It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Some features of ATS will be disabled while you continue to use an ad-blocker.
A CHEMICAL USED IN dry cleaning and fire extinguishers may have been phased out in recent years but NASA said on Wednesday that carbon tetrachloride (CCl4) is still being spewed into the atmosphere from an unknown source.
The world agreed to stop using CCl4 as part of the Montreal Protocol, which aims to phase out the use of gases which damage the Earth's protective layer of ozone.
"Parties to the Montreal Protocol reported zero new CCl4 emissions between 2007-2012," the US space agency said in a statement.
"However, the new research shows worldwide emissions of CCl4 average 39,000 tonnes per year, approximately 30 per cent of peak emissions prior to the international treaty going into effect."
"We are not supposed to be seeing this at all," said Qing Liang, an atmospheric scientist at NASA's Goddard Space Flight Centre. "It is now apparent there are either unidentified industrial leakages, large emissions from contaminated sites, or unknown CCl4 sources."