Suffolk County, NY

ZIP 11721

In ZIP 11721, 3 of the 12 things we check have at least one part graded D or F.

• Drinking water: Suffolk County Water Authority has 2 contaminants at or over an EPA legal limit; 17 contaminants are above health goals, led by pfos at 6.2× California’s Public Health Goal.
• Nearest Superfund site: Syosset Landfill, 8.2 miles away (3 within 10 miles).
• Largest share of modeled toxic air from industry: Oerlikon Metco (US) Inc (65%), mostly chromium.
• Fine particles (PM2.5) average 6.8 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 167,580 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 11721

• Superfund sites nearbyA
• Factories and industrial sitesA to B
• Oil and gas wellsA
• Parks and nature nearbyD
• Air qualityB
• Drinking water qualityC to F
• Pesticide useC to D
• Neighborhood health statusB
• Past wildfire impactsA
• Past flood impactsC
• Noise levelsA

Based on 4 census tracts · compiled September 10, 2026 · how each grade works and its sources

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