* Honeywell says its new coolant is safe
* EU law bans former industry standard because of global warming impact
* Daimler says the new coolant is dangerous, Germany asks for time
BRUSSELS, March 20 (Reuters) - The European Union's industry boss defied opposition from Germany, insisting he would enforce new rules that ban extremely potent greenhouse gases in car air cooling systems.
Luxury car giant Daimler AG says the alternative less polluting fluid on the market is dangerously flammable and is therefore refusing to use it.
German ministers have written to the Commission asking for a temporary suspension of the new law.
Industry Commissioner Antonio Tajani said he had to listen, but he would begin infringement proceedings against any member state that did not comply.
"I am saying very clearly that the directive is in force and has been since January 1. There is no extension. The directive must be respected throughout the European Union," Tajani told the environment committee of the European Parliament.
"Since there was some information from Germany there was a problem, I am obliged to ask for information, but it's not giving them time. I am not weak."
A separate Commission statement underlined that any car maker using R134a, the former industry standard for air conditioning, would face infringement procedures that can lead to daily fines.
British Liberal Democrat member of the European Parliament Chris Davies has followed the car air conditioning systems debate since it first began 2003. He welcomed Tajani's stance.
"The Commission position is very strong indeed. In fact so strong, it amounts to a declaration of war on Daimler," he said. "New models using the old refrigerant must not be sold."
Daimler is not only at odds with the European Commission, but with U.S. firm Honeywell International Inc., which developed the coolant, adopted as the new industry standard, in partnership with Dupont.
Honeywell says its coolant is highly efficient and safe and has been subject to comprehensive testing.
Named HFO-1234yf, the Honeywell fluid is only four times more potent than CO2 and therefore easily meets the EU requirement that bans air conditioning fluids with a global warming potential exceeding 150 times the impact of CO2.
The old standard R1234a is more than 1,000 times more potent than CO2.
In a Daimler test of HFO-1234yf last year involving a simulated leak, the new coolant burst into flames.
"We feel that the security concerns raised by some car producers should be taken very seriously," an EU diplomat, speaking on condition of anonymity, said.
"Therefore, we feel that it would not serve the desired purpose if we forced car producers to use R1234yf."
The Commission does not prescribe which coolant is used provided that it meets the criteria, but the problem is that any alternative Daimler can develop will take time.