The U.S. Environmental Protection Agency has asked the U.S. Court of Appeals for the District of Columbia Circuit to lift a stay on the cross-state air-pollution regulation and delay compliance deadlines by three years.

The U.S. Supreme Court on April 29 upheld EPA's authority to issue the rule, which requires several states and the district to develop plans to curb air pollutants that travel downwind to other states. The rule is significant for engineering and construction firms that help states develop implemen- tation plans and utilities install pollution-control equipment.

The appeals court ruled in December 2011 that EPA could not move forward with the regulation and should continue to implement the George W. Bush administration's Clean Air Interstate Rule until the EPA develops a replacement for the cross-state regulation.

In its June 26 motion, EPA said the appellate court should lift its stay on the rule in light of the Supreme Court's ruling. If the court grants EPA's request, the cross-state rule's first compliance deadlines would begin in 2015.