Power company Wisconsin Public Service (WPS) will invest about $300 million to upgrade a couple of coal plants in Wisconsin and pay a $1.2 million penalty, among other things, to resolve violations of the Clean Air Act, two federal agencies said on Friday.

The company, a unit of Integrys Energy Inc of Chicago, also agreed to spend $6 million on environmental mitigation projects, the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Justice said in a statement.

Kerry Spees, a spokesman at WPS, told Reuters the EPA and the utility had been working for years to come to the settlement, which was related to a New Source Review issue.

New Source Review, or NSR, is an approvals process under the Clean Air Act that requires a pre-construction review by the EPA when a business proposes building a new facility or modifying an existing facility that would create a significant increase in regulated pollutants.