The Environmental Protection Agency is once again changing America’s gasoline rules in an effort to increase fuel supplies and bring down prices at the pump. This time, it means allowing more volatile gasoline to reach consumers earlier than it normally would.
Beginning September 1, the EPA will temporarily relax federal gasoline volatility requirements, effectively bringing winter-grade fuel into the market roughly two weeks before the summer control season normally ends on September 15. The agency says the move could add hundreds of thousands of barrels of gasoline per day to the available domestic supply.
The downside is that winter gasoline is more volatile, meaning it evaporates more readily. That characteristic helps engines operate in cold weather, but during hot conditions, additional fuel vapors can contribute to ground-level ozone and smog.
The EPA says it issued the emergency waiver after consulting with the Department of Energy and determining that unusual fuel-supply circumstances justified the move under the Clean Air Act. It’s the latest in a series of fuel waivers the agency has used throughout 2026 as it tries to keep gasoline supplies up and prices down.
Why Summer And Winter Gas Are Different
Gasoline formulations change throughout the year largely because temperature affects how readily fuel evaporates. Volatility is commonly measured using Reid Vapor Pressure, or RVP, with higher numbers indicating gasoline that evaporates more easily.
Summer gasoline is formulated with a lower RVP because high temperatures already encourage evaporation. Reducing volatility helps limit emissions of volatile organic compounds, which can react with nitrogen oxides in sunlight to form ground-level ozone.
Winter gasoline can have a higher RVP because colder temperatures make fuel less prone to evaporating. Allowing that higher-volatility gasoline onto the market early can increase supply flexibility, although doing so while temperatures remain high comes with an environmental tradeoff.
The EPA Says More Gasoline Should Mean Lower Prices
According to the EPA, its September waiver will allow E10 gasoline containing 10 percent ethanol to be sold at a higher RVP. The agency estimates that ending summer-blend requirements early will increase domestic gasoline availability by hundreds of thousands of barrels per day.
EPA Administrator Lee Zeldin said the move is intended to “increase supply and lower gas prices,” while Energy Secretary Chris Wright similarly argued that expanding gasoline supply should provide relief for American families.
Exactly how much motorists will save isn’t specified. Pump prices depend on numerous factors beyond fuel-blend requirements, including crude oil prices, refinery output, transportation costs, regional inventories, and taxes, so the waiver doesn’t guarantee a particular reduction.
The Environmental Tradeoff
The reason these restrictions exist in the first place is air quality. Higher-volatility gasoline evaporates more readily in warm weather, potentially increasing the emissions that contribute to ozone formation.
September can still bring high temperatures across large parts of the country, particularly in southern and western states, which means pulling winter-grade gasoline forward could increase emissions compared with keeping the normal summer requirements in place.
EPA is also waiving state-level controls in Texas, Arizona, and California that ordinarily extend beyond September 15. Those exemptions can remain in effect for up to 20 days, with the agency saying it will continue monitoring fuel supplies and could issue additional waivers if necessary.
This Isn’t The First Fuel Rule Change Of 2026
The September change follows several emergency measures already introduced this year. EPA says nationwide waivers have been in effect since May 1, with subsequent extensions changing ethanol-blending and gasoline-volatility restrictions.
Under its August 20 action, the agency also extended provisions allowing gasoline containing up to 15 percent ethanol and reinstated a one-psi RVP allowance for ethanol blends in states where it had previously been removed. Existing volatility waivers continue through August 31 before the wintertime limits are brought forward beginning September 1.