After EPA promulgates a federal fuel control or prohibition under section 211(c)(1) of the Act, state fuel controls respecting the same fuel characteristic or component as the federal regulation are preempted. A state may only adopt and enforce such a fuel control if it is approved by EPA as a SIP revision, after a showing that it is necessary to achieve the NAAQS that the plan implements.

Prior to December 15, 1993, EPA had issued regulations under section 211(c)(1) that control the lead content and volatility of gasoline. State controls for these gasoline characteristics or components are subject to the above preemption provision.

The reformulated and conventional gasoline regulations were issued under the authority of both section 211(c)(1) and 211(k). State controls respecting the gasoline characteristics or components controlled or prohibited in the RFG and conventional gasoline regulations are therefore preempted, like state volatility and lead content controls. In general, the gasoline characteristics or components controlled or prohibited under these federal regulations vary depending on the program (RFG or conventional) and the model (simple or complex).(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)