Halons are a group of chemical compounds that contain bromine, fluorine, and carbon. They were primarily used in fire extinguishers due to their effectiveness in suppressing flames, especially in areas where traditional water-based extinguishers could cause damage, such as in electrical equipment or aircraft. However, halons are known to deplete the ozone layer, which protects the Earth from harmful ultraviolet radiation. As a result, their production was largely phased out under the Montreal Protocol, an international treaty aimed at reducing substances that harm the ozone layer.