– The Supreme Court dealt a big blow to the oil industry Monday, deciding not to hear a legal challenge of the federal government’s decision to approve the sale of fuel containing 15 percent ethanol.

The decision not to hear the case — which the high court issued without comment — was a defeat for the American Petroleum Institute and several other groups that have been fighting the Environmental Protection Agency’s 2010 approval of the E15 blend. Although the agency greenlighted the sale of E15 for cars and trucks made since 2007, the higher-ethanol blend is not authorized for older vehicles.

After the U.S. Court of Appeals for the District of Columbia ruled in January that the American Petroleum Institute and more than a dozen other groups did not have standing to challenge the EPA’s limited approval of E15, the institute and other parties appealed to the Supreme Court.

Harry Ng, the institute’s vice president and general counsel, called the high court’s move “a big loss for consumers, for safety and for our environment.”

The oil industry argues that E15 has not been proved safe, that “misfueling” could cause filling station owners to face liability when the fuel is inadvertently pumped into older cars and that the market for the mix is limited, especially since some automakers have warned drivers that using the fuel will void warranties.

Biofuel backers cheered the decision.

Tom Buis, the CEO of Growth Energy, which originally petitioned the EPA to approve the 15 percent blend, called the ruling “a true victory for the American biofuels industry” as well as consumers, the economy and the environment.