St. Louis Public Radio Illinois has new regulations on how power plants can close coal ash ponds that contain toxic waste. Missouri officials also are addressing coal ash ponds like this one at the Meramec Energy Center in St. Louis County. Illinois now has broad regulations for how power companies may close coal ash ponds. The rules the Illinois Pollution Control Board adopted Thursday determine how to close more than 70 ash ponds across the state that contain toxic waste. “These ponds have to close, they’re not safe,” said Andrew Rehn, a civil engineer at Prairie Rivers Network, an organization that works on pollution issues in Illinois.