Booming demand for flat-screen televisions could have a greater impact on global warming than the world's largest coal-fired power stations, scientists warn.
A greenhouse gas called nitrogen trifluoride, used to make the TVs, is 17,000 times more potent than carbon dioxide, said Michael Prather, director of the environment institute at the University of California, Irvine.
But no one yet knows how much of it is being released into the atmosphere by industry, a report in Britain's The Guardian said.
Prather's research shows production of the gas, which remains in the atmosphere for 550 years, is "exploding".
It is expected to double by next year, from the current 4,000 tons produced annually.
But unlike other key greenhouse gases — such as carbon dioxide, sulphur hexafluoride (SF6) and perfluorocarbons (PFCs) — emissions of the gas are not restricted under the Kyoto protocol or similar agreements, The Guardian report said.
Prather and his colleague Juno Hsu — writing in the journal Geophysical Research Letters — said this year's production of nitrogen trifluoride is equivalent to 67 million tons of carbon dioxide.
That meant the gas has "a potential greenhouse impact larger than that of the industrialised nations' emissions of PFCs or SF6, or even that of the world's largest coal-fired power plants".
Air Products, which produces the gas for the electronics industry, told New Scientist that very little nitrogen trifluoride is released into the atmosphere.
But Prather raised concerns about companies being careless with the gas, given the lack of a regulatory framework.