Northern Indiana Public Service Co. will be responsible for cleaning up soil contamination at individual residences within the Town of Pines Groundwater Plume Superfund site in Porter County, Indiana, the Environmental Protection Agency announced today.

The soil is contaminated by coal ash, the byproduct of burning coal for coal for electricity. For decades, NIPSCO dumped more than a million tons of coal ash in a landfill on top of the Town of Pines aquifer, and it also offered coal ash to the Town of Pines to be used in landscaping homes and building roads, saying it wasn’t harmful to residents.

The coal ash leached into the ground water, causing the town’s well water to be polluted. NIPSCO paid for homes within the remedial investigation area to be hooked up to the Michigan City municipal water, but other homes remained on well water.

It is estimated it will cost $11.8 million to resolve the Superfund liability.

“This settlement requires NIPSCO to remove soil contaminated with coal ash from the utility’s power generation facility, and to monitor groundwater in and around the Town of Pines, Indiana,” said Larry Starfield, acting assistant administrator for the EPA’s Office of Enforcement and Compliance Assurance in a news release. “This cleanup work will help protect residents from exposure to arsenic and other hazardous substances.”

Indiana attorney general Todd Rokita said Hoosiers will benefit from NIPSCO’s commitment to reimburse taxpayers for public money spent on the long-standing cleanup discussion and process.

“They stand to benefit, as well, from the company’s pledge to finish the cleanup in the Town of Pines made necessary by disposal of its coal ash in residential areas,” Rokita said. “We must always work to protect Hoosiers and uphold the rule of law.”

The consent decree will require NISPCO to excavate any residential areas with soil contamination levels elevated above EPA standard cleanup levels. NIPSCO will remove the contaminated soil and transport it to a licensed waste disposal facility.

NISPCO will also be responsible for restoring properties with clean soil and monitoring residential drinking wells, surface water and groundwater monitoring to make sure contamination hasn’t migrated beyond the excavated area.

The EPA and State of Indiana will oversee the cleanup, and NISPCO will be required to pay for any costs incurred.

This story will be updated.