Pollution Analyst
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State · TRI 2024

Idaho Pollution

112 TRI facilities, 774 public water systems, and 12 Superfund / NPL sites across 31 counties. Statewide TRI releases rose meaningfully year over year (+17%). Toxic releases concentrations have fallen 13% since 2010.

FIPS 16 · population 1,839,106 · 44 counties total

Top counties Top facilitiesPathwaysEquity context
PM2.5 ANNUAL MEAN (NAAQS 9 ΜG/M³ (ANNUAL)) · 2010–2024
Bar chart of annual values from 2010 to 2024, in µg/m³. Most recent year (2024): 7 µg/m³.13 µg/m³'10'12'14'16'18'20'22'247 µg/m³
Anomaly engine

Notable Signals At The State Level

NAAQS EXCEEDANCE · AIR QUALITY · NAAQS

Ozone 8-hour 4th-highest daily max

Ozone 8-hour 4th-highest daily max in Idaho statewide reached 0.070 ppm in 2024, 0% above the EPA NAAQS of 0.07 ppm.

LONG-ARC REGRESSION · LONG-ARC SHIFT

TRI water releases

TRI water releases at Idaho have more than doubled since 2010 (through 2024).

Where the burden sits

County-Level TRI Choropleth

A color-shaded map of pollution data. Darker counties report more pounds of toxic chemicals released to the EPA's Toxics Release Inventory (TRI).

Shaded by total reported releases for 2024. Counties without a published page render as “no TRI data”. Red dots mark this state's top emitters.

STYLE
TRI total releases (lbs/yr)
LOW → HIGH
Statewide pollutant pathways

Idaho Pollutant Multi-Year Trends

CRITERIA AIRSINCE 2010

PM2.5 annual mean (NAAQS 9 µg/m³ (annual))Health riskFine inhalable particles 2.5 micrometers or smaller. They travel deep into the lungs and into the bloodstream — linked to asthma, heart disease, stroke, and premature death.

6.91 µg/m³ · -6% YoY · -34% since 2010

PM2.5 annual mean (NAAQS 9 µg/m³ (annual)) concentrations have fallen 34% since 2010.

CRITERIA AIRSINCE 2010

PM2.5 24-hour 98th percentile (NAAQS 35 µg/m³ (24-hour))Health riskFine inhalable particles 2.5 micrometers or smaller. They travel deep into the lungs and into the bloodstream — linked to asthma, heart disease, stroke, and premature death.

28.55 µg/m³ · +26% YoY · -17% since 2010

PM2.5 24-hour 98th percentile (NAAQS 35 µg/m³ (24-hour)) concentrations have fallen 17% since 2010.

CRITERIA AIRSINCE 2010

Ozone 8-hour 4th-highest daily max (NAAQS 0.070 ppm (8-hour))Health riskGround-level ozone (smog) forms when vehicle and industrial emissions react in sunlight. Inflames the airways, triggers asthma attacks, and worsens heart and lung disease.

0.070 ppm · +17% YoY · +3% since 2010

Ozone 8-hour 4th-highest daily max (NAAQS 0.070 ppm (8-hour)) concentrations are roughly unchanged from 2010.

CRITERIA AIRSINCE 2010

NO₂ annual mean (NAAQS 53 ppb (annual))Health riskA tailpipe and combustion gas. Concentrates near busy roads and industrial sites; raises risk of airway inflammation, asthma, and lower respiratory infections in children.

8.0 ppb · -6% YoY · -56% since 2010

NO₂ annual mean (NAAQS 53 ppb (annual)) concentrations have more than halved since 2010.

HAZARDOUS AIR2020 VINTAGE

Lifetime cancer risk all pollutants (100 in a million (EPA elevated threshold))Health riskEPA-modeled added cancer cases per million residents from a lifetime of breathing local air toxics. EPA flags 100-in-a-million as elevated.

28.2 per million · 2020 vintage

Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.

HAZARDOUS AIR2020 VINTAGE

Formaldehyde ambient mean (0.077 µg/m³ (1-in-a-million URE))Health riskAn air toxic emitted by refineries, wood products, and combustion. EPA classifies it as a known human carcinogen — long-term inhalation raises cancer risk.

1.29 µg/m³ · 2020 vintage

Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.

HAZARDOUS AIR2020 VINTAGE

Benzene ambient mean (0.13 µg/m³ (1-in-a-million URE))Health riskAn air toxic from gasoline, refineries, and tobacco smoke. A known human carcinogen — chronic exposure is linked to leukemia and other blood cancers.

0.23 µg/m³ · 2020 vintage

Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.

TRI AIRSINCE 2010

TRI air releases (5.1 fugitive + 5.2 stack)Health riskToxic chemicals reported by industrial facilities as released into the air — fugitive leaks plus smokestack emissions. Higher pounds means more inhaled exposure for nearby residents.

