Renewable Fuel Standard & E15 RVP Waiver

Current understanding

Under the Clean Air Act, gasoline blended with 10% ethanol (E10) has a 1-psi Reid Vapor Pressure (RVP) volatility waiver that allows summer sales, while 15% ethanol blends (E15) lack an equivalent waiver, creating seasonal and state-by-state restrictions on E15 sales. Legislation and EPA actions have periodically sought to extend the waiver to E15 for year-round nationwide sales, with proponents citing lower pump prices and biofuel demand and opponents raising volatility, small-engine compatibility, and refinery compliance concerns. The Renewable Fuel Standard (RFS) framework separately governs blending obligations and includes small refinery hardship exemptions and RIN credit mechanics that are often adjusted alongside blend-level policy.

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