Under § 80.522, used motor oil, or used motor oil blended into diesel fuel, may only be used in the fuel system of model 2007 or later diesel motor vehicles if the vehicle or engine manufacturer has received a Certificate of Conformity under 40 CFR Part 86, that certification is explicitly based on emissions data, and the motor oil is added at a rate consistent with the Certificate of Conformity. Under § 80.525, kerosene that a kerosene blender adds (or intends to add) to 15 ppm sulfur diesel must meet the 15 ppm sulfur content standard, as indicated by product transfer documents or test results.

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)