Ozone 8-hour 4th-highest daily max
Ozone 8-hour 4th-highest daily max in Arizona statewide reached 0.073 ppm in 2024, 4% above the EPA NAAQS of 0.07 ppm.
State · TRI 2024
Arizona Pollution
244 TRI facilities, 954 public water systems, and 13 Superfund / NPL sites across 14 counties. Statewide TRI releases rose modestly year over year (+11%). Toxic releases concentrations are up 47% since 2010.
FIPS 04 · population 7,151,502 · 15 counties total
Anomaly engine
Notable Signals At The State Level
TRI land + off-site releases
TRI land + off-site releases at Arizona have risen 50% 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.
Statewide pollutant pathways
Arizona Pollutant Multi-Year Trends
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.
PM2.5 annual mean (NAAQS 9 µg/m³ (annual)) concentrations have fallen 19% since 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.
PM2.5 24-hour 98th percentile (NAAQS 35 µg/m³ (24-hour)) concentrations have fallen 22% since 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.
Ozone 8-hour 4th-highest daily max (NAAQS 0.070 ppm (8-hour)) concentrations are roughly unchanged from 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.
NO₂ annual mean (NAAQS 53 ppb (annual)) concentrations have fallen 42% since 2010.
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.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
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.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
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.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
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.
TRI air releases (5.1 fugitive + 5.2 stack) concentrations have fallen 46% since 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.
TRI water releases (5.3) volumes here are too small to anchor a multi-year trend; YoY movement is still shown above.
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.
TRI land + off-site releases concentrations are up 50% since 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.
Greenhouse gases (GHGRP large emitters, through 2023) concentrations have fallen 28% since 2010.
| County | Population | Facilities | Total releases | YoY | Top chemical |
|---|---|---|---|---|---|
| Gila CountyFIPS 04007 | 53,419 | 5 | 96.2M lb | +13% | Zinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR) |
| Greenlee CountyFIPS 04011 | 9,483 | 1 | 6.3M lb | +54% | Zinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR) |
| Pima CountyFIPS 04019 | 1,042,393 | 22 | 3.9M lb | -20% | Lead And Lead CompoundsHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) |
| Yavapai CountyFIPS 04025 | 237,830 | 8 | 3.0M lb | -23% | Lead And Lead CompoundsHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) |
| Apache CountyFIPS 04001 | 66,054 | 2 | 2.5M lb | -12% | Barium compounds (except for barium sulfate (CAS No. 7727-43-7))Health riskSoluble barium compounds are toxic if ingested, affecting the heart, kidneys, and nervous system. Insoluble forms (e.g. barium sulfate) are far less toxic. (EPA) |
| Graham CountyFIPS 04009 | 38,453 | 1 | 2.3M lb | +44% | Lead And Lead CompoundsHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) |
| Maricopa CountyFIPS 04013 | 4,430,871 | 149 | 1.7M lb | +12% | Aluminum (fume or dust)Health riskInhaled aluminum fumes can cause lung scarring (aluminosis); high cumulative exposure has been linked to neurological effects. (NIOSH) |
