St. Louis County, MN

ZIP 55803

In ZIP 55803, 6 of the 12 things we check have at least one part graded D or F.

• Drinking water: Duluth meets every EPA legal limit; 12 contaminants are above health goals, led by lead at 35× California’s Public Health Goal.
• Nearest Superfund site: Arrowhead Refinery Co., 6.3 miles away.
• Largest share of modeled toxic air from industry: Sappi Cloquet LLC (44%), mostly formaldehyde.
• Fine particles (PM2.5) average 6.4 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 4,289 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 55803

• Superfund sites nearbyA to C
• Factories and industrial sitesA to B
• Oil and gas wellsA
• Parks and nature nearbyB to F
• Air qualityA
• Drinking water qualityC to F
• Pesticide useB to D
• Neighborhood health statusB to D
• Past wildfire impactsA
• Past flood impactsA
• Noise levelsA to D
• Radiation signalsB to D

Based on 12 census tracts · compiled September 10, 2026 · how each grade works and its sources

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