St. Charles County, MO

ZIP 63303

In ZIP 63303, 8 of the 12 things we check have at least one part graded D or F.

• Drinking water: St Charles County Pwsd 2 has 1 contaminant at or over an EPA legal limit; 17 contaminants are above health goals, led by nitrite at 15× https://pmc.ncbi.nlm.nih.gov/articles/PMC4535738/.
• Nearest Superfund site: Westlake Landfill, 6.2 miles away.
• Largest share of modeled toxic air from industry: Wood River Refinery (32%), mostly chromium compounds.
• Fine particles (PM2.5) average 8.9 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 138,436 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 63303

• Superfund sites nearbyA to D
• Factories and industrial sitesD
• Oil and gas wellsA to B
• Parks and nature nearbyD to F
• Air qualityD to F
• Drinking water qualityD
• Pesticide useD to F
• Neighborhood health statusB to D
• Past wildfire impactsA
• Past flood impactsA
• Noise levelsA to D
• Radiation signalsC

Based on 14 census tracts · compiled September 10, 2026 · how each grade works and its sources

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