Chlorofluorocarbons (CFCs) are a family of non-toxic, inert chemical compounds that contain chlorine, fluorine and carbon bound tightly to form inert molecules. They were originally developed in 1930 as a safer alternative to the refrigerants then in use, such as sulfur dioxide and ammonia, which are corrosive and toxic.

Several kinds of CFCs are widely used: CFC 11, CFC 12, CFC 22, and CFC 113. Halons, which are used in firefighting, are also ozone-depleting. CFC compounds are used worldwide in aerosol sprays (a use banned in the U.S. and a few northern European countries in the mid-70s); refrigeration and air conditioning; rigid foam insulation and flexible upholstery foam; and cleaning solvents, especially for washing micro-electronic chips and other electronic components.

Chemical Properties:

Each kind of CFC has a different formulation, as shown below. CFC 11: CCl3F (Trichlorofluoromethane) CFC 12: CCl2F2 (Dichlorodifluoromethane) CFC 22: CHClF2 (Chlorodifluoromethane) CFC 113: C2Cl3F3 (Trichlorotrifluoromethane)

The chemical stability of CFCs allows them to reach the stratosphere, where intense ultraviolet radiation causes them to break apart and release chlorine, which in turn reacts with oxygen, nitrogen and hydrogen oxides in the stratosphere. The result is a reduction in stratospheric ozone, which protects the earth from the sun's ultraviolet rays. Some CFCs are more harmful to stratospheric ozone than others. (Note: "Good ozone" is in the stratosphere and differs from "bad" atmospheric ozone or smog.)

The halons and the most harmful CFCs (11, 12, and 113) are long-lived in the stratosphere, inflicting damage on ozone for decades. Formulations with hydrogen, such as CFC 22, degrade more rapidly than those without hydrogen, and they therefore can be alternatives to the fully-halogenated CFCs. Formulations containing fluorine but not chlorine do not threaten the stratosphere.

Synonyms for chlorofluorocarbon 12 are dichlorodifluoromethane; algofrene type 2; arcton 12; arton 6; carbon dichloride difluoride; CF 12; CF 12(halocarbon) CFC 12; CFC-12; chladone 12; dichlorodifluoromethane (CCL2F2); dichlorodifluoromtheane (DOT French); dichlorodifluoromethane (DOT); diclorodifluorometano (DOT Spanish); difluorodichloromethane; dymel 12; electro-CF 12; eskimon 12; F 12; F 12 (halocarbon); F-12; FC 12; FCC 12; FWK 12; fluorocarbon 12; forane 12; freon 12; freon F-12; freon ® 12; frigen 12; frigen R12; fron 12; gas refrigerante R-12 (DOT Spanish); gaz refrigerant R-12 (DOT French); genetron 12; genetron ® 12; halon 122; halon ® 122; HC 12; isceon 122; isotron 12; khladon 12; ledon 12; methane, dichlorodifluoro-; propellant 12; R 12; R 12 (refrigerant); refrigerant 12; refrigerant gas R-12; refrigerant R 12; SDD 100; and ucon 12.

Identification:

• Chemical Name: Chlorofluorocarbon 12
• Regulatory Name: CFC-12, Dichlorodifluoromethane
• Formula: CC12F2
• DOT Label: Non-flammable Gas
• CAS: 75-71-8
• STCC: 4904516, 4904561
• CHRIS: DCF
• UN Number: 1028

Health Effects:

Though industry favors CFCs because they are non-toxic, CFCs are primarily responsible for depletion of the earth's stratospheric ozone layer, which shields life on earth from harmful ultraviolet radiation.

Known and suspected effects of ozone depletion include increased skin cancer, eye disorders (such as cataracts and retinal damage), suppression of human immune systems, harm to aquatic systems and biological organisms, exacerbation of smog in some urban areas, and degradation of some plastics and paints. Conditions aggravated by exposure to ultra-violet radiation include nutritional deficiencies, infectious diseases and autoimmune disorders.

In addition, CFCs account for approximately 15 percent of the chemicals responsible for the greenhouse effect, which threatens to increase global temperatures and cause sea levels to rise. This would cause more frequent drought, heat waves, polluted water supplies and tropical diseases in northern latitudes.

Exposure Values:

• IDLH: 15,000 ppm (NIOSH, 1997)
• TLV TWA: 1000 ppm (ACGIH, 1999)
• NIOSH REL: TWA 1000 ppm (4950 mg/m3)
• OSHA PEL: TWA 1000 ppm (4950 mg/m3)

Economics:

U.S. manufacturers of chlorofluorocarbons are Allied-Signal Inc, Danville, IL, El Segundo, CA; Du Pont Co, Antioch, CA, Montague, MI; ELF Atochem North America, Inc, Calvert City, KY; Racon, Inc, Wichita, KS; Union Carbide Corp, Somerset, NJ; LaRoche Chemical, Inc, Baton Rauge, LA; and Atochem North America Inc, Philadelphia, PA.

Findings link CFCs to massive ozone depletion over Antarctica and ozone losses over much of the Northern Hemisphere, and threaten similar depletion in the Arctic. CFC manufacturers therefore are being forced to phase out production of CFCs and develop substitutes.

Regulation:

More than 30 nations met in Montreal and signed a treaty agreeing to cut production of CFCs by 50 percent by 1999.

Under Section 313 of the Emergency Planning and Community Right to Know Act of 1986, releases of more than one pound of chlorofluorocarbons into the air, water, and land must be reported annually and entered into the Toxic Release Inventory (TRI).

National Overview of 1998 Toxics Release Inventory

See EPA's Toxic Release Inventory.