A type of chlorofluorocarbon (CFC) whose production or import is banned in industrialized countries has been smuggled into Japan in large volumes from China and other developing countries where its manufacturing is still allowed, customs authorities and industry sources said Sunday.

CFCs are blamed for depleting the ozone layer and causing global warming. The smuggled products are being used as an auto refrigerant for outmoded vehicles, according to the sources.

More than 100,000 bottles of smuggled CFC-12, or dichlorodifluoromethane, have been circulating among Japanese maintenance service providers since last year, prompting authorities to launch investigations, they said.

The customs authorities and auto parts sellers believe several dozen to 1,000 cases containing 30 CFC-12 bottles each have so far been traded in Japan. The authorities said they are investigating several suspected smuggling channels in eastern, central and western Japan.