Los Angeles County, CA

ZIP 91304

In ZIP 91304, 8 of the 12 things we check have at least one part graded D or F.

• Drinking water: Golden State Water Company - Simi Valley meets every EPA legal limit; 18 contaminants are above health goals, led by pfos at 3.4× California’s Public Health Goal.
• Closer to Superfund sites than 0% of U.S. neighborhoods, with no listed site within 10 miles of its center.
• Largest share of modeled toxic air from industry: Torrance Refining Co LLC (32%), mostly ethylene oxide.
• Fine particles (PM2.5) average 8.8 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 2,496,015 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 91304

• Superfund sites nearbyA
• Factories and industrial sitesC to D
• Oil and gas wellsC to F
• Parks and nature nearbyB to F
• Air qualityC to F
• Drinking water qualityD to F
• Pesticide useB to F
• Neighborhood health statusB to C
• Past wildfire impactsD to F
• Past flood impactsA
• Noise levelsA to C
• Radiation signalsC to D

Based on 23 census tracts · compiled September 10, 2026 · how each grade works and its sources

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