Terminal blending of mid-grade gasoline (using a premium and regular mix) is common practice in the industry. We interpret that terminals engaging in this practice are not considered refiners under the regulations based on the comment "that the EPA believes that multigrade mixing of RFG will result in gasoline that meets all reformulated standards." (Response to comments, fungibility section). We request clarification.
Parties who only mix different grades of certified reformulated gasoline will not be considered refiners or blenders under the reformulated gasoline regulations. Similarly, parties who mix different grades of conventional gasoline which were produced in compliance with the anti-dumping regulations will not be considered refiners under the regulations. (7/1/94)
This question and answer was posted at List of Reformulated Gasoline and Anti-Dumping Questions and Answers: July 1, 1994 through November 10, 1997 (pdf)