St. Charles County, MO
The federal environmental record for St. Charles County (population 416,659): what is on file, where it is, and what remains open. Sources and retrieval dates are on the methodology page.
2
Superfund NPL sites
9
federal cleanup sites
4
PFAS-detecting water systems
15
TRI facilities
13
open tank releases
Superfund NPL sites
| Site | City | Status | Listed |
|---|---|---|---|
| Weldon Spring Former Army Ordnance Works | St. Charles County | on the NPL | 02/21/1990 |
| Weldon Spring Quarry/Plant/Pits (USDOE/Army) | St. Charles County | on the NPL | 07/22/1987 |
Drinking water: PFAS testing
Public water systems serving St. Charles with at least one PFAS detection under UCMR5. The federal limit for PFOA and PFOS is 4 ng/L; EPA proposed in May 2026 to rescind the limits for the other compounds, which are shown for information.
| System | Highest results | Reading |
|---|---|---|
| ST PETERS PWS MO6010719 | PFBA: 10.6 ng/L PFPeA: 5.9 ng/L PFHxA: 5.9 ng/L | above final limit |
| OFALLON PWS MO6010588 | PFBA: 6.1 ng/L PFPeA: 3.4 ng/L | detected |
| MO AMERICAN ST LOUIS ST CHARLES COUNTIES MO6010716 | PFBA: 5.1 ng/L | detected |
| ST CHARLES COUNTY PWSD 2 MO6024530 | PFBA: 6.5 ng/L | detected |
On a system with detections? Testing and treatment options
Facilities reporting toxic releases (2024)
15 facilities in St. Charles filed TRI reports for 2024, totalling 1.1M lb released.
| Facility | City | Top chemicals | Total released |
|---|---|---|---|
| AMEREN MISSOURI SIOUX ENERGY CENTER | WEST ALTON | Barium And Barium Compounds, Ammonia | 597k lb |
| GENERAL MOTORS WENTZVILLE ASSEMBLY | WENTZVILLE | Certain glycol ethers, 1,2,4-Trimethylbenzene | 479k lb |
| SUPERIOR HOME PRODUCTS INC | WENTZVILLE | Styrene | 14k lb |
| MODINEER PLANT 7 | SAINT PETERS | Zinc compounds, Aluminum (fume or dust) | 5k lb |
| ZOLTEK CORP | SAINT PETERS | Styrene | 2k lb |
| O'FALLON CASTING | O FALLON | Ammonia, Nitric acid | 2k lb |
| MEMC LLC | SAINT PETERS | Ozone, Hydrochloric acid (acid aerosols including mists, vapors, gas, fog, and other airborne forms of any particle size) | 2k lb |
| WOODBRIDGE CORP SAINT PETERS | SAINT PETERS | Diethanolamine, Toluene diisocyanate (mixed isomers) | 414 lb |
| DIAGRAPH MARKING & CODING | SAINT CHARLES | Lead compounds | 197 lb |
| MISSOURI METALS A DIV OF SAMUEL SON & CO. (USA) INC | WENTZVILLE | Nitric acid | 11 lb |
| WARREN COUNTY CONCRETE - WENTZVILLE | WENTZVILLE | - | 0 lb |
| NEWCO ENTERPRISES INC | SAINT CHARLES | - | 0 lb |
| TRUE MANUFACTURING CO INC | O'FALLON | - | 0 lb |
| CMC REBAR - ST. LOUIS | O FALLON | - | 0 lb |
| PITTSBURGH GLASS WORKS LLC | O FALLON | Lead | 0 lb |
Underground fuel tanks
EPA's UST Finder records 445 tank facilities in St. Charles: 405 tanks in service and 934 closed. 190 fuel releases are on record, of which 13 remain open. Open releases are cleanups that have not reached "no further action".
Radon
EPA maps St. Charles as Zone 2, moderate predicted indoor radon (2 to 4 pCi/L average). Radon and air quality are covered in depth on lung.com.
The record for one specific address
County figures blur what matters: distance. The Address Environmental Report runs these same federal datasets against one address and reports every site, tank, polluter and water result around it, with distances, in about a minute.
Get the report - $39All federal cleanup sites on file
The wider Superfund enterprise inventory (SEMS) for St. Charles, including sites assessed but never listed. Presence here records that EPA had reason to look, not a finding of danger.
- FINDETT CORP.ST. CHARLES
- HAYFORD BRIDGE ROAD GROUNDWATER SITE 2ST CHARLES
- LEWIS & CLARK SAWMILLWEST ALTON
- MERCURY-JUNO DRIVEWENTZVILLE
- WELDON SPRING - EX ARMY ORDNANCE PLANTST CHARLES
- WELDON SPRING FORMER ARMY ORDNANCE WORKSST. CHARLES
- WELDON SPRING QUARRY/PLANT/PITS (USDOE/ARMY)ST. CHARLES
- WELDON SPRINGS - RAFFINATE PITSST CHARLES
- WELDON SPRINGS CHEMICAL PLANTST CHARLES