Ethylene glycol antifreeze is the most common antifreeze used in automotive applications worldwide. Consisting of a mixture of ethylene glycol and water, the ethylene glycol antifreeze not only resists freezing, it also resists overheating when used in warm climates. The ethylene glycol cannot be used on its own due to the inability of cooling without water present. The higher the percentage of ethylene glycol in the mixture, the lower the freeze point; however, a 50/50 mixture of ethylene glycol and water provides the best all-around mixture of ethylene glycol antifreeze as recommended by most automobile manufacturers. The mixture is a very dangerous chemical if ingested, and it can cause blindness and death even in small amounts.
Commonly used in liquid-cooled automotive and industrial combustion engines, ethylene glycol is also used in most common heating and cooling systems in houses and commercial buildings. The ethylene glycol antifreeze used in automotive applications should not be used in the heating and cooling systems of buildings, however, due to the containment of silicates that are mixed into the automotive antifreeze. The silicates are added to the ethylene glycol antifreeze mixture to combat corrosion in aluminum engine components. It is also imperative to avoid using city tap water in any ethylene glycol antifreeze mixture since many city water supplies are treated with chlorine, which is a known corrosive.
It is very important to keep all opened containers of ethylene glycol antifreeze tightly closed because the chemical is very dangerous to humans and animals. This danger is amplified due to the sweet smell and taste of the thick, syrupy mixture. Animals are commonly drawn to the spilled liquid because of the smell and taste, while the colorful green appearance can tempt young children into believing it is some form of tasty treat. The ingestion of the chemical can lead to permanent blindness and even death if enough of the substance has been ingested.
The toxic makeup of ethylene glycol antifreeze mandates that the disposal of used antifreeze be treated as a hazardous chemical. A small amount of the green fluid can seep into and poison the groundwater supply for a great number of homes. Many auto supply stores offer a service that will collect used or unwanted ethylene glycol antifreeze, provided it is in a properly sealed container. This used antifreeze is beginning to be recycled in many locations, providing a more beneficial option than simply disposing of the dangerous chemicals.