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
Shale gas in the United States a Haynesville Shale gas well. Haynesville shale wells have also been drilled in northeast Texas, where it is also known as the Bossier Shale. From 2008 through 2010 Encana accumulated a "large land position" (250,000 net acres) at an "average $150/acre" in the Collingwood Utica shale gas play in Michigan's Middle Ordovician Collingwood formation. Natural gas is produced from the Collingwood shale and the overlying Utica shale. The Michigan public land auction took place in early May 2010 in one of "America's most promising oil and gas plays". The Devonian-Mississippian New Albany Shale produces gas in the southeast Illinois Basin