Humboldt County, CA

ZIP 95555

In ZIP 95555, 4 of the 12 things we check have at least one part graded D or F.

• Drinking water: Moonstone Heights Mwa has 1 contaminant at or over an EPA legal limit; 10 contaminants are above health goals, led by pfos at 2.5× California’s Public Health Goal.
• Nearest Superfund site: Celtor Chemical Works, 4.4 miles away (2 within 10 miles).
• Largest share of modeled toxic air from industry: Pg&E Humboldt Bay Power Plant (100%), mostly acetaldehyde.
• Fine particles (PM2.5) average 8.3 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 15,274 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 95555

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

Based on 2 census tracts · compiled October 25, 2026 · how each grade works and its sources

Loading the full report, with every source…