Middlesex, MA
Transparent derived index from EPA TRI / SDWIS / Superfund extracts: not an official EPA rating. Fixed caps: facilities ≤25 pts (50+ = max), log10 releases ≤25 pts, Superfund ≤25 pts (5/site), health-violation systems ≤15 pts (3/system), high-chemical facilities ≤10 pts. Bands: High ≥60, Moderate ≥30. See methodology. This is a different measure than the EJ Screening score for this county, which ranks it by percentile against other tracked counties rather than against these fixed caps.
Environmental data for Middlesex in Massachusetts · Population: 1,622,896
TRI sites such as Chemgenes Corp; Ideal Tape Co; Duncan Galvanizing Corp.; SDWIS systems such as LOWELL REGIONAL WATER UTILITY; CAMBRIDGE WATER DEPARTMENT; NEWTON WATER DEPT. (MWRA); NPL sites such as Charles-George Reclamation Trust Landfill; Fort Devens-Sudbury Training Annex; Hanscom Field/Hanscom Air Force Base anchor Middlesex, MA's EPA extract. Derived burden score 96/100 (High Risk) uses fixed national caps on density, log release volume, Superfund count, and health-flagged systems - not an official EPA rating.
EPCRA disclosures in Middlesex total 4.6M lbs; health-flagged SDWIS rows include LOWELL REGIONAL WATER UTILITY; NEWTON WATER DEPT. (MWRA); SOMERVILLE WATER DEPT. (MWRA), while Chemgenes Corp leads TRI pounds. AQS median AQI 37 / peak 93 in 2024.
Largest TRI sites in the extract: Chemgenes Corp; Ideal Tape Co; Duncan Galvanizing Corp.. Named SDWIS systems: LOWELL REGIONAL WATER UTILITY; CAMBRIDGE WATER DEPARTMENT; NEWTON WATER DEPT. (MWRA). NPL sites on record: Charles-George Reclamation Trust Landfill; Fort Devens-Sudbury Training Annex; Hanscom Field/Hanscom Air Force Base. Burden score 96/100 (High Risk) is the only weighted composite here; tables reproduce EPA disclosure history, not a current-safety verdict.
Release-over-release change
What changed for Middlesex, MA: EPA TRI 2023 reporting year
Same facilities, both years
+56.3%
69 facilities that filed in 2022 and 2023
Whole inventory
+52.8%
826.5 thousand lb → 1.3 million lb, every facility that filed
Between the two reporting years, 0 facilities filed for the first time and 6 stopped filing. Facilities entering or leaving the inventory are excluded from the same-facility comparison above.
- Middlesex, MA's total reported releases rose from 807.8 thousand lb in 2022 to 1.3 million lb in 2023, based on EPA TRI filings.
- Middlesex, MA's land releases fell from 677 lb in 2022 to 4 lb in 2023, based on EPA TRI filings.
- Middlesex, MA's off-site transfers rose from 619.1 thousand lb in 2022 to 1.1 million lb in 2023, based on EPA TRI filings.
- Middlesex, MA's water releases fell from 4.3 thousand lb in 2022 to 1.7 thousand lb in 2023, based on EPA TRI filings.
Air Quality History (2020–2024)
EPA Air Quality Index (AQI) data showing how many days per year fall into each air quality category.
| Year | Good | Moderate | Unhealthy (SG) | Max AQI |
|---|---|---|---|---|
| 2024 | 314 (86%) | 52 | 0 | 93 |
| 2023 | 281 (77%) | 83 | 1 | 101 |
| 2022 | 310 (85%) | 55 | 0 | 90 |
| 2021 | 299 (82%) | 64 | 1 | 153 |
| 2020 | 306 (84%) | 60 | 0 | 93 |
Source: EPA Air Quality System (AQS) Annual AQI by County AQI categories: Good (0-50), Moderate (51-100), Unhealthy for Sensitive Groups (101-150), Unhealthy (151-200), Very Unhealthy (201-300), Hazardous (301+)
For real-time air quality readings and pollutant breakdowns in Massachusetts, see the EPA's AirNow.gov.
