EDEN, N.C. (AP) - Two years after one of the worst coal ash spills in U.S. history, the country's largest electricity company is digging up and hauling away the residue.

EDEN, N.C. (AP) Two years after one of the worst coal ash spills in U.S. history, the country's largest electricity company is digging up and hauling away the residue.

The 2014 disaster polluted a river that runs through North Carolina and Virginia and led legislators to order Duke Energy Corp. to close all 32 of its coal ash pits in North Carolina by 2029. It's also closing its South Carolina pits.

The bill for a long-delayed cost of burning coal for power could burden consumers for years.

Duke Energy faces about $4 billion in cleanup liabilities in the two states. If it's all passed along to ratepayers, accountants at the state agency that represents consumers calculate North Carolina households could see rates rise by an average of about $18 a year.