The
Findett Corp. Superfund site, also known as Hayford Bridge Road Groundwater site, is located
within the city of St. Charles, Missouri, near the intersection of Elm Point
Road and Governor Drive. The city is located in St. Charles County. The site is
defined as the properties owned by Findett Corporation (Findett), including the
property formerly owned by Cadmus Corporation (Cadmus), and all properties
where groundwater contamination has migrated.
The
site is divided into four operable units (OU):
- OU1 addresses the soil and groundwater contamination on
the Findett property;
- OU2 addresses the soil contamination on the former
Cadmus property;
- OU3 addresses the contaminated groundwater that
migrated off OU1 and OU2; and,
- OU4 addresses the groundwater contamination from the
Ameren Huster Road Substation.
Contaminants,
including benzene, vinyl chloride, cis-1,2-Dichloroethylene (cis-1,2-DCE) and
chloroethane, were found in monitoring wells above maximum contaminant levels
(MCLs) located just north of the Findett property and migrating towards the Elm
Point Well Field, which serves as the source of drinking water for the city.
This groundwater plume was identified and addressed as OU3. The EPA
issued an OU3 Record of Decision (ROD) on September 28, 2005. Two major
components of the ROD included monitored natural attenuation (MNA) to prevent
contamination from reaching the Elm Point Wellfield and reduce the
contamination in the aquifer to achieve performance standards within an
estimated cleanup time frame between 10 and 20 years as well as a contingency plan to
require timely action if the natural attenuation processes do not achieve the
expected outcomes within 10 to 20 years.
An
OU3 Remedial Contingency Plan (RCP) was initiated in May 2024 based on vinyl
chloride detections at Monitoring Well MW-C17 and the OU3 estimated remedial
timeframe. The remedial timeframe for OU3 was dependent on reduced migration of
contaminants from the OU1 source area through the successful implementation of
the OU1 remedy by Findett and natural attenuation. As part of the RCP, the EPA
requested the Hayford Bridge Road OU3 group of Potentially Responsible Parties
(PRPs) to prepare a Contingency Plan Action Report (CPAR). Between December
2024 and April 2025, the Hayford Bridge Road OU3 Group of PRPs performed the
CPAR Investigation to evaluate site conditions and assess potential remedial
options to enhance the existing OU3 remedy and accelerate the OU3 remedial
timeframe. In August 2025, the EPA approved the Group’s CPAR recommendation to
implement two Enhanced Reductive Dechlorination (ERD) treatment walls in OU3.
In November 2025, the EPA approved an ERD Wall Remedial Design Investigation Work
Plan.
A
Time-Critical Removal Action memo was signed by the EPA for the PRPs to conduct the
ERD wall installation. Fieldwork began in June 2026. The EPA is overseeing site
activities.
