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
Phase-out of incandescent light bulbs significant health risks to adults, including pregnant women, or to children. If all electricity was generated by a coal power plant (which produce about half the electricity the U.S. consumes) and fluorescent light bulbs were all recycled with no mercury being lost, nearly 75% less mercury could be released in power plant emissions if incandescent bulbs were replaced by fluorescents, and with significantly less total mercury release even if no recycling occurred. However, a concern is that broken bulbs will introduce the mercury directly into a populated indoor area. Though more recent analysis indicates that the concerns about mercury release