Ozone 8-hour 4th-highest daily max
Ozone 8-hour 4th-highest daily max in Harris County reached 0.082 ppm in 2024, 17% above the EPA NAAQS of 0.07 ppm.
County · TRI 2024
Harris County, Texas Pollution
10 top TRI facilities tracked here. PM2.5 annual mean (NAAQS 9 µg/m³ (annual)) held roughly steady year over year (-3%). PM2.5 annual mean (NAAQS 9 µg/m³ (annual)) concentrations have fallen 18% since 2010.
FIPS 48201 · population 4,726,177
Anomaly engine
Notable Signals
PM2.5 annual mean
PM2.5 annual mean in Harris County reached 10.4 µg/m³ in 2024, 15% above the EPA NAAQS of 9 µg/m³.
Top facilities mapped
Where Chemicals Are Released In Harris County
Each red dot is one of the top TRI facilities. Size reflects 2024 total releases. County boundary outlined in blue.
Pollutant pathways
Harris County 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 18% 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 23% 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 have fallen 21% since 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 13% 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) concentrations are up 38% since 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.
TRI land + off-site releases concentrations are up 98% 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 are up 43% since 2010.
Top facilities · 2024
Where The Chemical Releases Are Concentrated
| Facility | City | Top chemical | Total releases | YoY |
|---|---|---|---|---|
| Tm Deer Park Services LPTexas Molecular LP | Deer Park | MethanolHealth riskAcutely toxic if ingested or inhaled. Metabolizes to formaldehyde and formic acid, causing blindness and metabolic acidosis. (EPA) | 14.1M lb | +4% |
| Lyondell Chemical COLyondellbasell Finance Co | Channelview | MethanolHealth riskAcutely toxic if ingested or inhaled. Metabolizes to formaldehyde and formic acid, causing blindness and metabolic acidosis. (EPA) | 3.0M lb | -1% |
| Clean Harbors Deer Park LLCClean Harbors INC | La Porte | Zinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR) | 2.3M lb | +28% |
| Valero Refining - Texas L.P. Houston RefineryValero Energy CORP | Houston | 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) | 2.2M lb | +6% |
| Exxonmobil Refining & Supply Baytown Refinery (Part)Exxon Mobil CORP | Baytown | TolueneHealth riskCentral-nervous-system depressant. Chronic high exposure causes hearing loss and developmental effects. (EPA, ATSDR) | 2.0M lb | -3% |
| Exxonmobil Baytown Chemical Plant (Part)Exxon Mobil CORP | Baytown | PropyleneHealth riskSimple asphyxiant; low direct toxicity at typical exposure levels. (NIOSH) | 1.5M lb | -20% |
| Shell Chemical LPShell Petroleum INC | Deer Park | EthyleneHealth riskSimple asphyxiant at high concentrations; precursor to many polymers; low direct toxicity. (NIOSH) | 1.5M lb | +14% |
| Chevron Phillips Chemical CO LPChevron Phillips Chemical Co LLC | Baytown | EthyleneHealth riskSimple asphyxiant at high concentrations; precursor to many polymers; low direct toxicity. (NIOSH) | 1.3M lb | +15% |
| Mitsubishi Chemical La PorteMitsubishi Chemical America INC | La Porte | MethanolHealth riskAcutely toxic if ingested or inhaled. Metabolizes to formaldehyde and formic acid, causing blindness and metabolic acidosis. (EPA) | 1.2M lb | +263% |
| Lyondell Chemical CO Bayport FacilityLyondellbasell Finance Co | Pasadena | tert-Butyl alcohol | 984k lb | +47% |
Superfund / NPL sites
Federal Cleanup Sites In Harris County
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 |
|---|---|---|---|---|
| Crystal Chemical Co. | Houston | NPL FINAL | 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) |
| French, Ltd. | Crosby | NPL FINAL | No | 1,1-DichloroethaneHealth riskSuspected carcinogen (EPA C/likely); CNS depressant. Common at solvent-contaminated sites as a degradation intermediate. (EPA, ATSDR) |
| Geneva Industries/Fuhrmann Energy | Houston | NPL FINAL | No | 1,2,3,4,6,7,8,9-Octachlorodibenzo[B,E][1,4]Dioxin (Ocdd) |
| Highlands Acid Pit | Highlands | NPL FINAL | No | BenzeneHealth riskIARC Group 1 carcinogen. Long-term inhalation causes leukemia and bone-marrow disorders. (IARC, EPA) |
| Jones Road Ground Water Plume | Houston | NPL FINAL | No | Chloroethene (Vinyl Chloride)Health riskIARC Group 1 carcinogen — angiosarcoma of the liver. Final TCE/PCE biodegradation product; commonly found in groundwater plumes. EPA MCL 2 µg/L. (IARC, EPA) |
| Many Diversified Interests, Inc. | Houston | NPL FINAL | No | LeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) |
| North Cavalcade Street | Houston | NPL FINAL | No | NaphthaleneHealth riskIARC Group 2B possible carcinogen; causes hemolytic anemia, especially in infants. (IARC) |
| Patrick Bayou | Houston | NPL FINAL | No | — |
| San Jacinto River Waste Pits | Channelview | NPL FINAL | No | 2,3,7,8-Tetrachlorodibenzo-P-Dioxin (Tcdd) Toxicity Equivalents (Teq) |
| Sikes Disposal Pits | Crosby | NPL FINAL | No | (E)-1,3-Dichloro-1-Propene |
Showing the top 10 sites by status priority. 6 additional NPL-relevant sites in Harris County have entity pages — browse them via the host-county or host-city page rollups.
