EPA has described procedures for pipelines to blend transmix into conventional gasoline and RFG under certain situations. A pipeline that blends transmix into either conventional gasoline or RFG using the procedures described in these answers will not be treated as a refiner, and therefore will not have to be registered as a refiner or to meet the requirements that apply to refiners.
However, if the pipeline fails to comply with the procedures that are specified in the transmix blending answer, EPA will treat them as a refiner and require compliance with the registration and other applicable requirements.(10/3/94)
This question and answer was posted at Consolidated List of Reformulated Gasoline and Anti-Dumping Questions and Answers: July 1, 1994 through November 10, 1997 (PDF)(333 pp, 18.17 MB, EPA420-R-03-009, July 2003, About PDF)