Contaminant 8000
Unresolved Revised Total Coliform Rule violation cited in 2024 (contaminant 8000).
City · TRI 2024
Mason City, Iowa Pollution
10 TRI facilities inside the city limits and 1 public water system serving residents. In-city TRI releases more than doubled year over year (+76%). Toxic releases concentrations are up 50% since 2010.
FIPS 1950160 · population 27,271 · Cerro Gordo County
Anomaly engine
Notable Signals
Pollutant pathways
Mason City 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.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
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.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
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 are up 44% 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 have more than doubled 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 more than doubled since 2010.
Top facilities · TRI 2024
Largest Emitters Inside The City
| Facility | Top chemical | Total releases | YoY |
|---|---|---|---|
| AG Processing INCAG Processing INC | n-HexaneHealth riskPeripheral neurotoxin. Chronic exposure causes numbness and paralysis in the extremities. (ATSDR) | 122k lb | +55% |
| Curries Div Of Aadg INC.Assa Abloy INC | Certain glycol ethersHealth riskReproductive toxicants; some cause testicular damage and developmental harm. (EPA) | 80k lb | +411% |
| Kraft Heinz Foods COThe Kraft Heinz Co | 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) | 54k lb | +79% |
| Golden Grain Energy LLCGolden Grain Energy LLC | AcetaldehydeHealth riskIARC Group 2B possible carcinogen (Group 1 in connection with alcohol consumption); eye and respiratory irritant. (IARC) | 22k lb | +7% |
| Heidelberg Materials US Cement LLCHeidelberg Materials US INC | Aluminum (fume or dust)Health riskInhaled aluminum fumes can cause lung scarring (aluminosis); high cumulative exposure has been linked to neurological effects. (NIOSH) | 14k lb | -20% |
| Woodharbor Doors & Cabinetry | Xylene (mixed isomers)Health riskEye, skin, and respiratory irritant; central-nervous-system effects from chronic exposure. (EPA) | 14k lb | +14% |
| Purina Animal Nutrition LLC - Mason CityLand O Lakes INC | Zinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR) | 4k lb | — |
| Minnesota Rubber & PlasticsQuadion CORP | Zinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR) | 3k lb | +126% |
| Reg Mason City LLCChevron CORP | MethanolHealth riskAcutely toxic if ingested or inhaled. Metabolizes to formaldehyde and formic acid, causing blindness and metabolic acidosis. (EPA) | 3k lb | 0% |
| Stellar Industries INC. - Mason City PlantStellar Industries INC | LeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) | 0 lb | — |
Drinking water · SDWIS
Water Systems Serving Mason City
1 unresolved violation on the SDWIS record across utilities serving this city.
1
Utilities serving
27,338
Population served
0
Health-based · 5yr
1
Unresolved
| Water system | PWSID | Population served | Health-based · 5yr | Status |
|---|---|---|---|---|
| Mason City Water Department Municipal | IA1750048 | 27,338 | 0 | UNRESOLVED |
A public water systemis the regulated entity, not the city. EPA's SDWIS definition covers anything serving 25+ people for 60+ days a year or with 15+ service connections — that includes municipal utilities (City of Stockton), water districts, mobile home parks operating their own wells, schools, and small private subdivisions. Each system is independently monitored. Some systems serve multiple cities; some cities are served by many systems.
Superfund / NPL sites
Federal Cleanup Sites In Mason City
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 | Status | Federal facility | Primary contaminant |
|---|---|---|---|
| Mason City Coal Gasification Plant | NPL FINAL | No | Dibenzo(A,H)Anthracene |
| Lehigh Portland Cement Co. | DELETED | No | ArsenicHealth 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) |
| Northwestern States Portland Cement Co. | DELETED | No | AntimonyHealth riskInhaled antimony trioxide is an IARC Group 2B possible carcinogen; respiratory and cardiovascular effects from long-term exposure. EPA MCL 6 µg/L. (IARC, EPA) |
Equity context · ACS 2018-2022 · USEPA-clone EJ disparity
Who Lives In Mason City
Mason City, Iowa (Census place block groups): 27,271 residents. City disparity score for pm2.5 (fine particulate) sits well below the reference (15). Why we surface this →
10.5%
Low-income
12.6%
People of color
4.5%
Under age 5
22.1%
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.15below the national median
- OzoneHealth riskGround-level ozone (smog) inflames the airways. Even short exposures trigger asthma attacks and worsen chronic lung and heart disease.43near 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.62above 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.40below 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.32below 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.44near 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.84in the highest 20% nationally
- 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.89in 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.92in the highest 10% nationally
- 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.36below 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.74above 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.19below the national median
- 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.76above the national median
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 15 | well below the reference |
| Ozone | 39 | well below the reference |
| Nitrogen dioxide (NO₂) | 58 | below the reference |
| Diesel particulate | 40 | well below the reference |
| Toxic releases (RSEI) | 29 | well below the reference |
| Traffic proximity | 41 | well below the reference |
| Lead-paint risk (pre-1960 housing) | 74 | below the reference |
| Superfund site proximity | 81 | below the reference |
| RMP-facility proximity | 83 | below the reference |
| Hazardous-waste site proximity | 33 | well below the reference |
| Underground storage tanks | 60 | below the reference |
| NPDES wastewater proximity | 16 | well below the reference |
| Drinking-water non-compliance | 0 | well below the reference |
Source: Census ACS 2018-2022 (5-year) + USEPA-clone EJ blockgroup stats (raw indicators + EJ disparity mirror).
Health context
Co-Located Health Indicators
Modeled adult-prevalence estimates published by CDC PLACES, paired with this city's pollution and demographic context. Comparisons are ecological, not causal — pollution and disease prevalence covary at the area level, but the data does not attribute any individual's diagnosis to local exposure. How this section works →
Adult asthma (current)
10.3%
CDC PLACES · 2025 release · BRFSS 2022-2023
COPD prevalence
8.1%
CDC PLACES · 2025 release · BRFSS 2022-2023
Coronary heart disease
7.8%
CDC PLACES · 2025 release · BRFSS 2022-2023
Diabetes (diagnosed)
12.4%
CDC PLACES · 2025 release · BRFSS 2022-2023
Frequent mental distress
16.7%
CDC PLACES · 2025 release · BRFSS 2022-2023
PLACES uses BRFSS-modeled small-area estimates, not individual records. Crude prevalence shown above is the local rate as published; comparators are age-adjusted vs the Iowa mean and the US mean — both population-weighted across counties — so geographies with different age structures stay apples-to-apples. Sources: CDC PLACES · 2025 release · BRFSS 2022-2023.
Sources.
- EPA Toxics Release Inventory · retrieved 2026-05-07.
- EPA Safe Drinking Water Information System · retrieved 2026-05-07.