In the past, propellants made of CFCs were used, but they were banned because they are harmful to the ozone layer. Prescription CFC inhalers will no longer be available after 2008. (Over-the-counter epinephrine inhalers will remain on the market until the end of 2010.)
HFA inhalers are considered to be safe for the environment. Many people with asthma do not find them to be as effective as their CFC counterparts, though, and/or they have side effects, including allergic reactions to some of the components. They are also much more expensive than CFC inhalers.
Currently, there are only three albuterol HFA rescue inhalers, but most of the common brands of inhaled steroids, such as Flovent and Pulmicort, along with the combination inhalers, such as Advair and Symbicort, have HFA versions. There is no HFA version of the over-the-counter epinephrine inhalers, such as Primatene Mist, however.
