What You Need to Know about Metered Dose Inhalers and the HFA Propellant Make an Appointment Patient Education Find a Doctor Download Patient Education The metered dose inhaler (MDI) was developed in the 1950s. The propellant used in MDIs until recently contained CFCs (Chlorofluorocarbons). You may find when you replace your MDI that a different propellant is used in the inhaler. This is an HFA (hydrofluoroalkane) propellant. Download PDF: What You Need to Know about Metered Dose Inhalers and the HFA Propellant Download PDF: What You Need to Know about Metered Dose Inhalers and the HFA Propellant View more information on HFA Propellant National Jewish Health authors free downloadable patient education materials to provide you and your family the information and tools to help manage your disease. They include Understanding Booklets, Med Facts, Test Facts, Medication handouts and more. Search Free Education Materials