Propane weighs 4.24 pounds per gallon of gas and at -50 degrees Fahrenheit it is a liquid with a boiling point of -44 degrees Fahrenheit. This means that propane is cold enough to freeze human skin and the tissue underneath skin, causing very severe injuries.
Propane sinks, because it is heavier than air. It is a liquefied petroleum gas produced from both oil and gas wells. Refineries use raw crude oil or raw natural gas to make propane. They then store the propane as a liquid under high pressure, and it becomes a gas when utilized. Propane is made up of three carbon molecules and eight hydrogen molecules.