The fuel sulfur level of a batch of fuel must conform to the way it is designated. If a pipeline has fuel that is designated as 500 ppm or 15 ppm sulfur, and it does not meet the designated level, then it is noncomplying. It is not a defense to claim the fuel should have been designated otherwise by an upstream party.
Question and Answer was originally posted at Questions and Answers on the Clean Diesel Fuel Rules (PDF)(135 pp, 888 K, EPA420-B-06-010, July 2006, About PDF)