Areas not required to use RFG are subject to the conventional gasoline and federal volatility regulations. States may not set ASTM performance specifications for characteristics or components that are controlled or prohibited by these federal regulations, subject to approval as a SIP revision. For example, state RVP limits in both conventional and RFG areas are preempted unless they are approved as a SIP revision.(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)