Suicide by Gaseous Displacement of Atmospheric Oxygen With Carbon Dioxide From Dry Ice Sublimation

Deaths from gaseous substances can occur from exposure to toxic gases or from accumulation of nontoxic gases that displace oxygen. We present a 38-year-old man with no known medical history, who was found deceased in a small bathroom with blankets and towels shoved under the door from the inside.At autopsy, the decedent was found to be in a moderate state of decomposition. There was mild pulmonary congestion, with no other significant findings. Standard postmortem toxicology on femoral blood was noncontributory.A search of the decedent's cell phone revealed statements and internet searches regarding carbon dioxide (CO 2 ) and asphyxia using dry ice. A journal entry also outlined a suicide plan using large amounts of dry ice, which was enacted by placing a laundry basket of dry ice into a bathtub containing water. Based on the investigation, the cause of death was determined to be asphyxia from displacement of oxygen with CO 2 .Dry ice sublimates into gaseous CO 2 , which quickly accumulates, with concentrations of 10% or more, rapidly becoming life-threatening. There are no pathognomonic autopsy findings seen in CO 2 -related asphyxia. In these circumstances, scene investigation is the most important factor in determining cause of death.