The U.S. Supreme Court on Friday sided with three small oil refineries seeking exemptions from requirements to blend ethanol into their gasoline. The decision overturns an appellate court ruling from last year. The ruling sets a precedent, giving the U.S. Environmental Protection Agency more leeway in granting exemptions to oil refineries to rules intended to promote the use of corn-based ethanol and other fuel made from renewable sources. Last year, the 10th U.S. Circuit Court of Appeals ruled that the refineries can only qualify for an exemption if they’ve been continuously exempt already. But in a 6-3 decision, the high court ruled refineries can seek extensions even if they wait until an earlier waiver has lapsed. The justices compared it to a student asking their professor for an extension for a big paper after it’s due.