Difluoroethane is an extremely flammable gas, which decomposes rapidly on heating or burning, producing toxic and irritating fumes, including hydrogen fluoride and carbon monoxide.
In a DuPont study, rats were exposed to up to 25,000 ppm (67,485 mg/m) for six hours daily, five days a week for two years. This has become the no-observed-adverse-effect level for this substance. Prolonged exposure to 1,1-difluoroethane has been linked in humans to the development of coronary disease and angina. Repeated or sufficiently high levels of exposure, particularly purposeful inhalation, can precipitate fatal cardiac arrhythmia.