The addition of a blendstock to certified RFG would result in the blender becoming a refiner under the RFG regulation. Refiners must establish a baseline, register with EPA and comply with all the testing, certification and other refiner requirements under the regulation. In consequence, a blendstock may not be added to RFG unless that blendstock meets all RFG standards. Any company that does meet the requirements of an RFG refiner, however can produce RFG through blending.
RFG which is changed in this manner could, however, be sold outside the RFG covered areas as conventional gasoline. However, the blender is considered a refiner under the antidumping requirements and thus is responsible for the properties of the blendstock which is added to the finished RFG. Antidumping compliance calculations for blendstocks which are added to finished gasoline are discussed in section IX (D) of the preamble to the final regulations at 59 FR 7806.(7/1/94)
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)