50 years ago scientists found that Chlorofluorocarbons or CFC chemicals in widespread use in refrigeration, air conditioning , and hair spray were beginning to damage the ozone layer in the Earth’s stratosphere which blocks harmful Solar UVB radiation from reaching the surface. The world wide response was the Montreal Protocol banning these chemicals from being released into the atmosphere. It saved millions of humans from dying of skin cancer. Satellite ashes are a new threat to the protective ozone layer.