The California Air Resources Board says refineries can begin producing and selling winter-blend gasoline.
The blend is usually not sold until October 31st because it’s a more volatile compound and its quick evaporation can harm air quality during hot weather.
But Governor Jerry Brown requested the early switch because of the recent gas price spikes.
The Board’s Dave Cleggern says with the cooler weather he doubts it will have any negative environmental effect.
"We don’t believe there will be any impact on the federal standards that we have to meet for air quality and we’re fairly sure that the impact on state requirements will be small."
Cleggern says the early switch has only happened a few times before; once after Hurricane Katrina and another time after a refinery fire.
He says the early transition could increase fuel supply by 8 to 10 percent, which could lower fuel prices.