Lewis and Clark County, MT

ZIP 59640

In ZIP 59640, 3 of the 12 things we check have at least one part graded D or F.

• Drinking water: Bridge Creek Estates Subdivision meets every EPA legal limit; 3 contaminants are above health goals, led by lead at 18× California’s Public Health Goal.
• Closer to Superfund sites than 53% of U.S. neighborhoods, with no listed site within 10 miles of its center.
• Largest share of modeled toxic air from industry: American Chemet Corp (89%), mostly copper compounds.
• Fine particles (PM2.5) average 5.7 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 26,812 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 59640

• Superfund sites nearbyC
• Factories and industrial sitesA
• Oil and gas wellsA
• Parks and nature nearbyC
• Air qualityA
• Drinking water qualityD
• Pesticide useD
• Neighborhood health statusB
• Past wildfire impactsA
• Past flood impactsA
• Noise levelsA
• Radiation signalsD

Based on 1 census tract · compiled September 10, 2026 · how each grade works and its sources

Loading the full report, with every source…