RALEIGH, N.C. -- Duke Energy will pay an $84,000 penalty and work to end leaks of potentially toxic waste from three North Carolina coal-burning power plants into groundwater and nearby rivers.

Related: Duke Energy Offers $5K Compensation For Coal Ash Neighbors

A deal announced Tuesday and signed by a Duke Energy executive includes the penalty for leaks detected at pits holding liquefied coal ash at the Rogers, Allen and Marshall power plants.

Coal ash is the residue left after decades of burning coal to generate power. It can contain toxic materials like arsenic and chromium.

Related: Duke Energy Wants To Increase Rates For Coal Ash Cleanup

The agreement with the state regulator settles pollution law violations involving nearly leaky spots detected before 2015 that allow tainted waste into groundwater and the adjoining Catawba and Broad rivers.

Related: All Duke Energy Coal Ash Ponds Must Close by 2024

Southern Environmental Law Center attorney D.J. Gerken said the deal commits the country's largest electricity company to stop the pollution.

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