5.2M lb · +6% YoY · +39% since 2010

TRI air releases (5.1 fugitive + 5.2 stack) concentrations are up 39% since 2010.

TRI WATERSINCE 2010

TRI water releases (5.3)Health riskToxic chemicals reported by industrial facilities as discharged to surface waters (rivers, lakes, the ocean). Affects fishing, recreation, and downstream drinking-water intakes.

5.7M lb · +14% YoY · +130% since 2010

TRI water releases (5.3) concentrations have more than doubled since 2010.

TRI LANDSINCE 2010

TRI land + off-site releasesHealth riskToxic chemicals released to land on-site or transferred off-site for disposal — landfills, deep-well injection, and similar. Risks groundwater contamination over time.

39.9M lb · +19% YoY · -24% since 2010

TRI land + off-site releases concentrations have fallen 24% since 2010.

GHGSINCE 2010

Greenhouse gases (GHGRP large emitters, through 2023)Health riskGreenhouse gases reported by large industrial emitters under EPA's GHGRP, in metric tons of CO₂ equivalent. Drives climate warming and the heat-related health effects that follow.

12M metric tons CO₂e · +4% YoY · +55% since 2010

Greenhouse gases (GHGRP large emitters, through 2023) concentrations are up 55% since 2010.

Top counties · TRI 2024

Idaho Counties With Most Chemical Releases

Methodology →

CountyPopulationFacilitiesTotal releasesYoYTop chemical
Shoshone CountyFIPS 1607913,399524.2M lb+26%Manganese And Manganese CompoundsHealth riskExcess inhalation can cause manganism, a Parkinson-like neurological disorder. (ATSDR)
Cassia CountyFIPS 1603124,85935.6M lb+13%Nitrate compounds (water dissociable; reportable only when in aqueous solution)Health riskDrinking-water nitrate causes methemoglobinemia ('blue-baby syndrome') in infants; EPA MCL is 10 mg/L as N. (EPA)
Caribou CountyFIPS 160297,05825.1M lb+9%Zinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR)
Owyhee CountyFIPS 1607312,04333.7M lb-3%Zinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR)
Power CountyFIPS 160777,91823.1M lb+1%Vanadium compoundsHealth riskRespiratory irritant. Chronic high exposure causes 'green tongue' and bronchitis. (NIOSH)
Minidoka CountyFIPS 1606721,62632.3M lb+14%AmmoniaHealth riskSevere respiratory and eye irritant; high concentrations cause chemical burns to lung tissue. (EPA)
Nez Perce CountyFIPS 1606942,200111.5M lb-6%MethanolHealth riskAcutely toxic if ingested or inhaled. Metabolizes to formaldehyde and formic acid, causing blindness and metabolic acidosis. (EPA)
Canyon CountyFIPS 16027235,006191.2M lb+23%AmmoniaHealth riskSevere respiratory and eye irritant; high concentrations cause chemical burns to lung tissue. (EPA)
Gooding CountyFIPS 1604715,52011.1M lb-3%Nitrate compounds (water dissociable; reportable only when in aqueous solution)Health riskDrinking-water nitrate causes methemoglobinemia ('blue-baby syndrome') in infants; EPA MCL is 10 mg/L as N. (EPA)
Custer CountyFIPS 160374,34411.0M lb+496%Nitrate compounds (water dissociable; reportable only when in aqueous solution)Health riskDrinking-water nitrate causes methemoglobinemia ('blue-baby syndrome') in infants; EPA MCL is 10 mg/L as N. (EPA)
Top facilities · TRI 2024

The Largest Individual Emitters In Idaho

Methodology →

FacilityCityTop chemicalTotal releasesYoY
Hecla LTD Lucky Friday Mine UnitHecla Mining CoMullanManganese And Manganese CompoundsHealth riskExcess inhalation can cause manganism, a Parkinson-like neurological disorder. (ATSDR)19.6M lb+29%
Mccain Foods USA INC.Mccain Foods USA INCBurleyNitrate compounds (water dissociable; reportable only when in aqueous solution)Health riskDrinking-water nitrate causes methemoglobinemia ('blue-baby syndrome') in infants; EPA MCL is 10 mg/L as N. (EPA)5.6M lb+14%
P4 Production LLCBayer US Holding LPSoda SpringsZinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR)4.4M lb+11%
U.S. Silver - Idaho INCAmericas Gold And Silver CORPWallaceManganese And Manganese CompoundsHealth riskExcess inhalation can cause manganism, a Parkinson-like neurological disorder. (ATSDR)4.0M lb+18%
US Ecology Idaho INC.Republic Services INCGrand ViewZinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR)3.7M lb-3%
J R Simplot CO Don Sid IngJ R Simplot CoPocatelloVanadium compoundsHealth riskRespiratory irritant. Chronic high exposure causes 'green tongue' and bronchitis. (NIOSH)3.0M lb+1%
Amalgamated Sugar COAmalgamated Sugar CoPaulAmmoniaHealth riskSevere respiratory and eye irritant; high concentrations cause chemical burns to lung tissue. (EPA)2.3M lb+14%
Glanbia Foods INCGlanbia INCGoodingNitrate compounds (water dissociable; reportable only when in aqueous solution)Health riskDrinking-water nitrate causes methemoglobinemia ('blue-baby syndrome') in infants; EPA MCL is 10 mg/L as N. (EPA)1.1M lb-3%
Thompson Creek Mining COThompson Creek Metals CoClaytonNitrate compounds (water dissociable; reportable only when in aqueous solution)Health riskDrinking-water nitrate causes methemoglobinemia ('blue-baby syndrome') in infants; EPA MCL is 10 mg/L as N. (EPA)1.0M lb+496%
Clearwater Paper Corp-Ppd & Cpd IdahoClearwater Paper CORPLewistonMethanolHealth riskAcutely toxic if ingested or inhaled. Metabolizes to formaldehyde and formic acid, causing blindness and metabolic acidosis. (EPA)898k lb-4%
Water utilities to watch

