Colorado health officials denied Xcel Energy’s initial proposal to clean up coal ash contamination at the Valmont Power Station just outside Boulder, saying it failed to meet state standards for protecting health and the environment.
Coal ash, a toxic byproduct of burning coal, has contaminated groundwater at the site and is migrating toward nearby neighborhoods, a Boulder Reporting Lab investigation found. The pollution is largely hidden underground but represents a significant and long-lasting source of contamination. After nearly a century of coal burning at Valmont, Xcel retired the facility’s last coal unit in 2017 and converted it to natural gas.
Both state and federal rules require Xcel to remove more than a million tons of coal ash and restore groundwater to safe levels. But disturbing and hauling away the buried ash could also release toxic dust into the air. Xcel says the cleanup — including groundwater treatment and ash removal — is set to begin in early 2026 and take at least a decade. The site isn’t expected to be largely restored until the mid-2030s. The project is estimated to cost $60 million to $70 million, with the state Public Utilities Commission deciding how much of that bill falls to Xcel’s Colorado customers.
The state’s preliminary decision reflects how responsibility for oversight is falling more heavily on state and local governments. Federal coal ash oversight lagged under President Biden and has further weakened under President Trump, environmental advocates say…