Regular readers of my column will recall dispatches on the saga of automotive giant Daimler and its questionable relationship with European refrigerant law, in the shape of the EU Mobile Air Conditioning (MAC) Directive.

As of Jan. 1, 2017, all new cars are required to be fitted with a refrigerant with a Global Warming Potential (GWP) under 150, and now Daimler is back blinking in the headlights. The carmaker has apparently been censured by its own national motor transport authority, the KBA, which last week demanded a recall of some 134,000 of Daimler's models installed with "noncompliant refrigerant."

The recall covers models installed with the refrigerant R134a, supposedly outlawed by the MAC Directive, but which Daimler had been using

I always relish the opportunity to write about Daimler, not least because it allows me to use emotive phrases like "willful disregard of the law" and "flouting of regulations" without fear or favor. But at the same time, the Daimler saga speaks much of the current attitude toward European environmental regulations — and this one was designed to be a flagship with regard to reducing global warming in some powerful quarters.

Because, let's remember, a full four years after the MAC Directive came into force, the German car giant maker of well-known brands ranging from Mercedes to Smart cars is still unpunished for ignoring the Directive's terms for a good chunk of the law's existence.

For those who may have forgotten Daimler's story, here's a whistle-stop summary: The MAC Directive requires cars to use air conditioning containing refrigerant with a GWP under 150. New model types came into scope in 2013, followed by all new cars on Jan. 1, 2017.

Currently, only one refrigerant on the market is able to comply with these terms, namely the HFO R1234yf (which boasts a GWP of "less than 1"). When R1234yf first came out, Daimler and a handful of other carmakers claimed the refrigerant could ignite in the event of a head-on collision. Thus, they refused to use it, instead continuing installation of the previous universally-used R134a (which has a GWP of 3,200).

Over the ensuing years, the automotive industry's scientists, and then the EU's own independent science arm itself, debunked this flammability theory describing the risks as no greater than those posed by other substances in cars, not least gasoline and the vast majority of carmakers duly installed R1234yf in their vehicles.

But Daimler chose to reject the findings of these tests and maintained its view that R1234yf was unsafe. Its response was to keep installing R134a while it sought to develop a CO2-based air conditioning refrigerant. But in October 2015, Daimler announced that it would now comply with the requirement to install R1234yf to comply with this January's rules applying to all new cars, until such time as it could install CO2 in all its models.

CO2 is a refrigerant that the manufacturer has been extensively testing for its Mercedes range, and it will be available this year on S Class and E Class models, the carmaker says. Volkswagen is believed to be readying its Audi A8 model to follow suit with CO2.

Daimler acceded to the installation or R1234yf in tandem with several adjustments to the engine and cooling systems, to eliminate its concerns about the refrigerant being ignited including a system that sprays cooling argon gas onto the cooling system in case of collision.

Many commentators believe this move toward compliance was prompted less by a sudden attack of conscience than by a response to the huge criticism being leveled at fellow carmaker Volkswagen for its falsifying of exhaust emission data. Daimler, many felt, acted to show that German carmakers did not automatically assume they were somehow "above the law."

Quite reasonably, the ongoing stance from Daimler has it in for a good deal of criticism, particularly given that use of R134a has until now been considerably cheaper than the alternative HFO (although this is set to change, as the squeeze on demand on higher-GWP refrigerants continues because of reducing HFC quotas, as I wrote last month).

Not surprisingly, there were calls from the refrigerant industry and others for the European Commission to make an example of Daimler and to "throw the book at it" for its consistent evasion of the MAC Directive. Eventually the Commission did act, charging Germany in December 2015 to appear before its Court of Justice for infringing the MAC Directive.

That case, proving just how slowly the wheels of European commercial justice turn, has still not yet been heard in court.

But this latest development looks like Germany itself is taking action its federal motor authority has issued a recall of all the Daimler-built cars that were fitted with R134a, at the time when they were supposed to be fitted with R1234yf. Is this a reasserting of German environmental leadership or a bid by the country to reduce its inevitable fines for infringing the MAC Directive?

Whatever the motive, the recall inevitably proves both costly and burdensome to Daimler, given that it is estimated to affect some 134,000 Mercedes vehicles, taking in everything from family A Class models to luxury S Class. The requirement to replace all the R134a with R134yf, together with the adjustments to the cooling system and the argon gas system, is reported by German media to be set to cost Daimler anything up to €100 million.

Naturally, the cooling industry in Europe is asking a number of questions: If Daimler complies, will that draw a line on its part in the saga? What effect will the recall by the German motor authority have on Germany's ongoing infringement proceedings? Clearly, it will provide some mitigation, but many hope that there will still be severe fines. And if these are levied against Germany, surely the national authorities will have to penalize Daimler in turn for getting it into such a situation?

One thing is certain: There are many in the cooling industry and in Brussels who want to see Daimler appropriately punished for ignoring the flagship refrigerant directive. For what is the point of a European directive if one company is allowed to continue to flout it?

One more thing: This is all supposing that Daimler agrees to the recall it still has the right to challenge the directive in court. This saga could still run for many months to come.