39 kilotons a year: Mysterious source of ozone-depleting chemical banned since 2009 baffles NASA

By Agence France-Presse
Thursday, August 21, 2014 5:55 EDT

A chemical used in dry cleaning and fire extinguishers may have been phased out in recent years but NASA said Wednesday that carbon tetrachloride (CCl4) is still being spewed into the atmosphere from an unknown source.

The world agreed to stop using CC14 as part of the Vienna Convention on Protection of the Ozone Layer and its Montreal Protocol, which attained universal ratification in 2009.