The insurance industry has been blasted for blocking the recovery of highly potent greenhouse gases contained in hundreds of thousands of written-off vehicles sold at auction each year.
About 600,000 cars are sold each year for parts and scrap metal. Each contains about 250 grams of hydrofluorocarbon (HFC) 134a gas in its airconditioning unit, little of which is recovered though a law bans its deliberate release.
Since HFC134a has about 1300 times the global warming impact of carbon dioxide, capturing the gas could save the equivalent of 200,000 tonnes of C02-equivalent in annual emissions.
Advocates of a new gas recovery technology say the two main auction firms - Manheim and Pickles - would allow cars to be de-gassed within minutes before sale but only the owners - typically insurers - can give the all clear.
"If the insurance companies said they wanted to do it, we'd work with them to facilitate it," said Mathew McAuley, Manheim communications manager.
Grabbing the gas before a sale is vital since buyers of the wrecks number in their thousands, making enforcement of the 1989 act banning release of HFCs and ozone-depleting refrigerants almost impossible, said Barry Isenberg, a consultant to the dismantling industry.
"It's a win for the environment; it costs nothing for insurance companies, or the auction houses," said Mr Isenberg, who was once dubbed by US media as "the messiah of the auto recycling industry".
Greens leader Christine Milne has also written to the Insurance Council of Australia and to Amanda Rishworth, the parliamentary secretary for sustainability and urban water, to urge insurers to give de-gassers access to the cars.
"I'd like to see greater compliance [with the law] by requiring written-off vehicles to be de-gassed prior to auction," Senator Milne said.
Campbell Fuller, spokesman for the Insurance Council, said the gas was "a commodity and forms a significant part of the value of the vehicles being sold".
But an industry official said it was "absolute nonsense" that the gas had any significant value, and that "everybody would be a winner" if insurers gave de-gassers access to the cars since most of the gas would simply end up in the atmosphere without intervention.