Inert gas asphyxiation lacks oxygen and consists of an asphyxiant gas (one or more of argon, nitrogen or carbon dioxide), causing the animals to lose consciousness. Argon and nitrogen are important components of a gassing process which seem to cause no pain, and for this reason many consider some types of controlled atmosphere killing more humane than other methods of killing. However, "stunning" is often done using carbon dioxide. If carbon dioxide is used, controlled atmosphere killing is not the same as inert gas asphyxia, because carbon dioxide at high concentrations (above 5%) is not biologically inert, but rather is toxic and also
Natural gas in the United States price of natural gas has been relatively cheap on the North American market, especially compared to oil. Electricity from oil-powered generators in the US declined 81 percent from 2005 to 2014. The states which use the most natural gas for electricity production are, in descending order, Texas, Florida, California, and New York. Liquefied petroleum gas includes the butane and propane natural gas liquids removed in gas processing. They are sold for home heating, cooking, and increasingly for motor fuel. The industry segment is represented by the National Propane Gas Association. Natural gas, in the forms of compressed natural gas, liquified