The coalition argues the repeal is unlawful because the Environmental Protection Agency "failed to provide a reasoned basis for it and failed to adequately consider developments in practices, processes and control technologies in its attempt to revert to outdated standards," the office said. The attorneys general are asking the court to declare the rule unlawful and reverse it.
The 2024 MATS Rule updated nationwide standards for hazardous air pollutants from power plants, including mercury, arsenic, lead, hydrogen chloride and formaldehyde, the press release said. The EPA tightened those standards in 2024 "following significant developments in the technologies used to control pollution." The Trump administration rolled the standards back last month.
"Again and again, Trump is selling out our health and environment to enrich his fossil fuel friends," Tong said in the release. "Big Oil knows how to limit these toxic pollutants. It's not hard or particularly costly. Trump just doesn't care. We're suing today to protect Connecticut families from lifelong developmental harm and disease."
The office described mercury as "a potent neurotoxin that poses serious dangers to public health, especially for pregnant women and children." According to the release, a pregnant person's consumption of mercury can expose a child to the substance and "cause lifelong developmental harms and neurological disorders such as seizures, vision and hearing loss, or delayed development." The office said exposure also increases risks of cardiovascular disease, diabetes and autoimmune dysfunction in adults.
The release said mercury emissions from power plants are "a major contributor to mercury contamination in U.S. waterways," harming commercial and recreational fishing economies and tribal nations that rely on subsistence fishing. Emissions can travel across state lines, it said.
Illinois Attorney General Kwame Raoul and Minnesota Attorney General Keith Ellison led the coalition, the release said. Joining them were the attorneys general of Arizona, Delaware, the District of Columbia, Maine, Maryland, Massachusetts, Michigan, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, Washington and Wisconsin, along with the city of Chicago, the city of New York and Harris County, Texas.
Assistant Attorney General Scott Koschwitz and Deputy Associate Attorney General Matthew Levine, Chief of the Environment Section, are assisting Tong on the matter, the office said.