The U.S. Environmental Protection Agency said it intends to officially determine that Porter County has met the federal standards for sulfur dioxide air emissions.

The EPA said it will designate the county as being in “attainment” of the 2010 National Ambient Air Quality Standard for Sulfur Dioxide after air monitor readings in the area near the ArcelorMittal Burns Harbor steel mill met air quality standards between 2017 and 2019.

“Thank you for Indiana’s efforts to provide cleaner air in your state. We look forward to a continued dialogue with you and your staff as we work together to complete the area designations and implement the 2010 SO2 NAAQS,” wrote EPA Region 5 Administrator Kurt Thiede.

The designation means the county’s sulfur dioxide levels are cleaner than the national standard, exempting the state and pollution sources in the area from additional monitoring and reporting requirements.

The agency’s decision is the result of a recommendation sent to the EPA in April by Indiana Department of Environmental Management Commissioner Bruno Pigott.

IDEM reported that monitoring data collected at ArcelorMittal Burns Harbor and at the town of Dune Acres between 2017 and 2019 reported yearly sulfur dioxide values below the federal 75 parts per billion sulfur dioxide standard.

“Indiana’s recommendation is supported by a thorough analysis of the quality assured, certified SO2 monitoring data, as well as previous modeling that demonstrates the SO2 monitoring network and SO2 monitoring data for Porter County are sufficient for the purpose of the area’s designation of ‘attainment/unclassifiable’ under the standard,” Pigott wrote.

Before the designation for Porter County and 44 other areas from across the U.S. are finalized by the EPA, states and the public will have until September 21 to submit comments about the decision to the agency.

Federal regulations and state enforcement of those regulations have helped limit the amount of sulfur dioxide pollution from Porter County for decades.

The Clean Air Act of 1970 allowed the federal government to establish national standards for air pollutants and direct states to establish state implementation plans that tell the EPA what the state, territory or local air district plans to do to meet those standards.

The EPA approved the first sulfur dioxide State Implementation Plan for Dearborn, Gibson, Lake and Porter Counties in 1988.

The plan, like all approved state implementation plans, was codified into Indiana state law. It placed limitations on the counties’ major source for sulfur dioxide emissions.

In Porter County, the major source for sulfur dioxide emissions is the steel mill now owned by ArcelorMittal Burns Harbor, LLC.

The facility had to switch some boilers and furnaces to burn only natural gas. The state also placed hourly sulfur dioxide emission limitations and operation limitations on facilities crucial to steel mill operations like its sinter plant, blast furnace stoves, coke batteries and slab mill soaking pits.

Since then, the facility has only been formally cited for sulfur dioxide plan violations in 1999 and 2005, but the company has fought to weaken the regulation.

ArcelorMittal spent $3,700 in political contributions during 2008 and 2009, including $1,000 to Gov. Mitch Daniels’ reelection campaign and another $1,350 going to environmental affairs committee members in the Indiana House and Senate.

The following year, the state of Indiana amended its state implementation plan for sulfur dioxide in Porter County to remove the sulfur dioxide emission limit for ArcelorMittal Burns Harbor’s blast furnace flare and submitted it to the EPA for final approval.

“The SO2 emission limits established in this rule for processes using the blast furnace account for all of the available blast furnace gas; therefore, the emission limit for the blast furnace gas flare is redundant and unnecessary to assure continued protection of the National Ambient Air Quality Standard for SO2 in Porter County. Removing the SO2 blast furnace gas flare limit from 326 IAC 7-4-14 will not result in or allow an increase in actual SO2 emissions,” the agency’s then-Commissioner Thomas Easterly wrote to the EPA.

In 2014, the EPA formally rejected the state’s revision, saying it would violate portions of the Clean Air Act.

“Removal of the flare limit eliminates the only requirement which directly addresses the sulfur content of the blast furnace gas which ArcelorMittal uses to fuel other combustion units in the facility. Although blast furnace gas is considered to be a low-sulfur fuel, the state’s submittal indicates that the sulfur content of blast furnace gas can vary, and the proposed SIP revision would allow ArcelorMittal’s blast furnace gas to increase in sulfur content without limit. This would be inconsistent with the state’s prior attainment demonstration for the SO2 NAAQS,” the agency wrote.

ArcelorMittal sued for a review of the EPA’s decision. The state joined the company in the suit a month later.

More than five years later, in 2019, the company, the state and the federal government settled the suit.

The state was not allowed to remove the blast furnace flare limit. Instead, the settlement would allow ArcelorMittal to emit seven times the amount of sulfur dioxide previously allowed. In exchange, the federal government required a 90% drop in sulfur dioxide emissions limits for several minor furnaces and boilers, and a 15% emission limit reduction in Power Station Boilers No. 8, 9, 10, 11 and 12.

It’s unclear how the settlement will affect sulfur dioxide levels in Porter County and beyond.

Earlier this year, ArcelorMittal also settled a lawsuit filed by the federal government and the states of Indiana and Ohio over multiple alleged violations of the Clean Air Act at several facilities, including at Burns Harbor.

Some of the charges include excess visible emissions from the sinter plant windbox gas recirculation system and coke battery underfires, which are regulated by the state’s sulfur dioxide plan.

The company agreed to pay a civil penalty of $5,002,158, including more than $2 million paid to the state of Indiana, and adopt a series of controls and programs to get the facilities involved in the settlement back within Clean Air Act requirements.