Dichlorodifluoromethane (Freon-12) is a synthetic refrigerant used in air conditioning. It can enter water through industrial discharge or improper disposal and depletes the ozone layer.

Dichlorodifluoromethane, also known as Freon-12, is a synthetic chlorofluorocarbon (CFC) once widely used in refrigeration and aerosol products. Its production was phased out globally under the Montreal Protocol due to its ozone-depleting properties. This persistent chemical can contaminate water sources through industrial discharge or improper disposal of old appliances. Environmental agencies typically detect its presence using gas chromatography techniques. While its use has declined, its long-lasting nature means it may still be found in some water supplies.