Contaminant 7000
Unresolved Phase I/II/V Synthetic Organic Chemical Rules violation cited in 2025 (contaminant 7000).
City · TRI 2024
Cheyenne, Wyoming Pollution
4 TRI facilities inside the city limits and 14 public water systems serving residents. In-city TRI releases more than halved year over year (-90%). Toxic releases concentrations have more than halved since 2010.
FIPS 5613900 · population 64,795 · Laramie County
Anomaly engine
Notable Signals
Total Trihalomethanes (TTHM)
Unresolved Total Trihalomethanes Rule violation cited in 2025 (total trihalomethanes (tthm)).
Contaminant 0400
Unresolved Lead and Copper Rule violation cited in 2023 (contaminant 0400).
Contaminant 0400
Unresolved Lead and Copper Rule violation cited in 2023 (contaminant 0400).
Showing the 4 most editorially weighted signals out of 10. Lower-severity signals fold into the chemical breakdown and history charts below.
Pollutant pathways
Cheyenne 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 27% 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 are up 15% 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 2011.
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 24% since 2011.
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) volumes here are too small to anchor a multi-year trend; YoY movement is still shown above.
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 volumes here are too small to anchor a multi-year trend; YoY movement is still shown above.
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 are up 39% since 2010.
Top facilities · TRI 2024
Largest Emitters Inside The City
| Facility | Top chemical | Total releases | YoY |
|---|---|---|---|
| Cheyenne Renewable Diesel CO LLCHf Sinclair CORP | Xylene (mixed isomers)Health riskEye, skin, and respiratory irritant; central-nervous-system effects from chronic exposure. (EPA) | 891 lb | -91% |
| Knife River CheyenneKnife River CORP | 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) | 120 lb | +20% |
| Voestalpine Railway Systems Nortrak INC.Voestalpine US Holding LLC | ManganeseHealth riskExcess inhalation can cause manganism, a Parkinson-like neurological disorder. (ATSDR) | 12 lb | -23% |
| U.S. Dod Usaf Wyoming AngUS Department Of Defense | NaphthaleneHealth riskIARC Group 2B possible carcinogen; causes hemolytic anemia, especially in infants. (IARC) | 3 lb | -82% |
Drinking water · SDWIS
Water Systems Serving Cheyenne
25 unresolved violations on the SDWIS record across utilities serving this city.
14
Utilities serving
77,707
Population served
5
Health-based · 5yr
25
Unresolved
| Water system | PWSID | Population served | Health-based · 5yr | Status |
|---|---|---|---|---|
| Restway Travel Park Private | WY5601292 | 62 | 2 | UNRESOLVED |
| Orchard Valley Water Company Private | WY5600012 | 260 | 2 | Returned to compliance |
| Carpenter W&S District Municipal | WY5601464 | 94 | 1 | Returned to compliance |
| Highland Ranch Estates Private | WY5600260 | 128 | 0 | UNRESOLVED |
| Evergreen Mobile Home Park Private | WY5600021 | 26 | 0 | UNRESOLVED |
Showing the 5 systems with recorded health-based or unresolved violations. 9 additional systems are in compliance with no recorded health-based violations in the past 5 years and are not individually tabulated.
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.
Equity context · ACS 2018-2022 · USEPA-clone EJ disparity
Who Lives In Cheyenne
Cheyenne, Wyoming (Census place block groups): 64,795 residents. City disparity score for pm2.5 (fine particulate) sits well below the reference (1). Why we surface this →
8.5%
Low-income
24.2%
People of color
5.7%
Under age 5
17.5%
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.1below the national median
- OzoneHealth riskGround-level ozone (smog) inflames the airways. Even short exposures trigger asthma attacks and worsen chronic lung and heart disease.71above 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.76above 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.70above 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.17below 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.45near 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.67above 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.85in 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.36below 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.45near 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.83in the highest 20% nationally
- 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.30below 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) | 1 | well below the reference |
| Ozone | 82 | below the reference |
| Nitrogen dioxide (NO₂) | 68 | below the reference |
| Diesel particulate | 63 | below the reference |
| Toxic releases (RSEI) | 16 | well below the reference |
| Traffic proximity | 42 | well below the reference |
| Lead-paint risk (pre-1960 housing) | 47 | well below the reference |
| Superfund site proximity | 70 | below the reference |
| RMP-facility proximity | 25 | well below the reference |
| Hazardous-waste site proximity | 42 | well below the reference |
| Underground storage tanks | 66 | below the reference |
| NPDES wastewater proximity | 29 | 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
6.6%
CDC PLACES · 2025 release · BRFSS 2022-2023
Coronary heart disease
5.9%
CDC PLACES · 2025 release · BRFSS 2022-2023
Diabetes (diagnosed)
10.6%
CDC PLACES · 2025 release · BRFSS 2022-2023
Frequent mental distress
16.2%
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 Wyoming 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.