Refrigerant Hazards

R-12 SYSTEMS
The Freon refrigerant used in A/C systems is colorless and odorless both as a gas and a liquid. Since Freon boils (vaporizes) at -21.7°F, it will usually be in a vapor state when being handled in a repair shop. If a portion of the liquid coolant should come in contact with the hands or face, note that its temperature momentarily will be at least -22°F.
Protective goggles should be worn when opening any refrigerant lines. If liquid coolant does touch the eyes, bathe eyes quickly in cold water. Then apply bland disinfectant oil to the eyes. See an eye doctor.
When checking a system for leaks with a torch type leak detector, do not breathe vapors coming from the flame. Do not discharge the refrigerant in the area of the live flame. A poisonous phosphene gas is produced when refrigerant is burned. While a small amount of this gas produced by a leak detector is not harmful unless inhaled directly at the flame, the quantity of refrigerant released into the air when a system is purged can be extremely dangerous if allowed to come in contact with an open flame. When purging a system, ensure that hose is directed to a well ventilated area where no flame is present.
Never allow temperature of refrigerant drums to exceed 125°F. The increase in temperature will cause a corresponding rise in pressure which may cause the safety plug to release or the drum to burst.
If it is necessary to heat a drum of refrigerant when charging a system, the drum should be placed in water that is no hotter than 125°F. never use a torch or other open flame. If possible, a pressure release mechanism should be attached before the drum is heated.

R134a SYSTEMS
Avoid breathing A/C refrigerant and lubricant vapor or mist. Exposure may irritate eyes, nose and/or throat. Wear eye protection when servicing the refrigerant system. Serious eye injury can result from eye contact with refrigerant.
Do not expose refrigerant to open flame. Poisonous gas is created when refrigerant is burned. An electronic type leak detector is recommended.
If accidental system discharge occurs, ventilate work area before resuming service. Large amounts of refrigerant released in a closed work area will displace the oxygen and cause suffocation.
The evaporation rate of R-134a refrigerant at average temperature and altitude is extremely high. As a result, anything that comes in contact with the refrigerant will freeze. Always protect shin or delicate objects from direct contact with refrigerant.
Liquid refrigerant is corrosive to metal surfaces. Follow operating instructions supplied with equipment being used.