BOSTON — Massachusetts Attorney General Maura Healey is pledging to sue the Trump administration over its move to kill an Obama-era effort to limit carbon emissions from coal-fired power plants.

Healey, a Democrat, said the decision violates the law and imperils the future of the planet.

Environmental Protection Agency Administrator Scott Pruitt said Monday he would be issuing a new set of rules overriding the Clean Power Plan, the centerpiece of President Barack Obama’s drive to curb global climate change.

Healey said it’s “essential that the EPA address our country’s largest source of carbon pollution — existing fossil fuel-burning power plants — to mitigate climate change.”

She said Massachusetts fought for years to help put the rule in place.

Healey said Massachusetts, with its partners, will be suing to protect the plan.