Ozone 8-hour 4th-highest daily max
Ozone 8-hour 4th-highest daily max in New London County reached 0.073 ppm in 2024, 4% above the EPA NAAQS of 0.07 ppm.
County · TRI 2024
New London County, Connecticut Pollution
8 top TRI facilities tracked here. PM2.5 annual mean (NAAQS 9 µg/m³ (annual)) fell meaningfully year over year (-23%). PM2.5 annual mean (NAAQS 9 µg/m³ (annual)) concentrations have more than halved since 2010.
FIPS 09011 · population 0
Anomaly engine
Notable Signals
Total TRI releases
Total TRI releases at New London County have more than three-quarters since 2010 (through 2024).
Top facilities mapped
Where Chemicals Are Released In New London County
Each red dot is one of the top TRI facilities. Size reflects 2024 total releases. County boundary outlined in blue.
Pollutant pathways
New London 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 more than halved 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 46% 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 13% 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 more than halved 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 halved 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 more than halved since 2010.
Top facilities · 2024
Where The Chemical Releases Are Concentrated
| Facility | City | Top chemical | Total releases | YoY |
|---|---|---|---|---|
| Electric Boat CorpGeneral Dynamics CORP | Groton | DiisocyanatesHealth riskLeading cause of occupational asthma; severe respiratory sensitizers. (OSHA) | 10k lb | -8% |
| Americas Styrenics Allyns Point PlantAmericas Styrenics LLC | Gales Ferry | StyreneHealth riskIARC Group 2A probable carcinogen; central-nervous-system effects from inhalation. (IARC, EPA) | 10k lb | -4% |
| Sheffield Pharmaceuticals LLC | New London | Zinc compoundsHealth riskGenerally low acute toxicity. Chronic high-dose exposure disrupts copper absorption and immune function. (ATSDR) | 2k lb | -33% |
| Pcc StructuralsBerkshire Hathaway INC | Groton | 4,4'-IsopropylidenediphenolHealth riskBisphenol A (BPA). Endocrine disruptor that mimics estrogen; regulated for use in food contact and infant products. (EPA, FDA) | 1k lb | +18% |
| Nalas Engineering Services INCNalas Engineering Services INC | Norwich | MethanolHealth riskAcutely toxic if ingested or inhaled. Metabolizes to formaldehyde and formic acid, causing blindness and metabolic acidosis. (EPA) | 476 lb | +0% |
| Doncasters INC Precision Castings New EnglandDoncasters LTD | Groton | Cobalt | 50 lb | -17% |
| US Dod-Naval Submarine Base New LondonUS Department Of Defense | Groton | LeadHealth riskNeurotoxin. Even low childhood exposure impairs cognitive development; chronic adult exposure damages kidneys and the cardiovascular system. (EPA, ATSDR) | 29 lb | -27% |
| Montville Power LLCArclight Energy Partners | Uncasville | Polycyclic aromatic compoundsHealth riskPAH class includes IARC Group 1 carcinogens (e.g., benzo[a]pyrene); long-term exposure raises cancer risk. (IARC, EPA) | 0 lb | -99% |
Superfund / NPL sites
Federal Cleanup Sites In New London 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 |
|---|---|---|---|---|
| New London Submarine Base | Conning Towers-Nautilus Park | 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) |
Equity context
County Population Characteristics
All block groups in New London County County, CT.
Demographic shares, national-percentile rankings (PM2.5, ozone, NO₂, diesel particulate, lead-paint risk, NPL/RMP/TSDF/NPDES proximity, drinking-water non-compliance), and EJ disparity scores will render here once the EJScreen-clone ingest completes for this geography. Why this section matters →
Browse
All 14 New London County Cities With TRI Data
Pollution trends and TRI 2024 pages for every tracked city in this county. Alphabetical.
- Baltic pollution· 0 facilities
- Colchester pollution· 0 facilities
- Conning Towers-Nautilus Park pollution· 1 facility
- Gales Ferry pollution· 0 facilities
- Groton pollution· 1 facility
- Jewett City pollution· 0 facilities
- Mashantucket pollution· 0 facilities
- Mystic pollution· 0 facilities
- New London pollution· 1 facility
- Niantic pollution· 0 facilities
- Noank pollution· 0 facilities
- Norwich pollution· 1 facility
- Oxoboxo River pollution· 1 facility
- Waterford 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.