Final answer:
Halons or halogenated hydrocarbons (CFCs) used in fire extinguishers are being replaced due to their harmful impact on the ozone layer.
Step-by-step explanation:
Extinguishing agents that are being replaced due to their damaging effects on the earth's ozone layer are A. Halons or halogenated hydrocarbons. Halons, which are chlorofluorocarbons (CFCs), have been primarily used in fire extinguishers. CFCs and similar compounds such as methyl bromide were synthesized for use in refrigerants, aerosol sprays, foaming agents for plastics, and as biocides. Unfortunately, these compounds contribute to ozone depletion when they release chlorine (Cl) or bromine (Br) atoms after being broken down by ultraviolet (UV) radiation in the stratosphere. These atoms catalytically destroy ozone (O3) molecules, which are essential for protecting the Earth from harmful UV radiation. International environmental legislation under the Montreal Protocol has led to a phase-out of CFCs and similar ozone-depleting substances such as halons. As a result, more environmentally benign alternatives like hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) are being used as replacements for the damaging CFCs.