Clean Water Act discharge permit · NPDES MSP091451
WESTLAKE CHEMICALS & VINYLS LLC, Aberdeen, MS: NPDES MSP091451 discharge permit, effluent exceedances, inspections, penalties
- EffectivePermit status
- MinorDischarger class
- 48Pollutants under a numeric limit
- 2Pollutants with an effluent exceedance
WESTLAKE CHEMICALS & VINYLS LLC holds NPDES permit MSP091451, which discharges to Ms0024783 - Aberdeen Potw. EPA’s file records it issued March 15, 2021 and expiring February 28, 2026. The status and dates are as EPA’s permit file stood when Velarion loaded it (October 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | WESTLAKE CHEMICALS & VINYLS LLC |
|---|---|
| Permittee as filed | WESTLAKE CHEMICALS & VINYLS LLC |
| NPDES ID | MSP091451 |
| Permit status | Effective |
| Permit type | Individual industrial user permit |
| Discharger class | Minor discharger |
| Facility type | Not a publicly owned treatment works |
| Issued | March 15, 2021 |
| Expiration date | February 28, 2026 |
| Issuing agency | MDEQ |
| Address | Aberdeen, MS 39790 |
| Receiving water | MS0024783 - ABERDEEN POTW |
| NAICS | 325211 – Plastics Material and Resin Manufacturing |
| SIC | 2821 – Plastics Materials And Resins |
| Other EPA IDs (FRS) | RCRA handler MSD007031230; ICIS-AIR source MS0000002809500014 |
Cited to the EPA ICIS-NPDES permit file (ECHO download) and EPA’s NAICS/SIC and component files, the same download; cross-program IDs from EPA’s FRS facility-registry crosswalk.
Effluent limits and exceedances
- 48Pollutants on file
- 48Under a numeric limit
- 3With a violation of any kind
- 2With 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.
| Pollutant or measure | Limits | Violations, any kind | Effluent exceedances | Latest exceedance | Largest exceedance, as filed |
|---|---|---|---|---|---|
| BOD, 5-day, 20 deg. C | 4 | 6 | 2 | June 30, 2025 | 20% over the limit |
| Solids, total suspended | 4 | 5 | 1 | March 31, 2026 | 9% over the limit |
| Flow, in conduit or thru treatment plant | 2 | 2 | 0 | ||
| Zinc, total recoverable | 4 | 0 | 0 | ||
| Carbon tetrachloride | 4 | 0 | 0 | ||
| 1,2-Dichloroethane | 4 | 0 | 0 | ||
| Chloroform | 4 | 0 | 0 | ||
| Toluene | 4 | 0 | 0 | ||
| Benzene | 4 | 0 | 0 | ||
| Acenaphthene | 4 | 0 | 0 | ||
| Anthracene | 4 | 0 | 0 | ||
| Chlorobenzene | 4 | 0 | 0 | ||
| Diethyl phthalate | 4 | 0 | 0 | ||
| Dimethyl phthalate | 4 | 0 | 0 | ||
| Ethylbenzene | 4 | 0 | 0 | ||
| Fluoranthene | 4 | 0 | 0 | ||
| Fluorene | 4 | 0 | 0 | ||
| Hexachloroethane | 4 | 0 | 0 | ||
| Methyl chloride [Chloromethane] | 4 | 0 | 0 | ||
| Methylene chloride | 4 | 0 | 0 | ||
| Nitrobenzene | 4 | 0 | 0 | ||
| Phenanthrene | 4 | 0 | 0 | ||
| Pyrene | 4 | 0 | 0 | ||
| Tetrachloroethylene | 4 | 0 | 0 | ||
| 1,1-Dichloroethane | 4 | 0 | 0 | ||
| 1,1-Dichloroethylene | 4 | 0 | 0 | ||
| 1,1,1-Trichloroethane | 4 | 0 | 0 | ||
| 1,1,2-Trichloroethane | 4 | 0 | 0 | ||
| 1,2-Dichlorobenzene | 4 | 0 | 0 | ||
| 1,2-Dichloropropane | 4 | 0 | 0 | ||
| trans-1,2-Dichloroethylene | 4 | 0 | 0 | ||
| 1,2,4-Trichlorobenzene | 4 | 0 | 0 | ||
| 1,3-Dichlorobenzene | 4 | 0 | 0 | ||
| 1,4-Dichlorobenzene | 4 | 0 | 0 | ||
| 2-Nitrophenol | 4 | 0 | 0 | ||
| 4-Nitrophenol | 4 | 0 | 0 | ||
| 4,6-Dinitro-o-cresol | 4 | 0 | 0 | ||
| Naphthalene | 4 | 0 | 0 | ||
| Di[2-ethylhexyl] phthalate [DEHP] | 4 | 0 | 0 | ||
| Di-n-butyl phthalate | 4 | 0 | 0 | ||
| Vinyl chloride | 4 | 0 | 0 | ||
| Trichloroethylene | 4 | 0 | 0 | ||
| Hexachlorobenzene | 4 | 0 | 0 | ||
| Hexachlorobutadiene | 4 | 0 | 0 | ||
| 1,3-Dichloropropylene | 4 | 0 | 0 | ||
| 1,3-Dichloropropene | 4 | 0 | 0 | ||
| Chloroethane | 4 | 0 | 0 | ||
| pH | 2 | 0 | 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 MSP091451.
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.
Watch this permit
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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 MSP091451 there.
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Figures from EPA’s ICIS-NPDES download, loaded October 14, 2026.