The Sierra Club sued, arguing the wildfire smoke did not meaningfully change ozone readings and that the Michigan Department of Environment, Great Lakes and Energy failed to analyze how local pollution sources contributed to the ozone levels on those days. The environmental advocacy group also challenged the EPA’s finding that the region met federal standards for ozone pollution.

White determined the exceptional events designation was appropriate, siding against the Sierra Club in deciding the EPA and EGLE correctly analyzed the smoke’s impact on ozone readings in June 2022.

She sided against EPA in deciding the EPA was wrong to put Michigan back into attainment for ground-level ozone without Michigan adopting control measures that would cut volatile organic compounds, which contribute to ozone pollution.

EPA determined the Detroit area was out of attainment for ground-level ozone on April 13, 2022. Michigan regulators did not impose control technologies for ozone-causing pollutants by the deadline in early 2023. Instead, they asked EPA to redesignate the area as in attainment with the air quality rules.

Michigan was obligated to implement control technologies even though it had submitted a redesignation request, White said in her order. Control technologies include efforts to reduce volatile organic compounds from being released from manufacturing plants and industrial sources, according to EPA documents.

Sierra Club member and Detroit environmental justice activist Dolores Leonard cheered the outcome of the case.

“Without this victory, EPA’s decisions would have let Michigan avoid the rules needed to reduce pollution and keep the air we breathe safe,” Leonard said. “At a time when asthma rates are rising in Detroit, especially in Black communities, that’s unacceptable. With the backing of this federal court decision, our community will continue to push the state of Michigan to take much-needed action to relieve ozone pollution in this area.”

The Clean Air Act requires those pollution control measures to be implemented even after the EPA puts an area back into attainment to ensure the air quality remains healthy, said Nick Leonard, executive director of Great Lakes Environmental Law Center, which argued the Sierra Club’s case.

White’s order means the EGLE will have to reapply for the attainment of the ozone standard, Leonard said.

“At the very least, I would say they have to correct the legal deficiency, which was that they didn’t enact the pollution control rules that are typically required for areas that are in non-attainment for this long,” he said.