Federal health officials have alerted asthma patients that the only asthma inhaler currently sold over the counter in the U.S. will be banned next year due to concern that they produce carbon gases that deplete the Earth's atmosphere.

The Food and Drug Administration announced on Thursday that chlorofluorocarbons (CFCs) in metered-dose asthma inhalers that contain the drug epinephrine will no longer be manufactured or sold after Dec. 31, 2011 as part of an international initiative to ban CFCs, which have been proven to diminish the planet's ozone layer. Under the Montreal Protocol on Substances that Deplete the Ozone, various countries agreed to phase out substances that harm the ozone layer, including CFCs, after a certain date.

Primatene Mist, which is manufactured by Armstrong Pharmaceuticals, is currently the only inhaler that will be affected. Primatene Mist is used to temporarily alleviate the symptoms of mild asthma, and is the only FDA-approved inhaler sold over the counter without a prescription, the FDA said in a statement.

The product uses CFCs to propel the medicine out of the inhaler so it can be absorbed into a users' lungs.

If you rely on an over-the-counter inhaler to relieve your asthma symptoms, it is important that you contact a health care professional to talk about switching to a different medicine to treat your asthma, said Dr. Badrul Chowdhury, director of the Division of Pulmonary, Allergy and Rheumatology Products in the FDA's Center for Drug Evaluation and Research.

Individuals who do not have a physician that can write them a prescription for a new inhaler should visit a federally qualified health center, local clinic or community center to meet with a health care professional.

The FDA finalized the phase-out date for inhalers containing CFCs in November 2008 and subsequently notified the public. The agency reports that several manufacturers have replaced CFCs with hydrofluoroalkane (HFA), an environmentally-friendly propellant. However, as of now there is no HFA version of epinephrine inhalers available.

Two other prescription inhalers -- Boehringer Ingelheim's Combivent Inhalation Aerosol and Graceway Pharmaceuticals' Maxair Autohaler -- are scheduled to be phased out by the end of 2013.

CFCs are nontoxic chemicals containing atoms of carbon, chlorine and fluorine that were commonly used in the production of aerosol sprays, as solvents and as refrigerants. While CFCs are stable in the troposphere, when they move into the Earth's atmosphere they are broken down by strong ultraviolet light, releasing chlorine atoms that then deplete the ozone layer, according to the U.S. Environmental Protection Agency.

Although the U.S. has generally banned CFCs in consumer products, their use has been permited in certain medical products deemed essential by the FDA.