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St. Charles, MO

Moderate Risk (58/100)

Transparent derived index from EPA TRI / SDWIS / Superfund extracts: not an official EPA rating. Fixed caps: facilities ≤25 pts (50+ = max), log10 releases ≤25 pts, Superfund ≤25 pts (5/site), health-violation systems ≤15 pts (3/system), high-chemical facilities ≤10 pts. Bands: High ≥60, Moderate ≥30. See methodology. This is a different measure than the EJ Screening score for this county, which ranks it by percentile against other tracked counties rather than against these fixed caps.

Environmental data for St. Charles in Missouri · Population: 409,830

TRI sites such as Ameren Missouri Sioux Energy Center; General Motors Wentzville Assembly; Superior Home Products Inc; SDWIS systems such as ST CHARLES COUNTY PWSD 2; ST CHARLES PWS; ST PETERS PWS; NPL sites such as Weldon Spring Former Army Ordnance Works; Weldon Spring Quarry/Plant/Pits (USDOE/Army) anchor St. Charles, MO's EPA extract. Derived burden score 58/100 (Moderate Risk) uses fixed national caps on density, log release volume, Superfund count, and health-flagged systems - not an official EPA rating.

EPCRA disclosures in St. Charles total 6.2M lbs; health-flagged SDWIS rows include PORTAGE DES SIOUX PWS; CLUBB VILLA SENIOR LIVING; WELDON SPRING HEIGHTS VILLAGE PWS, while Ameren Missouri Sioux Energy Center leads TRI pounds. AQS median AQI 44 / peak 129 in 2024.

Largest TRI sites in the extract: Ameren Missouri Sioux Energy Center; General Motors Wentzville Assembly; Superior Home Products Inc. Named SDWIS systems: ST CHARLES COUNTY PWSD 2; ST CHARLES PWS; ST PETERS PWS. NPL sites on record: Weldon Spring Former Army Ordnance Works; Weldon Spring Quarry/Plant/Pits (USDOE/Army). Burden score 58/100 (Moderate Risk) is the only weighted composite here; tables reproduce EPA disclosure history, not a current-safety verdict.

Release-over-release change

What changed for St. Charles, MO: EPA TRI 2023 reporting year

2022 → 2023

Same facilities, both years

-16.0%

13 facilities that filed in 2022 and 2023

Whole inventory

-16.0%

1.2 million lb → 988.2 thousand lb, every facility that filed

Between the two reporting years, 1 facility filed for the first time and 0 stopped filing. Facilities entering or leaving the inventory are excluded from the same-facility comparison above.

  • St. Charles, MO's total reported releases fell from 1.2 million lb in 2022 to 988.1 thousand lb in 2023, based on EPA TRI filings.
  • St. Charles, MO's off-site transfers fell from 13.6 thousand lb in 2022 to 8.5 thousand lb in 2023, based on EPA TRI filings.
  • St. Charles, MO's land releases fell from 650.8 thousand lb in 2022 to 544.5 thousand lb in 2023, based on EPA TRI filings.
  • St. Charles, MO's air releases fell from 511.2 thousand lb in 2022 to 434.8 thousand lb in 2023, based on EPA TRI filings.
County population (Census ACS)
409,830
TRI Facilities
16
Water Systems
22
Superfund Sites
2
Total Releases
6.2M lbs

Air Quality History (2020–2024)

EPA Air Quality Index (AQI) data showing how many days per year fall into each air quality category.

Year Good Moderate Unhealthy (SG) Max AQI
2024 191 (73%) 67 3 129
2023 156 (64%) 74 15 147
2022 206 (84%) 32 7 129
2021 209 (85%) 34 2 119
2020 216 (88%) 25 4 112
2024 Good Air Quality: 73% of days
Unhealthy days: 3
Median AQI: 44

Source: EPA Air Quality System (AQS) Annual AQI by County AQI categories: Good (0-50), Moderate (51-100), Unhealthy for Sensitive Groups (101-150), Unhealthy (151-200), Very Unhealthy (201-300), Hazardous (301+)

For real-time air quality readings and pollutant breakdowns in Missouri, see the EPA's AirNow.gov.

Water Systems (22)

System System pop (SDWIS) Violations
ST CHARLES COUNTY PWSD 2 100,587 0
ST CHARLES PWS 78,961 0
ST PETERS PWS 52,575 0
WENTZVILLE PWS 41,784 0
OFALLON PWS 32,515 0
ST CHARLES CO PWSD #2 WRIGHT CITY 3,550 0
ST PAUL PWS 1,700 0
ST CHARLES COUNTY PWSD 2 WARREN 1,192 0
ST CHARLES CO PWSD 2 AUGUSTA 881 0
ST CHARLES COUNTY PWSD 2 NORTH OAK DR 660 0
ST CHARLES PWSD 2 FORISTELL 550 0
ECM WATER & SEWER AUTHORITY - FLINT HILL 469 0
ST CHARLES COUNTY PWSD 2 DUTZOW 400 0
PORTAGE DES SIOUX PWS 345 1
PRAIRIE VIEW ACRES SUBD 135 0
CLUBB VILLA SENIOR LIVING 110 67
ST CHARLES CO PWSD 2 - SUMAC RIDGE 103 0
WELDON SPRING HEIGHTS VILLAGE PWS 100 1
TARA OAKS MANOR ASSN 100 2
BIG COUNTRY ACRES SUBDIVISION 90 0
FENNEC FOX WAY LLC 70 0
COUNTRY ESTATES 50 7