Water Systems (91)
| System | System pop (SDWIS) | Violations |
|---|---|---|
| LOWELL REGIONAL WATER UTILITY | 120,418 | 7 |
| CAMBRIDGE WATER DEPARTMENT | 118,214 | 0 |
| NEWTON WATER DEPT. (MWRA) | 88,931 | 4 |
| SOMERVILLE WATER DEPT. (MWRA) | 81,045 | 7 |
| FRAMINGHAM WATER DEPT. (MWRA) | 72,362 | 3 |
| MALDEN WATER DIVISION (MWRA) | 66,263 | 7 |
| WALTHAM WATER DEPARTMENT | 65,218 | 5 |
| MEDFORD WATER DEPT. (MWRA) | 61,700 | 8 |
| EVERETT WATER DEPT. (MWRA) | 49,075 | 6 |
| ARLINGTON WATER DEPT. (MWRA) | 46,308 | 3 |
| BILLERICA WATER WORKS | 42,119 | 7 |
| MARLBOROUGH DPW WATER DIV. (MWRA) | 41,799 | 0 |
| WOBURN WATER DEPT. | 40,876 | 3 |
| NATICK WATER AND SEWER DIVISION | 37,006 | 0 |
| WATERTOWN DEPARTMENT OF PUBLIC WORKS | 35,985 | 4 |
| LEXINGTON WATER DEPT. (MWRA) | 34,074 | 4 |
| TEWKSBURY WATER DEPARTMENT | 31,342 | 4 |
| MELROSE WATER DIVISION (MWRA) | 29,938 | 9 |
| CHELMSFORD WATER DISTRICT | 28,750 | 0 |
| BELMONT WATER DEPT. (MWRA) | 27,442 | 4 |
| WAKEFIELD WATER DEPT | 27,090 | 5 |
| READING WATER DEPARTMENT (MWRA) | 26,262 | 3 |
| BURLINGTON WATER DEPT | 25,864 | 0 |
| DRACUT WATER SUPPLY DISTRICT | 25,808 | 0 |
| STONEHAM WATER DEPT (MWRA SUPPLY) | 23,244 | 7 |
| WINCHESTER WATER DEPT | 22,970 | 0 |
| WILMINGTON WATER DEPT | 21,654 | 5 |
| ACTON WATER SUPPLY DISTRICT | 21,285 | 0 |
| HUDSON WATER SUPPLY | 20,032 | 0 |
| WESTFORD WATER DEPARTMENT | 18,848 | 0 |
| ASHLAND WATER AND SEWER DEPT. | 18,832 | 2 |
| CONCORD WATER DEPT | 18,788 | 5 |
| SUDBURY WATER DISTRICT | 18,416 | 1 |
| NORTH READING WATER DEPT. | 16,379 | 13 |
| HOLLISTON WATER DEPARTMENT | 15,139 | 12 |
| BEDFORD WATER DEPT. | 14,955 | 0 |
| WAYLAND WATER DEPARTMENT | 14,096 | 1 |
| HOPKINTON WATER DEPARTMENT | 12,680 | 0 |
| HANSCOM AFB | 11,789 | 2 |
| WESTON WATER DEPT. | 11,391 | 6 |
| MAYNARD DPW, WATER DIVISION | 10,616 | 12 |
| KENWOOD WATER DISTRICT | 9,620 | 0 |
| LITTLETON WATER DEPARTMENT | 9,307 | 0 |
| PEPPERELL DPW WATER DIVISION | 9,217 | 2 |
| AYER DPW WATER DIVISION | 8,479 | 0 |
| NORTH CHELMSFORD WATER DIST | 7,660 | 0 |
| TOWNSEND WATER DEPARTMENT | 6,832 | 0 |
| LINCOLN WATER DEPT | 5,593 | 2 |
| GROTON WATER DEPARTMENT | 5,456 | 0 |
| TYNGSBOROUGH WATER DISTRICT | 4,416 | 0 |
| SHIRLEY WATER DISTRICT | 4,165 | 0 |
| EAST CHELMSFORD WATER DISTRICT | 2,800 | 0 |
| TEWKSBURY HOSPITAL | 2,500 | 0 |
| WEST GROTON WATER SUPPLY DISTRICT | 1,853 | 0 |
| APPLEWOOD COMMUNITY CORPORATION | 500 | 0 |
| PADDOCK ESTATES | 463 | 0 |
| BROOK VILLAGE CONDOMINIUM | 400 | 0 |
| CODMAN HILL CONDOMINIUM | 360 | 0 |
| HARVARD RIDGE CONDOMINIUM | 350 | 2 |
| DUNSTABLE WATER DEPARTMENT | 337 | 0 |
| JUNIPER HILL WATER COMPANY | 220 | 0 |
| BEDFORD VA HOSPITAL (ROGERS MEM. HOSP.) | 177 | 0 |
| PILOT GROVE APARTMENTS | 175 | 0 |
| SANDY BOTTOM ESTATES MHP | 168 | 0 |
| RIVER CROSSING CONDOMINIUM | 150 | 0 |
| PILOT GROVE APARTMENTS II | 134 | 0 |
| REGENCY AT STOW CONDOMINIUMS | 132 | 4 |
| WILLOWS AT BOXFORD | 132 | 0 |