Largest Water Systems With Unresolved Health-Based Violations

Sorted to surface utilities serving the most people that still have an active health-based SDWIS violation on the record. Systems in compliance with no unresolved issues fall to the bottom of the ranking.

Methodology →

Water systemPWSIDPopulation servedHealth-based · 5yrStatus
Meridian Water Dept PrivateID4010097147,3401UNRESOLVED
Pocatello City Of MunicipalID603004358,2313UNRESOLVED
Falls Water Company Inc PrivateID710003022,6506UNRESOLVED
Mountain Home, City Of MunicipalID420003214,6513UNRESOLVED
Blackfoot City Of MunicipalID606000713,2247UNRESOLVED
Sandpoint Public Works Dept MunicipalID109012112,2844UNRESOLVED
Burley Water Dept PrivateID516000810,3456UNRESOLVED
Capitol Water Corp PrivateID40100229,0007UNRESOLVED
Mountain Home Air Force Base FederalID42000547,5007UNRESOLVED
Fruitland City Of MunicipalID33800057,13531UNRESOLVED
Superfund / NPL sites

Federal Cleanup Sites In Idaho

Sites on EPA's Superfund National Priorities List, plus deleted sites whose cleanup objectives EPA has finalized. Federal-facility sites (defense, DOE, etc.) are flagged separately. Each link routes to a per-site page.

Methodology →

SiteCityStatusFederal facilityPrimary contaminant
Bunker Hill Mining & Metallurgical ComplexKelloggNPL FINALNoLeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR)
Eastern Michaud Flats ContaminationPocatelloNPL FINALNoArsenicHealth riskIARC Group 1 carcinogen via inhalation and ingestion. EPA MCL 10 µg/L; chronic exposure causes skin, lung, bladder cancer and cardiovascular disease. (IARC, EPA, ATSDR)
Idaho National Engineering Laboratory (Usdoe)Idaho FallsNPL FINALFEDERALLeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR)
Kerr-Mcgee Chemical Corp. (Soda Springs Plant)Soda SpringsNPL FINALNoArsenicHealth riskIARC Group 1 carcinogen via inhalation and ingestion. EPA MCL 10 µg/L; chronic exposure causes skin, lung, bladder cancer and cardiovascular disease. (IARC, EPA, ATSDR)
Monsanto Chemical Co. (Soda Springs Plant)Soda SpringsNPL FINALNoArsenicHealth riskIARC Group 1 carcinogen via inhalation and ingestion. EPA MCL 10 µg/L; chronic exposure causes skin, lung, bladder cancer and cardiovascular disease. (IARC, EPA, ATSDR)
Mountain Home Air Force BaseMountain Home AFBNPL FINALFEDERALBenzeneHealth riskIARC Group 1 carcinogen. Long-term inhalation causes leukemia and bone-marrow disorders. (IARC, EPA)
Blackbird MineLemhi CountyPROPOSEDNoArsenicHealth riskIARC Group 1 carcinogen via inhalation and ingestion. EPA MCL 10 µg/L; chronic exposure causes skin, lung, bladder cancer and cardiovascular disease. (IARC, EPA, ATSDR)
St. Maries CreosoteSt. MariesPROPOSEDNoBenzeneHealth riskIARC Group 1 carcinogen. Long-term inhalation causes leukemia and bone-marrow disorders. (IARC, EPA)
Stibnite/Yellow Pine Mining AreaStibnitePROPOSEDNo—
Arrcom (Drexler Enterprises)RathdrumDELETEDNo1,1,2,2-Tetrachloroethane

Showing the top 10 sites by status priority. 2 additional NPL-relevant sites in Idaho have entity pages — browse them via the host-county or host-city page rollups.

