Clean Water Act discharge permit · NPDES TXG310012

MUSTANG ISLAND ST 903S PLATFORM A, Corpus Christi, TX: NPDES TXG310012 discharge permit, effluent exceedances, inspections, penalties

EffectivePermit status
MinorDischarger class
28Pollutants under a numeric limit
2Pollutants with an effluent exceedance
0Inspections on file
0Formal enforcement actions

MUSTANG ISLAND ST 903S PLATFORM A, held by Tr Offshore, LLC, holds NPDES permit TXG310012. EPA’s file records it issued April 23, 2024 and expiring January 16, 2029.

MUSTANG ISLAND ST 903S PLATFORM A, Corpus Christi, Texas: Coverage under a general permit TXG310012, held by Tr Offshore, LLC; Effective; issued April 23, 2024, term to January 16, 2029.

Oil & Grease: 2 limits, 32 violations of any kind, 4 effluent exceedances, latest October 31, 2024, largest 341% over the limit.
Whole Effluent Toxicity [WET] - Americamysis bahia (formerly Mysidopsis bahia): 3 limits, 19 violations of any kind, 2 effluent exceedances, latest September 30, 2024, largest 99,999% over the limit.
Free Oil Visual Sheen: 2 limits, 29 violations of any kind, 0 effluent exceedances.
pH: 2 limits, 28 violations of any kind, 0 effluent exceedances.
Copper, total [as Cu]: 2 limits, 28 violations of any kind, 0 effluent exceedances.
Manganese, total [as Mn]: 2 limits, 28 violations of any kind, 0 effluent exceedances.
Zinc, total [as Zn]: 2 limits, 28 violations of any kind, 0 effluent exceedances.
Flow, in conduit or thru treatment plant: 2 limits, 28 violations of any kind, 0 effluent exceedances.
Whole Effluent Toxicity [WET] - M. beryllina: 3 limits, 17 violations of any kind, 0 effluent exceedances.
BOD, carbonaceous [5 day, 20 C]: 1 limit, 16 violations of any kind, 0 effluent exceedances.
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia): 2 limits, 14 violations of any kind, 0 effluent exceedances.
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Menidia beryllina: 2 limits, 14 violations of any kind, 0 effluent exceedances.
NOEC Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 2 limits, 14 violations of any kind, 0 effluent exceedances.
NOEC Lethal Static Renewal 7 Day Chronic Menidia beryllina: 2 limits, 14 violations of any kind, 0 effluent exceedances.
NOEC Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 2 limits, 14 violations of any kind, 0 effluent exceedances.
NOEC Sub-Lethal Static Renewal 7 Day Chronic Menidia beryllina: 2 limits, 14 violations of any kind, 0 effluent exceedances.
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 2 limits, 14 violations of any kind, 0 effluent exceedances.
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Menidia beryllina: 2 limits, 14 violations of any kind, 0 effluent exceedances.
LOEC Lethal Survival Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 2 limits, 14 violations of any kind, 0 effluent exceedances.
LOEC Lethal Survival Static Renewal 7 Day Chronic Menidia beryllina: 2 limits, 14 violations of any kind, 0 effluent exceedances.
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia): 2 limits, 14 violations of any kind, 0 effluent exceedances.
LOEC Sub-Lethal Growth Static Renewal 7 Day Chronic Menidia beryllina: 2 limits, 14 violations of any kind, 0 effluent exceedances.
Ammonia nitrogen, total, [as N] 30 day: 1 limit, 14 violations of any kind, 0 effluent exceedances.
Mercury, total [as Hg]: 1 limit, 14 violations of any kind, 0 effluent exceedances.
Produced water, TDS: 1 limit, 4 violations of any kind, 0 effluent exceedances.
Temperature Increase Deg. F: 1 limit, 4 violations of any kind, 0 effluent exceedances.
LC50 Pass/Fail Static 24Hr Acute Americamysis bahia (formerly Mysidopsis bahia): 1 limit, 3 violations of any kind, 0 effluent exceedances.
LC50 Pass/Fail Static 24Hr Acute Menidia beryllina: 1 limit, 3 violations of any kind, 0 effluent exceedances.

August 12, 2026: Under Review (State).
July 7, 2026: Under Review (State).
June 5, 2026: Under Review (State).
May 5, 2026: Under Review (State).
April 7, 2026: Under Review (State).
March 10, 2026: Under Review (State).
February 12, 2026: Under Review (State).

MUSTANG ISLAND ST 903S PLATFORM A among its neighbors

Its county holds 317, 24 of them major permits; TXG310012 is a minor permit.

