Inert gas In food packaging, inert gases are used as a passive preservative, in contrast to active preservatives like sodium benzoate (an antimicrobial) or BHT (an antioxidant). Historical documents may also be stored under an inert gas to avoid degradation. For example, the original documents of the U.S. Constitution is stored under humidified argon. Helium was previously used, but it was less suitable because it diffuses out of the case more quickly than argon. Inert gases are often used in the chemical industry. In a chemical manufacturing plant, reactions can be conducted under inert gas to minimize fire hazards or unwanted reactions.
Phase-out of incandescent light bulbs mercury contamination from CFLs have been raised, but CFLs can be shown to result in less mercury in the environment compared to traditional incandescent bulbs due to the significant reductions in power plant emissions. Thus, use of energy-efficient bulbs can actually reduce the amount of mercury released into the environment. Compact fluorescent lamps start poorly when very cold, and most types cannot be dimmed. A few specialist applications are unsuitable for CFLs. Light emitting diode (LED) lamps are used for both general and special-purpose lighting. Compared to fluorescent bulbs, their advantages are that they contain no mercury, they turn on