On April 1, four separate suits were filed against the Environmental Protection Agency (EPA) in the U.S. Court of Appeals for the District of Columbia Circuit over a January 30 final rule regarding backup stationary engines. The rule allows these generators to operate for up to 100 hours during peak-use periods and emergencies without emissions controls. The EPA explained this rule lets internal combustion engines participate in emergency demand programs. The suits are expected to be combined; the petitioners are the Conservation Law Foundation, Delaware Department of Natural Resources and Environmental Control, First Energy Solutions Corp., and the National Rural Electric Cooperative Association.