Freon is an odorless gas; it does not smell like anything. Freon is a popular refrigerant because it is non-toxic and non-flammable. Although it dates back to 1928, Freon and its related gases are still the safest refrigerants on the market. It is also an effective aerosol propellant, but is no longer used for this purpose.
Freon is a halocarbon chemical, with both chlorine and fluorine-based chemicals, sold under the trade name Freon. While it is no longer used in aerosol products due to the detrimental effect it has on the ozone layer and as a greenhouse gas, Freon is still used as a refrigerant. This is because alternate refrigerants cannot duplicate Freon's non-toxic, non-corrosive and non-flammable qualities.
Although Freon is non-toxic, large quantities of Freon in an enclosed space can cause death by asphyxiation. This is true of any gas other than oxygen, regardless of toxicity. Alternate refrigerants include ammonia, sulfur dioxide and methyl chloride, all of which are toxic. Refrigeration systems utilizing these chemicals pose a serious hazard to the people around them. In the event of a leak, toxic gases seep into the room where the refrigerator or air conditioner is located. These gases are toxic at far lower quantities than the amount of Freon needed to suffocate a human.