of 100 for each state. The weighting approach balances the diverse factors affecting CO safety, ensuring that the assessment reflects each component’s relative impact on public health.