I've posted several times about this, but the notion that there was some sort of lawsuit regarding the use of the term synthetic still persists and is attaining "urban legend" status.
There was not and never has been any suit AT LAW regarding the use of the term "synthetic" for Group III base oil, and no court or ALJ has made a ruling on this matter. Mobil simply filed a complaint with the National Advertising Division of the Better Business Bureau in the US claiming that Castrol was engaging in false advertising by calling Syntec "full synthetic" since it was now being made with Group III base oil. Castrol was able to present enough "evidence" to convince the NAD that Group III base oil could legitimately be called synthetic, so they rulled in Castrol's favor. This ruling has no "legal" standing. It merely means that as far as the NAD is concerned, an oil company is not falsely advertising an oil as "full synthetic" if that oil is made from Group III base oil.
The NAD is merely a self-regulatory arm of the BBB and has no legal standing whatsoever in the U.S. Hence, their ruling in this matter does not make it "legal" to claim that a Group III oil is "synthetic." It merely means that for any entity willing to abide by the NAD's guidelines, a Group III oil can be ADVERTISED under those guidelines as a synthetic.
There was not and never has been any suit AT LAW regarding the use of the term "synthetic" for Group III base oil, and no court or ALJ has made a ruling on this matter. Mobil simply filed a complaint with the National Advertising Division of the Better Business Bureau in the US claiming that Castrol was engaging in false advertising by calling Syntec "full synthetic" since it was now being made with Group III base oil. Castrol was able to present enough "evidence" to convince the NAD that Group III base oil could legitimately be called synthetic, so they rulled in Castrol's favor. This ruling has no "legal" standing. It merely means that as far as the NAD is concerned, an oil company is not falsely advertising an oil as "full synthetic" if that oil is made from Group III base oil.
The NAD is merely a self-regulatory arm of the BBB and has no legal standing whatsoever in the U.S. Hence, their ruling in this matter does not make it "legal" to claim that a Group III oil is "synthetic." It merely means that for any entity willing to abide by the NAD's guidelines, a Group III oil can be ADVERTISED under those guidelines as a synthetic.