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Indianapolis Power & Light Settlement Information Sheet

(WASHINGTON – August 31, 2020) The United States announced today that Indianapolis Power & Light Company (IPL) has agreed to resolve alleged violations of the Clean Air Act and Indiana law by undertaking measures to improve its environmental compliance at the Petersburg Generating Station, in Pike County, Indiana.  The State of Indiana is also a party to today’s agreement.


Indianapolis Power & Light Company, a subsidiary of AES and also known as IPL, is a utility company providing electric service to the City of Indianapolis. IPL provides electric service to more than 470,000 customers. IPL is the owner and operator of the Petersburg Generating Station.

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During 2008, 2015, and 2016, EPA and the Indiana Department of Environmental Management conducted investigations of the Petersburg Generating Station. Based upon information obtained during the investigations, EPA issued three Findings and Notices of Violation to IPL for the following Clean Air Act violations: (1) failure to obtain a permit and install controls as required by Prevention of Significant Deterioration provision and the Indiana State Implementation Plan (SIP) and (2) emissions in excess of opacity standards under the New Source Performance Standards for Fossil-Fuel-Fired Steam Generators, Subpart D, the Indiana SIP, and the Petersburg Generating Station’s Title V Operating Permit.

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Injunctive Relief

The settlement requires IPL to reduce the Petersburg Station’s emissions of nitrogen oxides (NOx), sulfur dioxide (SO2), particulate matter (PM) and sulfuric acid mist (H2SO4 or SAM).  IPL will install a pollution control device known as a Selective Non-Catalytic Reduction System (SNCR) on one of the plant’s coal-fired units, upgrade its sulfuric acid mitigation system, and continually operate all of its pollution control equipment to meet levels that will achieve reductions in NOx, SO2, PM and H2SO4 emissions.  

The agreement recognizes that IPL may permanently retire two of its Petersburg units earlier than it had planned.  Retirement of those units would result in emission reductions significantly greater than any reductions achieved by installing and operating the SNCR.  Thus, IPL may forego installing that control device if it in fact retires the two units prior to July 1, 2023, the deadline under the agreement by which IPL must install the SNCR.

Under the agreement, IPL will also undertake a project costing $5 million to mitigate the harm to the environment caused by the plant’s excess emissions over the years.  IPL will submit a proposal to EPA and the State to construct and operate a system that will provide a new, non-emitting source of power at an on-site location known as the auxiliary electrical unit.  The new source of power is expected to reduce emissions of SO2, NOx and PM from that unit. 

In addition, at the request of Indiana, IPL will expend $325,000 to undertake a state-only environmentally beneficial project designed to restore and preserve some ecologically significant parcels of land near the plant.

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Pollutant Impacts

Full implementation of the settlement will result in emission reductions of SO2, NOx, H2SO4/PM by 58,055, 4,532, and 2,630 tons per year, respectively.

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Health Effects and Environmental Benefits

  • The pollutants reduced under this settlement have numerous adverse environmental and health effects. Sulfur dioxides and nitrogen oxides can be converted to fine particulate matter once in the air. Fine particulates can be breathed in and lodged deep in the lungs, leading to a variety of health problems and even premature death. Other health and environmental impacts from the pollutants addressed in this settlement include the following:

  • Sulfur dioxide – High concentrations of SO2 affect breathing and may aggravate existing respiratory and cardiovascular disease. Sensitive populations include asthmatics, individuals with bronchitis or emphysema, children, and the elderly. Sulfur dioxide is also a primary contributor to acid deposition, or acid rain.
  • Particulate matter – Short term exposure to particulate matter can aggravate lung disease, cause asthma attacks and acute bronchitis, may increase susceptibility to respiratory infections and has been linked to heart attacks.
  • Nitrogen oxides – Nitrogen oxides can cause ground-level ozone, acid rain, particulate matter, global warming, water quality deterioration, and visual impairment. Nitrogen oxides play a major role, with volatile organic chemicals, in the atmospheric reactions that produce ozone. Children, people with lung diseases such as asthma, and people who work or exercise outside are susceptible to adverse effects such as damage to lung tissue and reduction in lung function.
  • Sulfuric Acid Mist – SAM is a corrosive chemical and can severely burn the skin and eyes. It may cause third degree burns and blindness on contact. Exposure to SAM can irritate the eyes, nose, throat and lungs, and at higher levels can cause a buildup of fluid in the lungs (pulmonary edema). Asthmatics are particularly sensitive to the pulmonary irritation. Repeated exposures may cause permanent damage to the lungs and teeth. 

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Civil Penalty

IPL will pay a total civil penalty of $1.525 million, of which $925,000 will go to the United States and $600,000 to the State of Indiana.

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Comment Period

The proposed settlement, lodged in the U.S. District Court for the Southern District of Indiana, is subject to a 30-day public comment period following notification in the Federal Register and to final court approval.  Information on submitting comment is available at the Department of Justice.

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Contacts for Further Information

Sabrina Argentieri
Air Enforcement Division
U.S. Environmental Protection Agency
1200 Pennsylvania Ave., NW (Mail Code 2243A)
Washington, DC, 20460
(202) 564-8953

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