Other permits in the county

18005A-21051 ALAMEDA ST FROM LOUISIANA AVE TO TEXAN TRAIL, Corpus Christi: TXR1506OJ, minor permit, discharging to THE DRAINAGE BASIN OUTFALLS INTO THE RECEIVING WAT, permit term to March 4, 2028
18156A SHIP CHANNEL WATERLINE & GAS LINE CROSSING, Corpus Christi: TXR1526PI, minor permit, discharging to CORPUS CHRISTI BAY, permit term to March 4, 2028
3L ENERGY SOLUTIONS, Corpus Christi: TXR05GK38, minor permit, permit term to August 13, 2026
AARON DR, Corpus Christi: TXR1521TT, minor permit, discharging to OSO CREEK BASIN, permit term to March 4, 2028
AEP MCKENZIE ROADSAXET SUBSTATIONS SITE PREPARATION, Corpus Christi: TXR1521XK, minor permit, discharging to OSO CREEK, permit term to March 4, 2028
AGUA DULCE COMPRESSOR STA, Banquete: TXR1514VQ, minor permit, discharging to PETRONILA CREEK, permit term to March 4, 2028
AGUA DULCE WWTF, Agua Dulce: TX0033367, minor permit, discharging to RAILROAD DITCH; AGUA DULCE CREEK, permit term to June 1, 2020
AIRPORT ROAD FROM HORNE ROAD TO MORGAN AVE, Corpus Christi: TXR1530PW, minor permit, discharging to CORPUS CHRISTI BAY, permit term to March 4, 2028
AL SPEIGHT MILITARY RAIL YARD, Corpus Christi: TXR1510RB, minor permit, discharging to CORPUS CHRISTI SHIP CHANNEL INNER HARBOR, permit term to March 4, 2028
AL SPEIGHT STORAGE YARD, Corpus Christi: TXR1503ZH, minor permit, discharging to CORPUS CHRISTI BAY, permit term to March 4, 2028

Identity

Facility as filed	MUSTANG ISLAND ST 903S PLATFORM A
Permittee as filed	Tr Offshore, LLC
NPDES ID	TXG310012
Permit status	Effective
Permit type	Coverage under a general permit
Discharger class	Minor discharger
Facility type	Not a publicly owned treatment works
Issued	April 23, 2024
Expiration date	January 16, 2029
Address	Corpus Christi, TX 78413

Effluent limits and exceedances

28Pollutants on file
28Under a numeric limit
28With 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
Oil & Grease	2	32	4	October 31, 2024	341% over the limit
Whole Effluent Toxicity [WET] - Americamysis bahia (formerly Mysidopsis bahia)	3	19	2	September 30, 2024	99,999% over the limit
Free Oil Visual Sheen	2	29	0
pH	2	28	0
Copper, total [as Cu]	2	28	0
Manganese, total [as Mn]	2	28	0
Zinc, total [as Zn]	2	28	0
Flow, in conduit or thru treatment plant	2	28	0
Whole Effluent Toxicity [WET] - M. beryllina	3	17	0
BOD, carbonaceous [5 day, 20 C]	1	16	0
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)	2	14	0
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Menidia beryllina	2	14	0
NOEC Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	2	14	0
NOEC Lethal Static Renewal 7 Day Chronic Menidia beryllina	2	14	0
NOEC Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	2	14	0
NOEC Sub-Lethal Static Renewal 7 Day Chronic Menidia beryllina	2	14	0
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	2	14	0
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Menidia beryllina	2	14	0
LOEC Lethal Survival Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	2	14	0
LOEC Lethal Survival Static Renewal 7 Day Chronic Menidia beryllina	2	14	0
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)	2	14	0
LOEC Sub-Lethal Growth Static Renewal 7 Day Chronic Menidia beryllina	2	14	0
Ammonia nitrogen, total, [as N] 30 day	1	14	0
Mercury, total [as Hg]	1	14	0
Produced water, TDS	1	4	0
Temperature Increase Deg. F	1	4	0
LC50 Pass/Fail Static 24Hr Acute Americamysis bahia (formerly Mysidopsis bahia)	1	3	0
LC50 Pass/Fail Static 24Hr Acute Menidia beryllina	1	3	0

Inspections, violations and enforcement

0Single-event violations

EPA’s single-event violation file, as loaded, holds no violation for NPDES TXG310012.

Inspections

EPA’s inspection file holds no inspection for NPDES TXG310012.

Formal enforcement and penalties

0 formal actions, 0 of them with a penalty assessed. Federal and state penalties are separate figures from separate authorities and are shown as each was filed, never added together.

Informal enforcement

Date	What EPA recorded	Agency
August 12, 2026	Under Review	State
July 7, 2026	Under Review	State
June 5, 2026	Under Review	State
May 5, 2026	Under Review	State
April 7, 2026	Under Review	State
March 10, 2026	Under Review	State
February 12, 2026	Under Review	State

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Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.

This public-records page covers NPDES permit TXG310012 for MUSTANG ISLAND ST 903S PLATFORM A in Corpus Christi, TX, held by Tr Offshore, LLC, with a status of Effective and a minor discharger class. The page lists 28 pollutants on file, all 28 under a numeric limit, and 2 with an effluent exceedance.