ST. CHARLES, Mo. – After months of complaints and accusations from St. Charles officials, the Environmental Protection Agency has confirmed an Ameren Missouri substation is the source of contamination at the city’s Elm Point Wellfield.
Last October, St. Charles Mayor Dan Borgmeyer said the majority of the city’s water wells had been shut down due to contamination of hazardous chemicals. By December, the city had down five of its seven wells.
Ameren’s Huster Road Substation, located near the Elm Point Wellfield, has been leaking carcinogens into the soil and groundwater, Mayor Borgmeyer said.
In the 1970s, Ameren Missouri used a scouring solvent called tetrachloroethylene to clean equipment at the substation, according to Paul Michalski, a senior hydrogeologist for 212 Environmental. Ameren attempted to degrade the chemical in soil and groundwater. Two carcinogens were created in the process—cis-1,2-Dichloroethene and vinyl chloride—both of which are harmful to human beings.
Ameren claimed at the time, “cleanup of the Huster substation has been successful in reducing on-site, and off-site impact from a cleaning produce last used decades ago.”
In January 2023, the EPA collected both ground and water samples from the Elm Point Wellfield. Lab results confirmed the presence of both of cis-1,2-Dichloroethene and vinyl chloride and identified the Ameren substation as the source.
The EPA will present additional information on its sampling and testing results at an upcoming meeting on Feb. 23 at 6 p.m. at the St. Charles Borromeo Catholic Parish gymnasium.
Ameren Missouri released a statement Wednesday afternoon saying it is implementing “EPA-approved measures to contain and remove” the hazardous chemicals. Those techniques include injecting materials into the ground to destroy the solvents, as well as installing subsurface barriers at strategic locations around the substation.
An Ameren Missouri spokesman said their work is being monitored by the EPA, and they expect to see a reduction in the concentration of these hazardous chemicals by early summer.
The St. Charles Wellhead District is the primary source of drinking water for the city. At one point, the district was able to produce six million gallons of water per day for St. Charles. As of December 2022, production was reduced to 1.5 million gallons.
While the water being pumped from the remaining wells is still safe to drink, Borgmeyer said the city has had to purchase additional water from St. Louis over the past five years.