Massachusetts consolidates three federal EPA datasets into one statewide environmental profile: 450 Toxics Release Inventory (TRI) facilityies reporting under EPCRA Section 313, 564 community water systems regulated under the Safe Drinking Water Act, and 41 sites on the Superfund National Priorities List.

TRI facilities in MA have cumulatively disclosed 18.3M lbs of toxic chemical releases, while SDWIS records show 1,106 total violations across the state's regulated water systems — of which 236 systems carry an active health-based violation (MCL exceedance or treatment-technique failure). Activity clusters in counties such as Middlesex, Worcester, Bristol, which account for the highest combined facility, water-system, and Superfund presence.

Every figure reflects the public regulatory record as filed with the U.S. Environmental Protection Agency and is not weighted for toxicity, geographic footprint, or population exposure. A state can rank high in any individual metric because of industrial history, naturally occurring contaminants in source water, or simply the number of reporting facilities — not because current residents face unsafe conditions. Drill into any county or water system below for the full disclosure record.