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The word "synthetic" in the lube industry hase traditionaly been synonymous with PAO, poly-alpha-olefins, which are made from small molecules. The first commercial process for making PAO was pioneered by Gulf Oil in 1951.
Since then, the demand for PAO has grown and some base oil manufactures began using higher V.I. feedstocks to make mineral oils with V.I.'s that matched the PAO's. These new Group III oils were not manufactured from small molecules like traditional synthetics but they bridged the performance gap at a lower cost. Some lubricant manufactures began replacing PAO's with Group III base oils in their "synthetic" engine oils. This created a controversy in the lubricants industry because some believed that PAO's were the only true synthetics.
The National Advertising Department of the Better Business Bureau ruled that Group III base oils can be considered "synthetic" because modern oils made using hydroisomerization technology have most of the same performance features of the early synthetics.
