What were CFCS originally thought to be safe and useful and why were they determined to be on safe?

Chlorofluorocarbons (CFCs) were originally deemed safe and useful due to their stability, non-flammability, and effectiveness as refrigerants, propellants, and solvents. However, they were later found to be harmful because they released chlorine atoms in the stratosphere, which contributed to the depletion of the ozone layer. This discovery raised significant environmental concerns, leading to international agreements like the Montreal Protocol to phase out their use. The detrimental effects on human health and ecosystems underscored the need for safer alternatives.