"Dry ice bombs" use frozen carbon dioxide trapped in a sealed vessel to generate an explosion. Though dry ice bombs are highly dangerous and illegal in many parts of the country, some people make them for recreational purposes. The unpredictable nature of dry ice bombs makes injuries common, during both construction and deployment.
How They Work
As frozen carbon dioxide warms up, it sublimates into its gaseous state, expanding many times in volume. When the dry ice is in a sealed container, the pressure of the gas builds until the container ruptures. Dry ice bombs are extremely dangerous to anyone who comes in contact with them, including the people building them, because it is impossible to predict when the container will fail. Depending on many factors -- including air temperature, the container's strength and the size and shape of the dry ice pieces -- a dry ice bomb could detonate seconds after sealing or 30 hours later.
Shrapnel
The most serious injuries inflicted by dry ice bombs come from shrapnel. Glass and metal containers shatter into fragments on detonation, often causing lacerations to the face, arms, throat and chest, as well as eye trauma, including corneal and scleral lacerations, traumatic cataracts and retinal detachment. Plastic soft drink bottles are not as dense as glass or metal, but they are constructed to withstand higher pressures, resulting in a higher-energy explosion. If the plastic fragments lodge in flesh, they are difficult to detect with X-rays.
Pressure Effects
In addition to the shrapnel, an exploding dry ice bomb produces a pressure wave as the rapidly expanding gas displaces the air around the blast. This shock wave is extremely loud -- around 140 decibels -- and can cause hearing loss. There have been reports of collapsed lungs in people close to a bomb and lacerations from windows breaking due to the pressure differential.
Temperature Effects
Since dry ice is minus-109 degrees Fahrenheit (minus-79 Celsius), it can cause frostbite when it comes in contact with skin. Two seconds of contact is all that is necessary for first-degree frostbite to occur, freezing and killing cells.
Inhalation Hazard
Gaseous carbon dioxide is 1.5 times heavier than air, and the volumes of gas generated from dry ice can rapidly fill a poorly ventilated area. Concentrated carbon dioxide will cause drowsiness in smaller quantities and increased blood pressure, nausea, dizziness, headache and even loss of consciousness in higher concentrations.
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