a) Transmix would merely be designated as such and would not be tracked for EPA purposes unless (and until) it is redesignated for fuel use.
b) It would not be treated any differently. However, transmix processors who are also refiners are held to different standards for the fuel that they produce from transmix.
c) No, there is no difference if it is sold to another, or the original, refiner.
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)