We've come a long way since the turn of the 20th century, when your refrigerator could prove fatal. In those days, toxic gases (specifically, ammonia, methyl chloride and sulphur dioxide) were used as refrigerants.

Its replacement - CFCs - unfortunately although they serve well as refrigerants, CFCs are considered by the EA to be an environmental hazard. Safe to use in most applications and inert in the lower atmosphere, they undergo significant reaction in the upper atmosphere or stratosphere. There, the chlorine released by CFCs destroys the ozone at the rate of 100,000 molecules of ozone per chlorine atom.

Proceed through this section of the EVC to learn some best practices related to refrigeration units and CFCs.