The American Fuel and Petrochemical Manufacturers and the Western States Petroleum Association petitioned the U.S. Court of Appeals for the District of Columbia Circuit June 11 to review an Environmental Protection Agency requirement that the domestic fuel supply include specified amounts of commercially scarce cellulosic biofuels in 2011. The agency decided in May not to waive the requirement, despite acknowledging the scarcity of the fuels, which means refiners and importers must purchase credits or carry over the requirements to the next year.