"Detailed discussions with company executives make clear that these are not isolated incidents but instead represent common practice across the industry", the environmental group said.
China is a major producer of the rigid polyurethane foams involved and the EIA calculates that if the illegal use of CFC-11 is pervasive in the 3,500 small- and medium-sized companies that make up the sector, then this would explain the surge.
EIA's report discovered that China's foam insulation production was the main cause behind the increased CFC production.
Traders cited by EIA also said that Chinese companies export the banned CFC agents by mislabelling them as Hydrofluorocarbon (HFC) compounds and other chemical blends.
The foreign ministry told AFP on Monday that China had made "tremendous contributions" to achieving the aims of the Montreal Protocol.
HCFC-141b will also be phased out soon in China. By GCR Staff0 CommentsA report issued today by the Environmental Investigations Agency (EIA) has revealed China as the mystery source of an ozone-destroying gas that has been banned by worldwide protocol since 2010.
Production of this ozone-depleting substance in China has also been confirmed by an investigation led by the New York Times, which also spoke to CFC traders in China, and found several court documents over the last few years where companies have been fined for engaging in these environmentally harmful activities. "It has to result in seizures, it has to result in arrests so that people know there are harsh penalties for the production of CFC-11".
Liu Le, a refrigeration expert in Shandong, noted in a presentation to Chinese officials that the situation has been hard to monitor, as these businesses don't have registrations or names on their factories.
The report is released ahead of the Open-Ended Working Group of the Montreal Protocol meeting in Vienna this week.
Dr Stephen Montzka from the US National Oceanic and Atmospheric Administration (Noaa) told BBC News: "The pervasiveness of the use of CFC-11 that seems apparent in China based on their survey is quite awesome, although it is hard for me to assess the accuracy of the emission estimate they make to know if it is indeed likely that this activity can explain all or most of what we are observing in the global atmosphere".
He added: "What we've uncovered is a systemic problem, not isolated incidents".
Clare Perry, EIA UK Climate Campaign Leader, said: "This is an environmental crime on a massive scale". Steps need to be taken to ensure enforcement and compliance with all the obligations of the Montreal Protocol, including new controls on HFCs. "How the Montreal Protocol addresses this issue will determine whether it continues to merit its reputation as the world's most effective environmental treaty".
One seller of CFC-11 estimated that 70% of China's domestic sales used the illegal gas.
But there remains some illegal trade in ozone-depleting chemicals, because they are cheaper than substitutes.