Equity context · ACS 2018-2022 · USEPA-clone EJ disparity

Statewide Population Characteristics

All Idaho block groups: 1,839,106 residents. Statewide disparity score for pm2.5 (fine particulate) sits below the reference (55). Why we surface this →

State-level percentiles are aggregated from block-group EJScreen data. The EJ pattern within the state will be sharper at the county level — drill down for the meaningful spatial detail.

POPULATION SHARE
11.0%

Low-income

POPULATION SHARE
19.9%

People of color

POPULATION SHARE
6.8%

Under age 5

POPULATION SHARE
16.3%

Over age 64

NATIONAL PERCENTILE · vs all US block groups (population-weighted; ranked against the national EJScreen indicator distribution)

Methodology →

  • PM2.5 (fine particulate)Health riskFine inhalable particles 2.5 micrometers or smaller. They travel deep into the lungs and into the bloodstream — linked to asthma, heart disease, stroke, and premature death.65above the national median
  • OzoneHealth riskGround-level ozone (smog) inflames the airways. Even short exposures trigger asthma attacks and worsen chronic lung and heart disease.41near the national median
  • Nitrogen dioxide (NO₂)Health riskA tailpipe and combustion gas. Concentrates near busy roads and industrial sites; raises risk of airway inflammation, asthma, and lower respiratory infections in children.46near the national median
  • Diesel particulateHealth riskSoot from diesel engines (trucks, trains, ports, construction). EPA classifies it as a likely human carcinogen and a major driver of childhood asthma near freight corridors.43near the national median
  • Toxic releases (RSEI)Health riskEPA's Risk-Screening Environmental Indicators score — weights TRI chemical releases by toxicity, where they go, and how many people are nearby. Higher means greater modeled cancer and chronic-health risk.36below the national median
  • Traffic proximityHealth riskPopulation-weighted distance to high-volume roads. Living close to heavy traffic raises exposure to PM2.5, NO₂, and diesel exhaust — and the cardiovascular and asthma risks that follow.42near the national median
  • Lead-paint risk (pre-1960 housing)Health riskShare of housing built before 1960, when lead-based paint was common. Dust from deteriorating paint is the leading cause of childhood lead poisoning, which permanently impairs cognitive development.52near the national median
  • Superfund site proximityHealth riskPopulation-weighted distance to NPL Superfund sites — the most contaminated waste sites in the country. Nearby groundwater, soil, and air can carry industrial solvents, metals, and other long-lived contaminants.69above the national median
  • RMP-facility proximityHealth riskDistance to facilities holding chemicals at quantities large enough to require an EPA Risk Management Plan (refineries, fertilizer plants, etc.). These pose acute exposure risk during accidental releases.46near the national median
  • Hazardous-waste site proximityHealth riskDistance to RCRA hazardous-waste handlers (treatment, storage, disposal facilities). Indicates potential exposure to industrial chemicals in air, soil, and groundwater.25below the national median
  • Underground storage tanksHealth riskDensity of underground tanks (gasoline, heating oil, industrial fluids). Leaking tanks are a leading source of benzene and other volatile organic compounds in groundwater drinking-water supplies.59near the national median
  • NPDES wastewater proximityHealth riskDistance to permitted industrial wastewater dischargers. Closer proximity raises exposure to pollutants released into surface waters used for fishing, recreation, and downstream drinking-water intakes.92in the highest 10% nationally
  • Drinking-water non-complianceHealth riskEPA score for public water systems with health-based Safe Drinking Water Act violations. Higher means more residents on systems that recently exceeded safe limits for contaminants like lead, arsenic, or nitrate.99in the highest 5% nationally
EJ disparity scores · population-weighted, all state block groups (100 = national reference; higher = greater disparate burden) · Methodology →
IndicatorDisparity scoreReading
PM2.5 (fine particulate)55below the reference
Ozone76below the reference
Nitrogen dioxide (NO₂)51below the reference
Diesel particulate43well below the reference
Toxic releases (RSEI)18well below the reference
Traffic proximity37well below the reference
Lead-paint risk (pre-1960 housing)40well below the reference
Superfund site proximity11well below the reference
RMP-facility proximity30well below the reference
Hazardous-waste site proximity19well below the reference
Underground storage tanks48well below the reference
NPDES wastewater proximity48well below the reference
Drinking-water non-compliance61below the reference

Source: Census ACS 2018-2022 (5-year) + USEPA-clone EJ blockgroup stats (raw indicators + EJ disparity mirror). EJ disparity scores via the USEPA-clone GitHub mirror after EPA deprecated the public EJScreen tool in 2025; demographics from Census ACS.

Browse

All 31 Idaho Counties With TRI Data

Pollution trends and TRI 2024 pages for every tracked county. Alphabetical.

Sources.