| COLONY HEIGHTS CONDOMINIUM | 120 | 1 |
| CRAWFORD HILLS | 118 | 1 |
| JACK O LANTERN CONDOS | 98 | 0 |
| CURTIS HILL CONDOMINIUM | 96 | 0 |
| THE MEETING HOUSE @ STOW CONDO | 92 | 0 |
| LIBERTY HOUSE CONDOMINIUM | 80 | 1 |
| CARRIAGE HOUSE CONDOMINIUM | 68 | 0 |
| THREE RIVERS M H COMMUNITY | 63 | 16 |
| PINE HILL VILLAGE CONDOMINIUMS | 60 | 2 |
| BENCHMARK CONDOMINIUMS | 60 | 1 |
| HAYSTACK ESTATES | 60 | 0 |
| MAILLET WOODS CONDOMINIUMS | 55 | 0 |
| ELIZABETH BROOK APARTMENTS | 54 | 1 |
| WOODWARD VILLAGE | 54 | 0 |
| THE VILLAGE AT SHEPLEY HILL | 52 | 0 |
| STILL MEADOW VILLAGE CONDOMINIUMS | 50 | 0 |
| CRAFTSMAN VILLAGE CONDOMINIUMS | 40 | 0 |
| GARRISON PLACE CONDOMINIUM TRUST | 32 | 0 |
| WINTERBERRY CONDOS | 31 | 0 |
| WOODHAVEN ELDER HOUSING COMMITTEE | 30 | 0 |
| LELAND FARMS | 25 | 0 |
| EVERGREEN MOBILE HOME PARK | 25 | 0 |
| OLD LAWRENCE ROAD | 25 | 4 |
TRI Facilities (50)
Superfund Sites (15)
| Site Name | Status | HRS Score |
|---|---|---|
| Charles-George Reclamation Trust Landfill | NPL Site | 47.20 |
| Fort Devens-Sudbury Training Annex | Deleted NPL Site | 35.57 |
| Hanscom Field/Hanscom Air Force Base | NPL Site | 50.00 |
| Industri-Plex | NPL Site | 72.42 |
| Iron Horse Park | NPL Site | 42.93 |
| Materials Technology Laboratory (USARMY) | Deleted NPL Site | 48.57 |
| Natick Laboratory Army Research, Development, and Engineering Center | NPL Site | 50.00 |
| Naval Weapons Industrial Reserve Plant | NPL Site | 50.00 |
| Nuclear Metals, Inc. | NPL Site | 58.31 |
| Nyanza Chemical Waste Dump | NPL Site | 69.22 |
| Olin Chemical | NPL Site | 50.00 |
| Silresim Chemical Corp. | NPL Site | 42.72 |
| Sutton Brook Disposal Area | NPL Site | 57.12 |
| W.R. Grace & Co., Inc. (Acton Plant) | NPL Site | 59.31 |
| Wells G&H | NPL Site | 42.71 |
Cities in Middlesex (56)
Frequently Asked Questions
What is the environmental risk level in Middlesex, Massachusetts? ▼
Are there Superfund sites in Middlesex? ▼
How many toxic release facilities are in Middlesex? ▼
What is the air quality in Middlesex? ▼
Is the drinking water safe in Middlesex? ▼
What environmental agencies cover Middlesex? ▼
What does this county environmental profile show?
This county environmental profile rolls up EPA Toxics Release Inventory facility reports, Safe Drinking Water Information System public-water-system filings, and Superfund National Priorities List sites for the county boundary defined by the U.S. Census Bureau. Facility counts reflect facilities with a reporting address inside the county, not where downstream environmental effects may be observed. Population figures are from the most recent Census ACS 5-year estimate. The county detail page is updated whenever the upstream EPA programs publish revised data; see the methodology page for the documented ingest cadence and the editorial choices governing how aggregations are computed.
Read our methodology - how this data is sourced, computed, and verified.