(AP) — It’s a dilemma for drivers.

Do they choose a gasoline that’s cheaper and cleaner even if, as opponents say, it could damage older cars and motorcycles?

That’s the peril and promise of a high-ethanol blend of gasoline known as E15. The fuel contains 15 percent ethanol, well above the current 10 percent norm sold at most U.S. gas stations.

The oil industry’s chief lobbying group has asked the Supreme Court to block sales of E15, saying the high-ethanol blend could leave millions of drivers with broken down vehicles and high repair bills. The ethanol industry calls that a scare tactic and notes that no documented cases of engine damage have been caused by ethanol.

The court could decide as soon as Monday whether to hear the case.