SHELL OFFSHORE, INC.
NPDES ID: GMG290103
S — SNC: Compliance schedule violation
The facility missed a deadline in its compliance schedule by more than 90 days.
Violations
February 28, 2026
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
January 31, 2026
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
December 31, 2025
NOAEC Lethal Static Renewal 48HR Acute Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (MO MAX)
DMR, Monitor Only - Overdue
NOEC Sub-Lethal Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Whole Effluent Toxicity [WET] - M. beryllina
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
NOAEC Lethal Static Renewal 48HR Acute Americamysis bahia (formerly Mysidopsis bahia)
0% over limit
Discharged 0 % against a permitted limit of 0 % (MO MAX)
DMR, Monitor Only - Overdue
Whole Effluent Toxicity [WET] - Americamysis bahia (formerly Mysidopsis bahia)
Limit violation
Discharged 1 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Numeric Violation
LOEC Sub-Lethal Growth Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
NOEC Lethal Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Whole Effluent Toxicity [WET] - M. beryllina
Limit violation
Discharged 1 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Numeric Violation
Whole Effluent Toxicity [WET] - Americamysis bahia (formerly Mysidopsis bahia)
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
Sanitary waste, residual chlorine
0% over limit
Discharged 0 mg/L against a permitted limit of 1 mg/L (DAILY MN)
DMR, Limited - Overdue
Critical Dilution
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
Critical Dilution
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
LOEC Lethal Survival Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
November 30, 2025
LOEC Sub-Lethal Growth Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Whole Effluent Toxicity [WET] - Americamysis bahia (formerly Mysidopsis bahia)
Limit violation
Discharged 1 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Numeric Violation
Sanitary waste, residual chlorine
20% over limit
Discharged 0.8 mg/L against a permitted limit of 1 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
Whole Effluent Toxicity [WET] - M. beryllina
Limit violation
Discharged 1 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Numeric Violation
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
LOEC Lethal Survival Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Discharge drill cuttings, formation oil
0% over limit
Discharged 1 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Numeric Violation
Sanitary waste, residual chlorine
0% over limit
Discharged 0 mg/L against a permitted limit of 1 mg/L (DAILY MN)
DMR, Limited - Overdue
NOEC Sub-Lethal Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
NOEC Lethal Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Whole Effluent Toxicity [WET] - Americamysis bahia (formerly Mysidopsis bahia)
Limit violation
Discharged 1 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Numeric Violation
October 31, 2025
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Flow
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
Well fluids, oil & grease
0% over limit
Discharged 0 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Overdue
Well fluids, free oil
0% over limit
Discharged 0 d against a permitted limit of 0 d (MO TOTAL)
DMR, Monitor Only - Overdue
Well fluids, oil & grease
0% over limit
Discharged 0 mg/L against a permitted limit of 29 mg/L (MO AVG)
DMR, Limited - Overdue
September 30, 2025
Produced water, oil and grease
31% over limit
Discharged 55 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Oil & grease, free oil
30% over limit
Discharged 54.6 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
August 31, 2025
Whole Effluent Toxicity [WET] - M. beryllina
Limit violation
Discharged 1 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Numeric Violation
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
July 31, 2025
Oil & grease, free oil
0% over limit
Discharged 0 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Overdue
Deck drainage, free oil
Limit violation
Discharged 2 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
June 30, 2025
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
May 31, 2025
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
Produced water, oil and grease
0% over limit
Discharged 0 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Overdue
Produced water, oil and grease
0% over limit
Discharged 0 mg/L against a permitted limit of 29 mg/L (MO AVG)
DMR, Limited - Overdue
Produced water, oil and grease
445% over limit
Discharged 229 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Produced water, oil and grease
62% over limit
Discharged 47 mg/L against a permitted limit of 29 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Whole Effluent Toxicity [WET] - Americamysis bahia (formerly Mysidopsis bahia)
Limit violation
Discharged 1 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Numeric Violation
Oil & grease, free oil
445% over limit
Discharged 229 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Deck drainage, free oil
Limit violation
Discharged 3 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
Whole Effluent Toxicity [WET] - M. beryllina
Limit violation
Discharged 1 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Numeric Violation
Temperature, water deg. centigrade
0% over limit
Discharged 0 deg C against a permitted limit of 0 deg C (VALUE)
DMR, Monitor Only - Overdue
April 30, 2025
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
Produced water, oil and grease
48% over limit
