Total TRI releases
Total TRI releases at Middlesex County have risen 82% since 2010 (through 2024).
County · TRI 2024
Middlesex County, Massachusetts Pollution
10 top TRI facilities tracked here. PM2.5 annual mean (NAAQS 9 µg/m³ (annual)) fell meaningfully year over year (-16%). PM2.5 annual mean (NAAQS 9 µg/m³ (annual)) concentrations have fallen 45% since 2010.
FIPS 25017 · population 1,623,109
Anomaly engine
Notable Signals
Top facilities mapped
Where Chemicals Are Released In Middlesex County
Each red dot is one of the top TRI facilities. Size reflects 2024 total releases. County boundary outlined in blue.
Pollutant pathways
Middlesex 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 45% 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 43% 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 25% 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 are roughly unchanged from 2018.
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 31% 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 fallen 21% since 2010.
Top facilities · 2024
Where The Chemical Releases Are Concentrated
| Facility | City | Top chemical | Total releases | YoY |
|---|---|---|---|---|
| Thermo Fisher ScientificThermo Fisher Scientific INC | Chelmsford | MethanolHealth riskAcutely toxic if ingested or inhaled. Metabolizes to formaldehyde and formic acid, causing blindness and metabolic acidosis. (EPA) | 431k lb | +23% |
| Thermo Fisher ScientificThermo Fisher Scientific INC | Bedford | MethanolHealth riskAcutely toxic if ingested or inhaled. Metabolizes to formaldehyde and formic acid, causing blindness and metabolic acidosis. (EPA) | 376k lb | +9668% |
| Skyworks Solutions INCSkyworks Solutions INC | Woburn | N-Methyl-2-pyrrolidoneHealth riskReproductive and developmental toxicant; absorbed through skin. (EPA) | 161k lb | -6% |
| Chemgenes CorpChemgenes CORP | Wilmington | Chloroform | 152k lb | -9% |
| Ideal Tape COAmerican Biltrite INC | Lowell | TolueneHealth riskCentral-nervous-system depressant. Chronic high exposure causes hearing loss and developmental effects. (EPA, ATSDR) | 103k lb | -11% |
| Nasoya Foods USA Llc.Pulmuone Foods USA | Ayer | 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) | 86k lb | +39% |
| Kovalus Separation Solutions INC.Separation Solutions Enterprises Ultimate Holding LP | Wilmington | N-Methyl-2-pyrrolidoneHealth riskReproductive and developmental toxicant; absorbed through skin. (EPA) | 75k lb | -9% |
| Nyacol Nanotechnologies INC | Ashland | Antimony And Antimony CompoundsHealth 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) | 72k lb | +125% |
| Duncan Galvanizing Corp. | Everett | Zinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR) | 69k lb | -24% |
| Entegris INCEntegris INC | Bedford | Di(2-ethylhexyl) phthalate | 68k lb | +1628% |
Superfund / NPL sites
Federal Cleanup Sites In Middlesex 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 |
|---|---|---|---|---|
| Charles George Reclamation Trust Landfill | Tyngsborough | NPL FINAL | No | 2-Butanone (Methyl Ethyl Ketone) |
| Fort Devens | Devens | NPL FINAL | FEDERAL | 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) |
| Hanscom Field/Hanscom Air Force Base | Bedford | NPL FINAL | FEDERAL | 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) |
| Industri-Plex | Woburn | 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) |
| Iron Horse Park | Billerica | NPL FINAL | No | 1,2-DichloroethaneHealth riskIARC Group 2B possible carcinogen; liver and kidney toxic. EPA MCL 5 µg/L. (IARC, EPA) |
| Natick Laboratory Army Research, Development, And Engineering Center | Natick | NPL FINAL | FEDERAL | ManganeseHealth riskExcess inhalation can cause manganism, a Parkinson-like neurological disorder. (ATSDR) |
| Naval Weapons Industrial Reserve Plant | Bedford | NPL FINAL | FEDERAL | 1,1,2-Trichloroethane |
| Nuclear Metals, Inc. | West Concord | NPL FINAL | No | 1,1,2,2-Tetrachloroethane |
| Nyanza Chemical Waste Dump | Ashland | NPL FINAL | No | MercuryHealth riskNeurotoxin. Methylmercury bioaccumulates up the food chain and damages the developing nervous system. (EPA, ATSDR) |
| Olin Chemical | Wilmington | NPL FINAL | No | 2,4,4-Trimethyl-1-Pentene |
Showing the top 10 sites by status priority. 6 additional NPL-relevant sites in Middlesex 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 Middlesex County
All block groups in Middlesex County County, MA: 1,623,109 residents. County disparity score for pm2.5 (fine particulate) sits well below the reference (10). Why we surface this →
7.4%
Low-income
31.7%
People of color
5.4%
Under age 5
15.7%
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.10below the national median
- OzoneHealth riskGround-level ozone (smog) inflames the airways. Even short exposures trigger asthma attacks and worsen chronic lung and heart disease.20below 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.65above 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.79above 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.97in the highest 5% nationally
- 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.79above 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.41near 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.95in the highest 10% nationally
- 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.76above 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.56near 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.91in the highest 10% nationally
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 10 | well below the reference |
| Ozone | 23 | well below the reference |
| Nitrogen dioxide (NO₂) | 66 | below the reference |
| Diesel particulate | 56 | below the reference |
| Toxic releases (RSEI) | 63 | below the reference |
| Traffic proximity | 81 | below the reference |
| Lead-paint risk (pre-1960 housing) | 63 | below the reference |
| Superfund site proximity | 53 | below the reference |
| RMP-facility proximity | 26 | well below the reference |
| Hazardous-waste site proximity | 78 | below the reference |
| Underground storage tanks | 59 | below the reference |
| NPDES wastewater proximity | 46 | well below the reference |
| Drinking-water non-compliance | 31 | 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)
11.1%
CDC PLACES · 2025 release · BRFSS 2022-2023
COPD prevalence
4.6%
CDC PLACES · 2025 release · BRFSS 2022-2023
Coronary heart disease
4.9%
CDC PLACES · 2025 release · BRFSS 2022-2023
Diabetes (diagnosed)
8.5%
CDC PLACES · 2025 release · BRFSS 2022-2023
Frequent mental distress
14.8%
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 Massachusetts 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 30 Middlesex County Cities With TRI Data
Pollution trends and TRI 2024 pages for every tracked city in this county. Alphabetical.
- Arlington pollution· 0 facilities
- Ayer pollution· 1 facility
- Belmont pollution· 1 facility
- Burlington pollution· 0 facilities
- Cambridge pollution· 0 facilities
- Devens pollution· 1 facility
- Everett pollution· 3 facilities
- Framingham pollution· 1 facility
- Groton pollution· 0 facilities
- Hopkinton pollution· 0 facilities
- Hudson pollution· 0 facilities
- Lexington pollution· 0 facilities
- Lowell pollution· 7 facilities
- Malden pollution· 2 facilities
- Marlborough pollution· 5 facilities
- Maynard pollution· 0 facilities
- Medford pollution· 0 facilities
- Melrose pollution· 0 facilities
- Newton pollution· 0 facilities
- Pepperell pollution· 0 facilities
- Reading pollution· 0 facilities
- Shirley pollution· 0 facilities
- Somerville pollution· 0 facilities
- Stoneham pollution· 0 facilities
- Townsend pollution· 0 facilities
- Wakefield pollution· 1 facility
- Waltham pollution· 2 facilities
- Wilmington pollution· 8 facilities
- Winchester pollution· 0 facilities
- Woburn pollution· 5 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.