The Environmental Protection Agency advised states on Monday that it is working on a plan to give them more flexibility in complying with the Obama administration's rules for disposing of the ash waste from coal-fired power plants.

EPA Administrator Scott Pruitt sent a round of letters to states informing them that the agency is working on a "guidance" for states to set up their own permitting programs to regulate the safe disposal of coal ash and promote its beneficial uses.

Advocates of the rules have said the change will weaken the coal regulations at the federal level by allowing states to dictate the terms of compliance as long as they have rules that are similar to EPA's.

"EPA expects that its new guidance will allow for the safe disposal and continued beneficial use of coal ash, while enabling states to decide what works best for their environment," the agency said. Coal ash is used in a number of products for the building industry, such as dry wall, bricks and concrete.

The Obama coal ash regulations have made it increasingly difficult and costly to handle the waste from coal power plants, prompting critics to include them in Obama's "war on coal."

"EPA continues to support the environmentally sound recycling of coal ash," Pruitt said. "Through the authority granted by Congress in the [Water Infrastructure Improvements for the Nation] Act, EPA is issuing this guidance to promote the swift submission and review of state permit programs, make state and federal management of coal ash more consistent, and place enforcement in the hands of state regulators – those who best know the needs of local communities."

The water infrastructure bill that was passed last year authorizes the states to set up their own permit programs for coal ash permit. Without the changes, the states would be subject to civil litigation from environmental groups as the only enforcement mechanism.