Carbon monoxide intoxication remains a major cause of morbidity and mortality in the United States with an estimate of 50,000 cases annually in emergency departments nationwide (Weaver, N Engl J Med. 2009;360:1217-25). Sources of carbon monoxide most often include car exhaust, malfunctioning heating systems and inhaled smoke. It has been well established that there is a dose-dependent increase in carboxyhemoglobin (COHb) concentration with tobacco use. It is generally accepted that heavy smokers have COHb levels <10% to 15% (Ernst and Zibrak, N Engl J Med. 1998;339:1603-8). The authors report a 48-year-old woman with significant tobacco abuse who presented with COHb levels as high as 24.2% in the face of tobacco use.