On March 15, power companies pushed the Environmental Protection Agency (EPA) to reconsider its new power plant carbon dioxide performance standards, originally released in April 2012. Industry called on EPA to include emissions limits based on fuel type, particularly distinguishing between coal and natural gas sources as well as between base load and cycling units. The proposed standards are the first instance of performance standards placing all fuel sources in a single category. Environmental groups, hoping the rule will translate into regulating existing power plants, warn that reissuing the proposal would create delays.