| Pinal CountyFIPS 04021 | 433,338 | 30 | 1.3M lb | -26% | Lead compoundsHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) |
| Coconino CountyFIPS 04005 | 144,705 | 5 | 112k lb | +511% | PropyleneHealth riskSimple asphyxiant; low direct toxicity at typical exposure levels. (NIOSH) |
| Yuma CountyFIPS 04027 | 204,374 | 6 | 79k lb | +58% | CopperHealth riskInhaled copper fumes cause metal-fume fever; chronic ingestion above EPA's 1.3 mg/L action level damages the liver. (EPA) |
| Facility | City | Top chemical | Total releases | YoY |
|---|---|---|---|---|
| Asarco LLC Ray Complex/ Hayden Smelter & ConcentratorAmericas Mining CORP | Hayden | Zinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR) | 55.0M lb | +11% |
| Freeport-Mcmoran Miami INCFreeport-Mcmoran INC | Claypool | Copper And Copper CompoundsHealth riskInhaled copper fumes cause metal-fume fever; chronic ingestion above EPA's 1.3 mg/L action level damages the liver. (EPA) | 27.0M lb | +4% |
| Pinto Valley Mine | Miami | Copper And Copper CompoundsHealth riskInhaled copper fumes cause metal-fume fever; chronic ingestion above EPA's 1.3 mg/L action level damages the liver. (EPA) | 14.2M lb | +49% |
| Freeport-Mcmoran Morenci INCFreeport-Mcmoran INC | Morenci | Zinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR) | 6.3M lb | +54% |
| Freeport-Mcmoran Bagdad INCFreeport-Mcmoran INC | Bagdad | Lead And Lead CompoundsHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) | 3.0M lb | -24% |
| Freeport-Mcmoran Safford INCFreeport-Mcmoran INC | Safford | Lead And Lead CompoundsHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) | 2.3M lb | +44% |
| Springerville Generating StationUns Energy CORP | Springerville | Barium compounds (except for barium sulfate (CAS No. 7727-43-7))Health riskSoluble barium compounds are toxic if ingested, affecting the heart, kidneys, and nervous system. Insoluble forms (e.g. barium sulfate) are far less toxic. (EPA) | 2.2M lb | -9% |
| Asarco LLC Mission ComplexAmericas Mining CORP | Sahuarita | Lead And Lead CompoundsHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) | 2.1M lb | -6% |
| Freeport-Mcmoran Sierrita INCFreeport-Mcmoran INC | Green Valley | Lead And Lead CompoundsHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) | 1.7M lb | -32% |
| Asarco LLC Ray Mine OperationsAmericas Mining CORP | Kearny | Lead compoundsHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) | 1.0M lb | -29% |
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.
| Water system | PWSID | Population served | Health-based · 5yr | Status |
|---|---|---|---|---|
| Phoenix City Of Municipal | AZ0407025 | 1,695,000 | 2 | UNRESOLVED |
| Epcor - Agua Fria Private | AZ0407695 | 127,718 | 3 | UNRESOLVED |
| City Of Yuma Municipal | AZ0414024 | 103,264 | 46 | UNRESOLVED |
| Gw Santa Cruz Water Co Private | AZ0411131 | 84,000 | 2 | UNRESOLVED |
| Liberty Water Lpsco Private | AZ0407046 | 55,810 | 2 | UNRESOLVED |
| Prescott City Of Municipal | AZ0413045 | 42,217 | 1 | UNRESOLVED |
| Bullhead City Mohave Private | AZ0408032 | 36,330 | 3 | UNRESOLVED |
| Nogales City Of Municipal | AZ0412004 | 22,000 | 3 | UNRESOLVED |
| Safford City Of Municipal | AZ0405005 | 20,600 | 1 | UNRESOLVED |
| Pima Utilities Private | AZ0407120 | 20,000 | 4 | UNRESOLVED |
Superfund / NPL sites
Federal Cleanup Sites In Arizona
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.
