One Woman Dead, One in Critical Condition from Exposure to Dry Ice Vapors in Car

Coolers of dry ice in the trunk are responsible for the death of one woman and near suffocation of another in Seattle, reports ABC News.

An ice cream salesman had four coolers full of dry ice in the trunk of his car. Dry ice, which is frozen carbon dioxide, is significantly colder than water ice, -109.3 degrees Fahrenheit rather than 32 degrees Fahrenheit, making it ideal for keeping ice cream and other frozen items cold for extended periods of time.

The salesman's wife borrowed his car to drive his mother home on Friday. They never arrived, and a search began hours after they had left. The car was found just blocks away from the salesman's home. The mother, Hildegard Whiting, was dead. The wife barely survived and remains in critical condition.

In normal temperatures, dry ice doesn't melt but turns directly into carbon dioxide gas. (It's called "dry ice" because it skips the liquid phase of matter entirely.) This gas apparently leaked out of the coolers and filled the interior of the car. Unlike carbon monoxide, which is deadly when inhaled, carbon dioxide is harmless in the small quantities that it naturally exists in the atmosphere. Dry ice is commonly used for harmless smoke effects at concerts, shows, and parties. 

But carbon dioxide gas, by itself, is denser than air. That's why the smoke that comes from dry ice sticks to the floor rather than rising up like smoke from a fire. In confined places, such as the interior of a car, carbon dioxide can invisibly displace our natural oxygen-rich atmosphere. With a large amount of dry ice stored in the car's trunk, this appears to be what happened in this case.