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Companies in China and India that make the refrigerant hydrochlorofluorocarbon-22 (HCFC-22) may stop capturing and destroying a by-product gas with potent greenhouse effects, now that a profitable carbon credit trading system has ended. Unless the firms are required to destroy the by-product trifluoromethane (HFC-23), an activist group warns, there will be a “climate bomb” of additional releases of this greenhouse gas.

The greenhouse effect of HFC-23 is 11,700 times that of CO 2, according to a conservative estimate by the United Nations. Under the 1997 Kyoto protocol, registered manufacturers in developing countries installed equipment to destroy HFC-23 and earned huge numbers of carbon emission reduction credits. The credits were sold in markets such as the European Union Emissions Trading System. The gas cost very little to destroy, and sale of credits brought billions of dollars to companies in China and India.

The Environmental Investigation Agency (EIA) and other activist groups alleged manipulation of the credit program by HCFC-22 makers in 2010. As a result, carbon markets recently stopped accepting credits for HFC-23 destruction. Now that it’s not profitable to capture the gas, according to EIA, “Many former [credit-earning] Chinese and Indian plants may begin venting rather than destroying HFC-23 in the coming months, if they have not started already.”

Those emissions would add to releases from companies that are not part of the credit program. In the U.S. and Europe, firms such as DuPont, Honeywell, and Arkema that make HCFC-22 have long destroyed their waste HFC-23. Arkema, which runs one of the Chinese plants that had earned carbon credits, says it will nonetheless continue to destroy HFC-23. Navin Fluorine, a major Indian manufacturer that earned carbon credits, has not announced its postcredit plans.

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