The lawsuit, filed March 31, 2026, targets the administration's rollback of the 2024 Mercury and Air Toxics Standards (MATS) Rule, which implements nationwide standards that limit emissions of toxic air pollutants from coal- and oil-fired power plants, including mercury, arsenic, lead and other toxic metals, in addition to acid gases, such as hydrogen chloride and formaldehyde.
The Environmental Protection Agency updated the standards in 2024 following significant developments in pollution control technologies. Last month, the Trump administration rolled back the updated standard, allowing for more of these dangerous emissions to be released into the air.
"Again and again, Trump is selling out our health and environment to enrich his fossil fuel friends. 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," said Attorney General Tong.
While mercury and other hazardous air pollutants disproportionately harm people who live near coal- and oil-fired power plants, the emissions can also travel great distances and be deposited into other states. Mercury is a potent neurotoxin that poses serious dangers to public health, especially for pregnant women and children. A pregnant person's consumption of mercury exposes their child to mercury and can cause lifelong developmental harms and neurological disorders such as seizures, vision and hearing loss, or delayed development. Exposure to mercury also increases the risk of cardiovascular disease, diabetes and autoimmune dysfunction in adults.
Mercury emissions from power plants are also a major contributor to mercury contamination in U.S. waterways, harming the local commercial and recreation fishing economies, as well as tribal nations and indigenous peoples that rely on fishing for subsistence.
The coalition argues that the repeal is unlawful because the EPA has 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failed to adequately consider developments in practices, processes and control technologies in its attempt to revert to outdated standards.
Illinois Attorney General Kwame Raoul and Minnesota Attorney General Keith Ellison led the coalition. Joining them are 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 representing Connecticut in the matter.