FRANKFURT (Reuters) -- When engineers at Mercedes-Benz tasked with field-testing a new refrigerant watched it ignite in a ball of fire before their eyes, it took a while for the significance of their discovery to sink in.
The discovery suggested the new product posed a risk to car passengers. It has set off a battle between Daimler and U.S. conglomerate Honeywell, replete with mudslinging, conspiracy theories and spin-doctoring.
At stake is not just a lucrative business for Honeywell and its partner DuPont Co., who have invested hundreds of millions of dollars to develop, market and produce the coolant known as HFO-1234yf. Their refrigerant also happens to be the only product of its kind that meets new EU climate guidelines.
Because of concerns about greenhouse gases, EU legislators in Brussels have ordered the phasing out of the long-time industry standard, R134a, from January.
By 2017, every single air-conditioned car that rolls off assembly lines for sale in Europe -- roughly 14 million vehicles a year -- could be filled with about $70 worth of HFO-1234yf.
Daimler engineers tested HFO-1234yf in early August. Simulating a leak in the air-conditioning line of a Mercedes B class, they had released a fine mixture of refrigerant and A/C compressor oil, which sprayed across the car's turbo-charged 1.6-liter engine.
The substance caught fire as soon as it hit the hot surface, releasing a toxic, corrosive gas as it burned. The car's windshield turned milky white as lethal hydrogen fluoride began eating its way into the glass.
'Frozen in shock'
"We were frozen in shock, I am not going to deny it. We needed a day to comprehend what we had just seen," said Stefan Geyer, a senior Daimler engineer who ran the tests.
Air-conditioning refrigerants are not the stuff of controversy. Traditionally, they have been made of relatively innocuous chemicals that change from liquid to vapor and back again, transferring heat and cooling the surrounding air in the process.
The Daimler test has sent the industry, and Brussels, scrambling to figure out whether years of tests that showed the new product to be perfectly safe could have been flawed.
If it does pose a danger, they must reconsider plans to introduce the refrigerant across Europe's entire fleet -- and act fast.
"The industry obviously takes very seriously the new findings, which show the refrigerant can be flammable under certain extreme conditions," said Cara McLaughlin, a spokeswoman for Europe's auto industry association ACEA.
After confirming their August results in subsequent tests, Daimler notified the authorities in late September that it wanted to recall all 1,300 cars worldwide that already use the new refrigerant.