| Site | City | Status | Federal facility | Primary contaminant |
|---|---|---|---|---|
| Apache Powder Co. | Saint David | NPL FINAL | No | NitrateHealth riskDrinking-water nitrate causes methemoglobinemia ('blue-baby syndrome') in infants; EPA MCL is 10 mg/L as N. (EPA) |
| Hassayampa Landfill | Arlington | NPL FINAL | No | 1,1,1-TrichloroethaneHealth riskMethyl chloroform. CNS depressant; ozone-depleting substance phased out under Montreal Protocol. EPA MCL 200 µg/L. (EPA, ATSDR) |
| Indian Bend Wash Area | Scottsdale | NPL FINAL | No | TetrachloroetheneHealth riskPCE / 'perc'. IARC Group 2A probable carcinogen; central-nervous-system effects; common dry-cleaning solvent and DNAPL plume contaminant. EPA MCL 5 µg/L. (IARC, EPA) |
| Iron King Mine - Humboldt Smelter | Dewey-Humboldt | NPL FINAL | No | AluminumHealth riskInhaled aluminum fumes can cause lung scarring (aluminosis); high cumulative exposure has been linked to neurological effects. (NIOSH) |
| Lukachukai Mountains Mining District | Cove | NPL FINAL | No | — |
| Motorola, Inc. (52Nd Street Plant) | Phoenix | NPL FINAL | No | 1,1,1-TrichloroethaneHealth riskMethyl chloroform. CNS depressant; ozone-depleting substance phased out under Montreal Protocol. EPA MCL 200 µg/L. (EPA, ATSDR) |
| Phoenix-Goodyear Airport Area | Goodyear | NPL FINAL | No | 2-Butanone (Methyl Ethyl Ketone) |
| Tucson International Airport Area | Tucson | NPL FINAL | No | 1,1-DichloroetheneHealth riskVinylidene chloride; IARC Group 3 (inadequate evidence in humans) but liver toxic in animal studies; common TCE/PCE biodegradation product. (IARC, EPA) |
| Williams Air Force Base | Mesa | NPL FINAL | FEDERAL | BenzeneHealth riskIARC Group 1 carcinogen. Long-term inhalation causes leukemia and bone-marrow disorders. (IARC, EPA) |
| Yuma Marine Corps Air Station | Yuma | NPL FINAL | FEDERAL | 1,1-DichloroetheneHealth riskVinylidene chloride; IARC Group 3 (inadequate evidence in humans) but liver toxic in animal studies; common TCE/PCE biodegradation product. (IARC, EPA) |
Showing the top 10 sites by status priority. 3 additional NPL-relevant sites in Arizona 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 Arizona block groups: 7,151,502 residents. Statewide disparity score for pm2.5 (fine particulate) sits below the reference (63). 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.
13.1%
Low-income
47.0%
People of color
6.1%
Under age 5
18.1%
Over age 64
- 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.29below the national median
- OzoneHealth riskGround-level ozone (smog) inflames the airways. Even short exposures trigger asthma attacks and worsen chronic lung and heart disease.88in the highest 20% nationally
- 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.70above 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.68above 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.76above 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.71above 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.38below 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.81in the highest 20% nationally
- 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.68above 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.54near 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.61above 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.94in 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.86in the highest 20% nationally
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 63 | below the reference |
| Ozone | 136 | moderately above the reference |
| Nitrogen dioxide (NO₂) | 99 | near the reference |
| Diesel particulate | 91 | near the reference |
| Toxic releases (RSEI) | 70 | below the reference |
| Traffic proximity | 89 | below the reference |
| Lead-paint risk (pre-1960 housing) | 35 | well below the reference |
| Superfund site proximity | 49 | well below the reference |
| RMP-facility proximity | 71 | below the reference |
| Hazardous-waste site proximity | 62 | below the reference |
| Underground storage tanks | 65 | below the reference |
| NPDES wastewater proximity | 95 | near the reference |
| Drinking-water non-compliance | 43 | well below 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 14 Arizona Counties With TRI Data
Pollution trends and TRI 2024 pages for every tracked county. Alphabetical.
- Apache County pollution· 2 facilities
- Cochise County pollution· 4 facilities
- Coconino County pollution· 5 facilities
- Gila County pollution· 5 facilities
- Graham County pollution· 1 facility
- Greenlee County pollution· 1 facility
- Maricopa County pollution· 149 facilities
- Mohave County pollution· 8 facilities
- Navajo County pollution· 1 facility
- Pima County pollution· 22 facilities
- Pinal County pollution· 30 facilities
- Santa Cruz County pollution· 2 facilities
- Yavapai County pollution· 8 facilities
- Yuma County pollution· 6 facilities
Sources.
- EPA Toxics Release Inventory · retrieved 2026-05-07.