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
History of the petroleum industry in Canada (natural gas) stacks. One chemical result of burning hydrogen sulphide emissions was sulfur dioxide, another toxic gas. Since hydrogen sulphide is heavier than air, it settled to the ground, dispersed enough to be less than lethal. Hydrogen sulphide was always in the air in small concentrations. Turner Valley had a rotten egg odour on most days. As Alberta became an ever-larger oil producer after the Leduc discovery, the Conservation Board acted to prevent any repetition of the natural gas waste so common in Turner Valley. The board developed a broad conservation policy for natural gas. It prohibited producing natural gas from an