King County, WA

ZIP 98040

In ZIP 98040, 3 of the 12 things we check have at least one part graded D or F.

• Drinking water: Mercer Island City Of meets every EPA legal limit; 7 contaminants are above health goals, led by chloroform at 79× California’s Public Health Goal.
• Nearest Superfund site: Quendall Terminals, 1.2 miles away (3 within 10 miles).
• Largest share of modeled toxic air from industry: Alaskan Copper Works (48%), mostly chromium compounds.
• Fine particles (PM2.5) average 6.8 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 17,223 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 98040

• Superfund sites nearbyF
• Factories and industrial sitesD
• Oil and gas wellsC
• Parks and nature nearbyB
• Air qualityB
• Drinking water qualityC
• Pesticide useA to C
• Neighborhood health statusA
• Past wildfire impactsA
• Past flood impactsA
• Noise levelsA to D
• Radiation signalsA

Based on 6 census tracts · compiled October 25, 2026 · how each grade works and its sources

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