That means the rules won't full take effect until long after President Barack Obama leaves office. The delay raises questions about the fate of the landmark rules under the next administration.
The new rules seek to cut carbon emissions from power plants by 30 percent by 2030. But states are being given flexibility to develop their own plans for meeting their targets.
Obama initially wanted states to submit their plans by mid-2016. But details of the proposal obtained by The Associated Press show states could have until 2017 to submit a complete plan. If they join with other states, they could have until 2018.