Equity context · ACS 2018-2022 · USEPA-clone EJ disparity
Who Lives In Harris County
All block groups in Harris County County, TX: 4,726,177 residents. County disparity score for pm2.5 (fine particulate) sits well above the reference burden (174). Why we surface this →
15.8%
Low-income
72.4%
People of color
7.2%
Under age 5
11.0%
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.87in the highest 20% nationally
- OzoneHealth riskGround-level ozone (smog) inflames the airways. Even short exposures trigger asthma attacks and worsen chronic lung and heart disease.69above 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.92in the highest 10% nationally
- 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.73above 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.99in the highest 5% nationally
- 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.72above 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.46near 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.74above 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.93in 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.71above 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.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.79above the national median
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 174 | well above the reference burden |
| Ozone | 51 | below the reference |
| Nitrogen dioxide (NO₂) | 170 | well above the reference burden |
| Diesel particulate | 139 | moderately above the reference |
| Toxic releases (RSEI) | 188 | well above the reference burden |
| Traffic proximity | 131 | moderately above the reference |
| Lead-paint risk (pre-1960 housing) | 54 | below the reference |
| Superfund site proximity | 102 | near the reference |
| RMP-facility proximity | 158 | well above the reference burden |
| Hazardous-waste site proximity | 124 | moderately above the reference |
| Underground storage tanks | 129 | moderately above the reference |
| NPDES wastewater proximity | 119 | moderately above the reference |
| Drinking-water non-compliance | 17 | 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 county'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)
9.2%
CDC PLACES · 2025 release · BRFSS 2022-2023
COPD prevalence
5.5%
CDC PLACES · 2025 release · BRFSS 2022-2023
Coronary heart disease
5.4%
CDC PLACES · 2025 release · BRFSS 2022-2023
Diabetes (diagnosed)
13.2%
CDC PLACES · 2025 release · BRFSS 2022-2023
Frequent mental distress
16.5%
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 Texas 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.
Browse
All 25 Harris County Cities With TRI Data
Pollution trends and TRI 2024 pages for every tracked city in this county. Alphabetical.
- Aldine pollution· 6 facilities
- Baytown pollution· 14 facilities
- Bellaire pollution· 0 facilities
- Channelview pollution· 6 facilities
- Crosby pollution· 1 facility
- Deer Park pollution· 13 facilities
- El Lago pollution· 0 facilities
- Galena Park pollution· 2 facilities
- Highlands pollution· 1 facility
- Houston pollution· 98 facilities
- Humble pollution· 0 facilities
- Jacinto City pollution· 1 facility
- Jersey Village pollution· 1 facility
- Katy pollution· 3 facilities
- La Porte pollution· 5 facilities
- Nassau Bay pollution· 0 facilities
- Pasadena pollution· 12 facilities
- Seabrook pollution· 0 facilities
- Sheldon pollution· 1 facility
- Shoreacres pollution· 0 facilities
- South Houston pollution· 2 facilities
- Spring pollution· 1 facility
- Tomball pollution· 0 facilities
- Webster pollution· 0 facilities
- West University Place pollution· 0 facilities
Sources.
- EPA Toxics Release Inventory · retrieved 2026-05-07.
All sources are federal public-domain datasets under 17 USC §105. We aggregate but do not relabel; the underlying observations remain attributable to EPA.