By Laura Barron-Lopez - 06/30/14 12:26 PM EDT
The Supreme Court on Monday declined to hear a challenge from oil companies to a California law mandating fuel producers lower the amount of carbon pollution emitted from fuels in the state.
The justices turned away an appeal from fuel makers that claim the law unfairly targets out-of-state producers.
But out-of-state oil refiners and companies argue the law gives in-state producers an unfair advantage when placing a higher "carbon-intensity" rating on fuels transported into California from other states, The Associated Press reports.
The Supreme Court's refusal to hear the challenge keeps the ruling from the 9th U.S. Circuit Court of Appeals in place, which stated the law affords fuel producers options for getting their product to market.
California's law is the first of its kind in the U.S.