A NiSource Inc. (NI) utility unit finalized a settlement with the U.S. Environmental Protection Agency, agreeing to invest $600 million in environmental, conservation initiatives, and clean energy programs in northern Indiana.

The settlement is the 17th reached by the EPA and the Department of Justice as part of a national initiative to control emissions from coal-fired power plants under the Clean Air Act's New Source Review requirements. In addition to the investment, NiSource will pay a $3.5 million civil penalty.

The company said the settlement follows a 2004 notice that alleged NiSource's NIPSCO business made upgrades or modifications to its generating facilities in the 1980s and 1990s without obtaining the proper permits.

NIPSCO, one of nine energy distribution companies owned by NiSource, was among more than 50 U.S. electric companies that received a violation notice since 1998 as part of the EPA initiative. The company maintained that it acted in accordance with the regulations and conducted "only routine maintenance and upgrades on the units."

The settlement resolves all matters related to the EPA's review and future claims through 2018.

NiSource said the settlement included environmental controls and clean air technology that will further reduce nitrogen oxide, sulfur dioxide and particulate matter emissions at the company's coal-fired electric generation facilities.

The Midwest and Northeast electricity and natural-gas utility has benefited from cost-cutting and has seen signs of demand improving in some markets. NiSource in October reported it swung to a third-quarter profit as demand for gas distribution and electricity grew, while year-earlier results were hurt by cooler demand and higher pension expenses.

Shares were up 2 cents to $18.34 in recent trading.

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