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 barrels per day in 2014. The US has been the world's leading producer of natural gas liquids since 2010, when US NGL production passed that of Saudi Arabia. Although the United States leads the world in natural gas production, it is only fifth in proved reserves of natural gas, behind Russia, Iran, Qatar, and Turkmenistan. The United States oil and gas industry is often informally divided into "upstream" (exploration and production), "midstream" (transportation and refining), and "downstream" (distribution and marketing). Petroleum and natural gas share a common upstream (exploration and production) sector, but the midstream and downstream sectors are largely