Lethal carbon monoxide generated from small internal combustion engines

Fuel-burning small engines have the potential to emit dangerous and potentially lethal concentrations of carbon monoxide when used in poorly ventilated environments. The North Carolina Office of the Chief Medical Examiner investigated seven cases from 2013 to 2020 involving lethal carbon monoxide from small internal combustion engines. Evaluation of percent carboxyhemoglobin saturation was determined in these case studies as ratios of carboxyhemoglobin to reduced hemoglobin, using HP 8453 and Agilent 8454 UV-Visible Spectrophotometers (Agilent Technologies, Santa Clara, CA, USA). Sources of carbon monoxide included a pressure washer, a propane-powered forklift, an inboard engine boat, a motorcycle, propane and kerosene heaters, and home-use generators. It was demonstrated during a death investigation that the Dräger X-am 2000 electrochemical gas monitor often used by first responders, falsely reacted to acetylene gas, initially misleading investigators to the source of the carbon monoxide. Educating first responders about not only the hazards of these unexpected carbon monoxide sources, but the limitations of their equipment, is a valuable goal of disseminating complete medical examiner case information. The details of these cases will educate first responders, the forensic science community, and public health leaders on potential small engine sources of carbon monoxide in death investigations, responder safety, and the limitations of portable air quality monitoring equipment during death investigation.