Dry ice is the solid form of carbon dioxide (\(\text{CO}_2\)), a compound that exists as a gas under normal atmospheric conditions. Because of its extremely low temperature and unique phase change properties, ingesting dry ice is profoundly dangerous. Consumption of dry ice, even in small amounts, should never be attempted, as it rapidly leads to severe, life-threatening injuries.
Understanding Dry Ice Composition and State Changes
Dry ice does not melt into a liquid under standard atmospheric pressure; instead, it undergoes a process called sublimation.
The sublimation point of dry ice is an intensely cold \(-78.5^\circ\text{C}\) (\(-109.3^\circ\text{F}\)). As soon as the solid carbon dioxide is exposed to the much warmer environment of the human body, it instantly begins to convert into \(\text{CO}_2\) gas. There is no liquid phase to drink, only the rapid production of cold gas. This unique physical property is the source of the most immediate dangers upon ingestion.
Immediate Physical Hazards of Ingestion
The most immediate danger comes from extreme thermal shock and the resulting cryogenic burn. The \(-78.5^\circ\text{C}\) temperature will instantly freeze moist tissues in the mouth, throat, and esophagus, causing severe frostbite-like injuries. This rapid freezing process destroys cellular structures and can lead to deep tissue necrosis, similar to a severe thermal burn.
A second major physical threat is the rapid expansion of volume within the confined space of the gastrointestinal tract. When solid \(\text{CO}_2\) sublimates into gas, its volume expands by a factor of approximately 760 to 800 times. If a piece of dry ice is swallowed, this massive expansion of gas inside the stomach or intestines creates enormous internal pressure.
This pressure buildup can lead to severe gastric distension, intense pain, and potentially a catastrophic rupture or perforation of the stomach or esophageal lining. The physical force generated by a small piece of dry ice converting to gas is sufficient to cause a life-threatening internal injury that requires immediate surgical intervention.
Systemic and Chemical Risks
Ingestion introduces systemic chemical risks related to carbon dioxide absorption. When the \(\text{CO}_2\) gas produced by sublimation dissolves into bodily fluids, such as saliva or stomach acid, it forms carbonic acid (\(\text{H}_2\text{CO}_3\)). This chemical process lowers the \(\text{pH}\) and results in a chemical burn that further damages the mucosal lining of the digestive tract.
The rapid introduction of large amounts of \(\text{CO}_2\) gas also poses a risk of hypercapnia. If the body absorbs this gas faster than the lungs can expel it, it can trigger a condition known as respiratory acidosis. This imbalance can quickly affect the central nervous system, leading to symptoms like confusion, dizziness, headache, and in severe cases, seizures, coma, or cardiac arrest.
Emergency Response and First Aid
Immediate action is mandatory if dry ice is ingested or if a severe cryogenic burn occurs. Call emergency medical services immediately, such as 911, or contact a local poison control center for guidance. Do not attempt to induce vomiting, as this can cause further corrosive damage to the esophagus and airway.
While waiting for professional medical help, move the affected person to an area with fresh air, particularly if signs of \(\text{CO}_2}\) poisoning, such as rapid breathing or confusion, are present. For external contact, do not rub the affected area, as this can worsen tissue damage. The patient will require specialized medical treatment to address the internal burns, pressure injury, and potential chemical imbalances.