Biodiesel is used as a lubricant additive itself. Very slippery stuff. Might need other additives to meet national standards. Lots of home brewers run it neat. It does need careful washing.Yup, the additives are added at the time of tanker loading. Many "brand name" fuels are base stock with a certain detergent/optimiser chem pack added before the tank is filled. Tank Wagons use the "slosh" method of mixing. Will have to walk across the street to the Biodiesel guys and ask what they add.