In 1945, we added a mobile carbon dioxide fire extinguisher to our power plant safety equipment.
The extinguisher contained 750 pounds of carbon dioxide that created a smothering effect at very low temperature. When the container was opened, the carbon dioxide expanded to form a gas in the atmosphere. Because the gas was heavier than oxygen, it created a "blanket" around the burning fuel and displaced the oxygen surrounding the fuel to extinguish a fire.
Carbon dioxide fire extinguishers were invented by the Walter Kidde Co. in 1924 and are still used today.