The US Environmental Protection Agency is revising a 2012 proposal following intense opposition from the industry.

Ahead of the release of the rules on September 20, information about their scope has leaked by people who have been briefed on the plan.

According to Bloomberg, a person familiar with the plan said the agency had proposed retaining a provision letting utilities phase-in the CCS technology over time.

EPA spokeswoman Alisha Johnson declined to comment on the specific numbers but told The Wall Street Journal that the agency was working on its revised rule "in light of important comments received by the agency and in a way that considers the viewpoints of all stakeholders".

She said the agency was on track to complete the rules by the fast-approaching deadline.

The EPA has also been directed to draft carbon limits for existing power plants by June of next year that will ultimately be finalized in 2015.

According to Bloomberg, lobbyists for coal producers such as Peabody Energy and Arch Coal and utilities such as American Electric Power have visited the Office of Management and Budget, which is reviewing the EPA proposal, making their case that requiring CCS is a mistake.

“By prohibiting the use of coal without CCS, demand for electricity would be met with natural gas or other cost-competitive available options but not coal with CCS, which will remain significantly more expensive,” the Coal Utilization Research Council said in a filing to the White House.

The nation has more than 1142 coal-fired plants and 3967 gas-fired plants across the country, with many coal-fired units transitioning to the latter.

About 37% of all of US electricity is generated from coal, with some states, such as West Virginia, relying almost totally on coal for electricity generation.

When Obama’s carbon action plan outlining the arrangements was announced in June, American Coalition for Clean Coal Electricity spokeswoman Lisa Miller said Obama’s expected proposal was unworkable.

“Even brand new, state-of-the-art plants wouldn’t be able to meet these regulations,” she said.