Dirt Hauler:
Beware! Your supplier that provides clear, "off road" diesel without the federal and state highway use taxes is asking for serious trouble. The statement by the IRS of "tax or dye" means if diesel fuel is sold without the tax it must be dyed.
What would prevent someone from buying clear "off road" diesel and burning it in their highway vehicles? Nothing, but their own honesty. That's why all off road fuel must be dyed. The only exception being jet fuel because the aviation industry was strong enough to stop the requirement ot dye jet fuel claiming it would be unsafe to fly with such dye in the fuel.
I'm 99% certain that your friendly supplier can not legally sell clear diesel without the tax unless the law changed in the last few years. If you purchase it, how will you prove that you did not use the clear "off road" fuel on the road. Since the tax is frequently collected at the "rack", when the trucks are loaded at the refinery, it's very hard to get clear "off road" diesel that does not have the tax paid already.
The Internal Revenue Service Criminal Investigation Division (IRS CID) (those are the guys with the firearms and powers of arrest, search and seizure; the same ones that got Al Capone) have conducted numerous Motor Fuel Excise Tax intestigations throughout the coutnry and Burned many people illegally selling highway fuel as off road fuel. The penalty for this is a huge fine if you're lucky and hard prison time plus the fine if not so lucky. Their purchasing customers frequently get toasted along with them in the form of significant fines.
The IRS CID conducts surveillances on distributors, transporters and eventually customers in order to develop evidence that will hold up in Federal court.
As you probably know, there is little profit in fuel sales per gallon, so if one station in an area is selling fuel for 5 - 10 cents per gallon less than a neighboring station, there is a very good chance that he is cheating. There is just not enough profit in fuel to allow such a price difference.
Those same dealers that sell fuel that much cheaper are either buying non-taxed fuel illegally, or are blending something into the fuel. IRS CID criminal case evidence has shown that the cheating dealer will frequently add used crankcase oil, jet fuel that the military has sold as contaminated fuel (left over fuel in military jets is stored then sold and must be re-refined; it can not be sold as jet fuel legally), and in some cases even toxic waste. Some truck drivers bought this crap that they thought was cheap diesel fuel only to have their $20,000.00 diesel engines fail in literallyjust a few miles.
The risks simply are not worth it. That's why I only purchase name branded diesel and gasoline from established reputable dealers. Engine failures are too costly to do otherwise.
Fortunately I have a local diesel supplier that sells off road dyed diesel fuel.
Sorry Dirt Hauler, I didn't intend to be so preachy.