After over a year of stalemate, the European Commission appears to have finally run out of patience with carmaker Daimler over its defiant refusal to use the HFO refrigerant R1234yf in its new cars.

EC industry minister Antonio Tajani recently announced that the Commission would be taking legal action against the carmaker. Or rather, as it works in the ways of Brussels, the Commission will be taking legal action against the German authorities. These infringement actions are usually a fine against the member state — at worst a substantial fine levied daily until the regulation is complied with, with the expectation that the penalty will be passed down to the disobedient company.

But the evidence provided by the EC makes it clear that they hold the German authorities and Daimler equally to blame.

The charge is not complying with the Mobile Air Conditioning Directive by continuing to use the now-banned refrigerant R134a in new-model cars. Daimler still maintains that R1234yf is flammable in certain circumstances where R134a is not, despite the vast majority of expert sources disputing its evidence. As will be well-known by readers, the use of R1234yf is accepted by U.S. carmakers, particularly because its use entitles carmakers to tax credits, based on its low GWP.

In a move that surprised some, the Commission has also censured the governments of the U.K., Luxemburg and Belgium for allowing Daimler's new Mercedes-brand cars to continue to be registered for road use with the noncompliant R134a, by extending old vehicle approvals.

This "turning a blind eye" to the strictures of the Directive has earned the errant three companies what is known as a "pilot letter" — effectively a warning that infringement measures will follow if they don't either provide substantive evidence to justify their stance or change their ways.

The wheels of European politics grind slowly, and many observers were starting to think that Daimler would somehow manage to string out the dispute over R1234yf long enough to simply switch to its stated preferential carbon dioxidere frigerant — even though that could be another two years away.

Instead, the Commission has finally made its decision, following a thorough review of all the evidence before it, together with all Daimler's counterarguments.

The Commission says it "has tried, during the last months, to find with the German authorities reasonable ways to correct the situation of nonconformity. It has decided now that these efforts did not achieve the intended results, and that it is now time to act."

The supporting documents issued along with the charges make interesting reading, detailing as it does the turbulent recent history of the MAC Directive and making public how Daimler has sought to avoid meeting the Directive's terms.

The Commission makes clear that while it gave carmakers a year's moratorium on its original MAC Directive deadline following concerns about low availability of R1234yf, there is no longer any reason to fail to comply with the law.

Also in its documentation, the EC notes that Daimler started raising concerns about R1234yf in September 2012, but emphasizes that at the time the carmaker only asked for six months' grace. Readers will note that that self-imposed deadline ran out almost a year ago.

The Commission also notes that in February 2013, the German authorities called on that particular vehicle manufacturer to re-establish conformity as soon as possible. However by May, the German motor authority told the EC it had granted permission to keep using R134a.

It is now clear that was the last straw for the Commission, which started investigations in June, ahead of issuing the pilot "preinfringement" proceedings against the German authorities. In terms about as strict as Brussels policymakers can muster, the Commission states its current position as follows:

"The Commission is acting to ensure the enforcement of the MAC Directive by Germany, by requesting that the German authorities fully apply this Directive to vehicles produced by one German manufacturer … Vehicles that are not in conformity with EU law were placed on the EU market by a German manufacturer. However, the German approval authorities opted not to act and did not impose adequate remedial measures on the concerned manufacturer."

On top of that, the Commission suggests that between Daimler and the German authorities, there was collaboration to ensure extensions of the "type-approval" — effectively reclassified — so that cars could continue to use R134a.

"The Commission considers that there are indications that the extensions were requested with the sole purpose of circumventing the application of the MAC Directive, thus depriving it of its intended effects," the EC wrote.

Germany has also offered to pay compensation for its carmaker's transgressions, by way of a payment to cover the climate impact. The EC makes clear, in almost withering fashion that this won't wash: "This proposal was inadequate to respond to the situation for different reasons, related to the lack of legal basis, the scope and the calculation method."

The Commission maintains it is doing this so that the climate objectives of the Directive are fulfilled and that the law is uniformly applied throughout the EU's internal market.

Under EU infringement procedures, Germany has two months to respond.

In its documentation, the Commission stresses that it is technology neutral, but the fact is that R1234yf remains the only refrigerant that is under the MAC Directive's 150 GWP limit. Therefore, while the likes of carbon dioxide and the HFO blend R445 remain under development, the Commission requires every carmaker to use R1234yf.

Of course, it should be remembered that Daimler still clings to its reservations about the safety of R1234yf, refuting the suggestions that simple design modifications will mitigate any risks. While the EU's own scientific body the Joint Research Centre is in the midst of compiling a technical review of the safety findings, this legal action makes plain that the Commission has decided it doesn't accept Daimler's position.

The next question is: What will Daimler — and Germany — do in response to the charges?