Discharged 43 mg/L against a permitted limit of 29 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Produced water, oil and grease
60% over limit
Discharged 67 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Produced water, oil and grease
31% over limit
Discharged 55 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Oil & grease, free oil
60% over limit
Discharged 67 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
March 31, 2025
Whole Effluent Toxicity [WET] - Americamysis bahia (formerly Mysidopsis bahia)
Limit violation
Discharged 1 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Numeric Violation
Produced water, flow
0% over limit
Discharged 0.0131355 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
Deck drainage, free oil
Limit violation
Discharged 2 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
February 28, 2025
Drilling fluids, discharge rate
0% over limit
Discharged 1.01000001 MGD against a permitted limit of 1.01 MGD (MX HR RT)
DMR, Limited - Numeric Violation
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Produced water, flow
0% over limit
Discharged 0.0052605 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
January 31, 2025
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
Produced water, flow
0% over limit
Discharged 0.008694 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
Deck drainage, free oil
Limit violation
Discharged 2 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Deck drainage, free oil
Limit violation
Discharged 2 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
December 31, 2024
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
Cooling Water Intake Velocity
12% over limit
Discharged 0.1708 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
November 30, 2024
Flow
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO MAX)
DMR, Monitor Only - Overdue
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
NOAEC Lethal Static Renewal 48HR Acute Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (MO MAX)
DMR, Monitor Only - Overdue
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
Critical Dilution
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Whole Effluent Toxicity [WET] - Americamysis bahia (formerly Mysidopsis bahia)
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
NOAEC Lethal Static Renewal 48HR Acute Americamysis bahia (formerly Mysidopsis bahia)
0% over limit
Discharged 0 % against a permitted limit of 0 % (MO MAX)
DMR, Monitor Only - Overdue
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Oil & grease, free oil
31% over limit
Discharged 55 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
NOEC Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
NOEC Sub-Lethal Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
LOEC Lethal Survival Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
NOEC Lethal Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
LOEC Sub-Lethal Growth Static Renewal 7 Day Chronic Menidia beryllina
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Cooling Water Intake Velocity
10% over limit
Discharged 0.16775 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
LOEC Lethal Survival Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Critical Dilution
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
NOEC Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)
0% over limit
Discharged 0 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Produced water, oil and grease
31% over limit
Discharged 55 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Whole Effluent Toxicity [WET] - M. beryllina
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Monitor Only - Overdue
October 31, 2024
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Cooling Water Intake Velocity
20% over limit
Discharged 0.183 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
Cooling Water Intake Velocity
10% over limit
Discharged 0.16775 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
September 30, 2024
Critical Dilution
0% over limit
Discharged 20 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
Deck drainage, free oil
Limit violation
Discharged 3 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Oil & grease, free oil
0% over limit
Discharged 0 mg/L against a permitted limit of 42 mg/L (DAILY MX)
DMR, Limited - Overdue
Whole Effluent Toxicity [WET] - M. beryllina
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Overdue
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Whole Effluent Toxicity [WET] - Americamysis bahia (formerly Mysidopsis bahia)
0% over limit
Discharged 0 pass=0;fail=1 against a permitted limit of 0 pass=0;fail=1 (VALUE)
DMR, Limited - Overdue
NOAEC Lethal Static Renewal 48HR Acute Americamysis bahia (formerly Mysidopsis bahia)
0% over limit
Discharged 80 % against a permitted limit of 0 % (MO MAX)
DMR, Monitor Only - Overdue
Cooling Water Intake Velocity
14% over limit
Discharged 0.17385 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
NOAEC Lethal Static Renewal 48HR Acute Menidia beryllina
0% over limit
Discharged 80 % against a permitted limit of 0 % (MO MAX)
DMR, Monitor Only - Overdue
Critical Dilution
0% over limit
Discharged 20 % against a permitted limit of 0 % (VALUE)
DMR, Monitor Only - Overdue
August 31, 2024
Cooling Water Intake Velocity
14% over limit
Discharged 0.17385 m/sec against a permitted limit of 0.1525 m/sec (MAXIMUM)
DMR, Limited - Numeric Violation
Deck drainage, free oil
Limit violation
Discharged 2 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
Deck drainage, free oil
Limit violation
Discharged 1 d against a permitted limit of 0 d (MO TOTAL)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
August 1, 2026 (5 days ago)