It is not a violation of the RFG regulations to commingle two legal RFG products at a retail outlet or wholesale purchaser-consumer facility, or a violation of § 211(f) to commingle two legal conventional gasolines at a retail outlet or wholesale purchaser-consumer facility.
However, this could cause compliance problems with the summertime RFG requirements for RFG, or summertime volatility restrictions for conventional gasoline.(8/29/94)
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)