A nonprofit environmental group has filed a second lawsuit demanding a power company immediately stop polluting Illinois’ only federally designated Wild & Scenic River with coal ash, a toxic byproduct of burning coal. The coal is stored in unlined pits on the grounds of a retired Central Illinois power plant owned by the Texas-based company Vistra. The pits sit on the banks of a 17-mile stretch of the state’s Little Vermilion River, known as the Middle Fork.

A pending lawsuit from the same group, Prairie Rivers Network, was filed under the Clean Water Act, alleging the contamination of surface waters on the river. That case is in a holding pattern while federal courts consider whether contamination that enters a river through groundwater, rather than through direct pollution, is covered by the Clean Water Act.

Jenny Cassel, an attorney with Earthjustice, which filed the new lawsuit on behalf of Prairie Rivers Network, says the water can’t wait for the courts to make a decision around which types of contamination are covered under which law.

“We’re not just going to sit here and wait for that legal determination to be made while that contamination continues to happen,” Cassel said. “We’re making use of the tools that are available to us through the Illinois Environmental Protection Act to try to get this pollution permanently stopped as soon as possible.”

The suit alleges Vistra is continually violating a number of environmental protection laws by allowing the coal ash, which contains toxic chemicals including arsenic, lead, boron and manganese, to seep into ground and surface water on an ongoing basis. The group is asking the Illinois Pollution Control Board to demand the company that owns the ash pay penalties, clean it up and modify its practices for disposing of toxic waste.

The rust-colored pollution is clearly visible from the river.

“It’s a problem because this is real life, real-world threats, real pollution that is ever-polluting our groundwater and our lakes,” said Cassel. “Until one of our branches of government takes action to stop it, Illinois residents and our waters are paying the cost.”

Last year, Vistra released a statement regarding its proposal to stabilize the riverbank in order to prevent risk of a major coal ash spill and mitigate the toxic waste seepage.

“The wild card is the timing of the regulatory approvals combined with ongoing intervention by outside groups intent on slowing it down for their own agenda,” the statement reads.

Advocates say a riverbank stabilization project would be a short-term way for the company to address the ongoing pollution, without having to extract and move the ash, a long-term but costly solution. Vistra did not respond to requests for comment about an updated plan for the coal ash pits or about the new lawsuit.

Although removing coal ash can be expensive, cleaning up spills and breaches has proved more costly: The cleanup following a breach at a plant run by the Tennessee Valley Authority in 2008 in Kingston, Tenn., cost upwards of $1.2 billion. Dozens of workers who helped clean up that site since died from ailments linked to exposure to coal ash.

The national organization America’s Rivers deems the threat of massive contamination incident so imminent that it named the Middle Fork one of the country’s most endangered waterways of 2018.

Cassel says Illinois has the largest number of coal ash reservoirs of any state, and because the riverbank between the coal ash and the Middle Fork is eroding, the risk of a spill is a real concern.

“We’re sort of the epicenter of the coal ash problem and with ever increasing floods from climate change this is not a problem that’s going to go away,” Cassel said. “We have to deal with it if we’re not going to have generations of people canoeing through or drinking waters that are full of toxic contaminants.”

Max Green is a WBEZ news producer. Follow him @MaxRaphaelGreen.