Clean Water Act discharge permit · NPDES CT0003131
TRINSEO LLC, Ledyard, CT: NPDES CT0003131 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 86Pollutants under a numeric limit
- 11Pollutants with an effluent exceedance
TRINSEO LLC, held by DOW CHEMICAL USA ALLYNS POINT, holds NPDES permit CT0003131, which discharges to Thames River / Allyns Cove Pond. EPA’s file records it issued September 29, 2000 and expiring September 28, 2005. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 15, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | TRINSEO LLC |
|---|---|
| Permittee as filed | DOW CHEMICAL USA ALLYNS POINT |
| NPDES ID | CT0003131 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Individual permit |
| Discharger class | Major discharger |
| Facility type | Not a publicly owned treatment works |
| Issued | September 29, 2000 |
| Expiration date | September 28, 2005 |
| Issuing agency | CT DEP |
| Address | Ledyard, CT 06335 |
| Receiving water | THAMES RIVER / ALLYNS COVE POND |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Thames River-Frontal New London Harbor (HUC 011000030203) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 101Pollutants on file
- 86Under a numeric limit
- 91With a violation of any kind
- 11With an effluent exceedance
An effluent exceedance is a discharge monitoring report value over the permit’s numeric limit (EPA’s violation code E90). A violation of any kind also counts a report not filed. Each row is EPA’s own count for that pollutant; the 60 with the most exceedances of 101 are shown.
| Pollutant or measure | Limits | Violations, any kind | Effluent exceedances | Latest exceedance | Largest exceedance, as filed |
|---|---|---|---|---|---|
| Coliform, fecal general | 2 | 17 | 11 | September 30, 2013 | 2,475% over the limit |
| Flow | 4 | 17 | 8 | March 31, 2006 | 363% over the limit |
| pH | 4 | 19 | 7 | June 30, 2012 | |
| BOD, 5-day, 20 deg. C | 5 | 18 | 6 | February 28, 2006 | 138% over the limit |
| Flow rate | 2 | 9 | 6 | March 31, 2002 | 20% over the limit |
| Di[2-ethylhexyl] phthalate [DEHP] | 4 | 9 | 4 | September 30, 2013 | 1,069% over the limit |
| LC50 Static 48Hr Acute Pimephales promelas | 0 | 3 | 3 | October 31, 2009 | 60% over the limit |
| Zinc, total [as Zn] | 7 | 19 | 2 | June 30, 2003 | 13% over the limit |
| Flow, maximum during 24 hr period | 2 | 14 | 2 | May 31, 2009 | 177% over the limit |
| Surfactants [MBAS] | 3 | 4 | 2 | March 31, 2009 | 26% over the limit |
| LC50 Static 48Hr Acute D. Pulex | 0 | 2 | 2 | October 31, 2009 | 9% over the limit |
| Acrylonitrile | 2 | 13 | 0 | ||
| Ethylbenzene | 2 | 13 | 0 | ||
| Solids, total suspended | 5 | 12 | 0 | ||
| Phosphorus, total [as P] | 0 | 8 | 0 | ||
| Butadiene, total | 1 | 7 | 0 | ||
| Styrene | 1 | 7 | 0 | ||
| LC50 Static 48Hr Acute Menidia | 4 | 6 | 0 | ||
| Oil & Grease | 3 | 6 | 0 | ||
| Iron, total [as Fe] | 0 | 6 | 0 | ||
| Copper, total [as Cu] | 7 | 5 | 0 | ||
| Nickel, total [as Ni] | 7 | 5 | 0 | ||
| Chromium, total [as Cr] | 6 | 5 | 0 | ||
| Lead, total [as Pb] | 6 | 5 | 0 | ||
| Acenaphthylene | 4 | 5 | 0 | ||
| Acenaphthene | 4 | 5 | 0 | ||
| Anthracene | 4 | 5 | 0 | ||
| Benzo[k]fluoranthene | 4 | 5 | 0 | ||
| Benzo[a]pyrene | 4 | 5 | 0 | ||
| Chrysene | 4 | 5 | 0 | ||
| Diethyl phthalate | 4 | 5 | 0 | ||
| Dimethyl phthalate | 4 | 5 | 0 | ||
| Fluoranthene | 4 | 5 | 0 | ||
| Fluorene | 4 | 5 | 0 | ||
| Hexachloroethane | 4 | 5 | 0 | ||
| Methylene chloride | 4 | 5 | 0 | ||
| Nitrobenzene | 4 | 5 | 0 | ||
| Phenanthrene | 4 | 5 | 0 | ||
| Pyrene | 4 | 5 | 0 | ||
| Benzo[a]anthracene | 4 | 5 | 0 | ||
| 1,2,4-Trichlorobenzene | 4 | 5 | 0 | ||
| 2-Nitrophenol | 4 | 5 | 0 | ||
| 2,4-Dichlorophenol | 4 | 5 | 0 | ||
| 2,4-Dimethylphenol | 4 | 5 | 0 | ||
| 2,4-Dinitrotoluene | 4 | 5 | 0 | ||
| 2,4-Dinitrophenol | 4 | 5 | 0 | ||
| 2,6-Dinitrotoluene | 4 | 5 | 0 | ||
| 4-Nitrophenol | 4 | 5 | 0 | ||
| 4,6-Dinitro-o-cresol | 4 | 5 | 0 | ||
| Naphthalene | 4 | 5 | 0 | ||
| Di-n-butyl phthalate | 4 | 5 | 0 | ||
| Hexachlorobutadiene | 4 | 5 | 0 | ||
| 3,4-Benzofluoranthene | 4 | 5 | 0 | ||
| Cyanide, total [as CN] | 3 | 5 | 0 | ||
| Carbon tetrachloride | 2 | 5 | 0 | ||
| 1,2-Dichloroethane | 2 | 5 | 0 | ||
| Chloroform | 2 | 5 | 0 | ||
| Toluene | 2 | 5 | 0 | ||
| Benzene | 2 | 5 | 0 | ||
| Chlorobenzene | 2 | 5 | 0 |
Cited to the EPA ICIS-NPDES limits and effluent violations files (ECHO download); up to 60 rows shown, most exceedances first.
Inspections, violations and enforcement
- 0Single-event violations
EPA’s single-event violation file, as loaded, holds no violation for NPDES CT0003131.
Velarion’s copy of EPA’s ICIS-NPDES files does not include the inspections, formal enforcement actions and informal enforcement actions files, so this page shows none of them. EPA’s free Detailed Facility Report on ECHO lists this permit’s inspections, enforcement actions and penalties.
Cited to the EPA ICIS-NPDES violation, inspection and enforcement files (ECHO download); up to 50 rows of each shown, newest first.
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EPA publishes a free Detailed Facility Report for every permit on ECHO: its compliance status quarter by quarter, its inspections, and its enforcement actions and penalties. EPA also sends free notices of new inspections and enforcement actions through ECHO Notify; enter NPDES ID CT0003131 there.
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Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.