TRI Facilities (16)

# Facility Total Releases
1 Ameren Missouri Sioux Energy Center 3.9M lbs
2 General Motors Wentzville Assembly 2.1M lbs
3 Superior Home Products Inc 90.9K lbs
4 Zoltek Corp 38.2K lbs
5 O'Fallon Casting 16.1K lbs
6 Memc LLC 6.7K lbs
7 Diagraph Marking & Coding 533 lbs
8 Woodbridge Corp Saint Peters 423 lbs
9 Modineer Plant 7 105 lbs
10 True Manufacturing Co Inc 8 lbs
11 Pittsburgh Glass Works LLC 5 lbs
12 Whisk Products Inc 1 lbs
13 Newco Enterprises Inc 0 lbs
14 Weldon Spring Usarc/lta 0 lbs
15 Cmc Rebar - St. Louis 0 lbs
16 Warren County Concrete - Wentzville 0 lbs

Superfund Sites (2)

Site Name Status HRS Score
Weldon Spring Former Army Ordnance Works NPL Site 30.26
Weldon Spring Quarry/Plant/Pits (USDOE/Army) NPL Site 58.60

Cities in St. Charles (13)

Wentzville
4 facilities · 2 water
Saint Peters
4 facilities · 0 water
O Fallon
3 facilities · 2 water
Saint Charles
2 facilities · 0 water
Weldon Spring
1 facilities · 1 water
West Alton
1 facilities · 0 water
Foristell
0 facilities · 2 water
Defiance
0 facilities · 1 water
Portage Des Sioux
0 facilities · 1 water
St Charles
0 facilities · 1 water
St Paul
0 facilities · 1 water
St Peters
0 facilities · 1 water
St. Charles County
0 facilities · 0 water

Frequently Asked Questions

What is the environmental risk level in St. Charles, Missouri? ▼
St. Charles, MO has an environmental risk score of 58/100 (Moderate Risk), based on 16 TRI facilities, 2 Superfund sites, and 22 water systems on record. 5 water systems have health-based violations. Source: EPA TRI, SDWIS, and Superfund NPL.
Are there Superfund sites in St. Charles? ▼
Yes, St. Charles, MO has 2 Superfund sites on the EPA National Priorities List (NPL). Superfund sites are contaminated locations that require long-term cleanup under the EPA Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).
How many toxic release facilities are in St. Charles? ▼
St. Charles, MO has 16 TRI-reporting facilities on record with the EPA Toxic Release Inventory, with a combined total of 6.2M lbs in reported toxic releases. TRI facilities self-report annual chemical release data to the EPA.
What is the air quality in St. Charles? ▼
In 2024, St. Charles, MO recorded a median AQI of 44 and a peak AQI of 129. 73% of monitored days had "Good" air quality (AQI 0–50). Source: EPA Air Quality System (AQS) Annual AQI by County.
Is the drinking water safe in St. Charles? ▼
St. Charles, MO has 22 EPA-regulated water systems. 5 systems have reported health-based violations (MCL exceedances). A past violation does not necessarily mean water is currently unsafe. For current water quality, contact your local water utility. Source: EPA SDWIS.
What environmental agencies cover St. Charles? ▼
Environmental compliance in St. Charles, Missouri is overseen by the U.S. Environmental Protection Agency (EPA) at the federal level and the Missouri state environmental agency. Facilities report to the EPA Toxic Release Inventory, water systems are regulated under the Safe Drinking Water Act, and contaminated sites are managed under the Superfund program. Contact your state environmental agency for local concerns.

What does this county environmental profile show?

This county environmental profile rolls up EPA Toxics Release Inventory facility reports, Safe Drinking Water Information System public-water-system filings, and Superfund National Priorities List sites for the county boundary defined by the U.S. Census Bureau. Facility counts reflect facilities with a reporting address inside the county, not where downstream environmental effects may be observed. Population figures are from the most recent Census ACS 5-year estimate. The county detail page is updated whenever the upstream EPA programs publish revised data; see the methodology page for the documented ingest cadence and the editorial choices governing how aggregations are computed.

Related Guides

Understanding EPA Data
How EPA collects and publishes environmental data
Environmental Justice
Who lives near polluters and environmental hazards
How to Check Environmental Quality
Step-by-step guide to checking your local environment

Read our methodology - how this data is sourced, computed, and verified.

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Data sourced from U.S. EPA environmental datasets. See our methodology for details. Retrieved and formatted by PlainEnviro