FACT SHEET AND SUPPLEMENTAL INFORMATION
FOR THE FINAL REISSUANCE OF
THE NPDES GENERAL PERMIT FOR NEW AND EXISTING SOURCES
IN THE OFFSHORE SUBCATEGORY OF
THE OIL AND GAS EXTRACTION POINT SOURCE CATEGORY FOR
THE WESTERN AND CENTRAL PORTION OF THE OUTER CONTINENTAL SHELF OF
THE GULF OF MEXICO (GMG290000)
May 10, 2023
U.S. Environmental Protection Agency
Region 6
1201 Elm Street, Suite 500
Dallas, TX 75270
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I. Legal Basis
The Clean Water Act (CWA or the Act) renders it unlawful to discharge pollutants to
waters of the United States from any point source, except as authorized by the Act, which may
include issuance of an NPDES permit. 33 U.S.C. §§ 1311(a), 1342(a). CWA section 402, 33
U.S.C. section 1342, authorizes the Environmental Protection Agency (EPA) to issue National
Pollutant Discharge Elimination System (NPDES) permits allowing discharges on the condition
they will meet certain requirements, including CWA sections 301, 304, 306, 401 and 403. Those
statutory provisions require NPDES permits include effluent limitations for authorized
discharges that: (1) meet standards reflecting levels of technological capability; (2) comply with
the EPA-approved state water quality standards; (3) comply with other state requirements
adopted under authority retained by states under CWA section 510, 33 U.S.C. section 1370; and,
(4) cause no unreasonable degradation to the territorial seas, waters of the contiguous zone, or
the oceans.
CWA section 301 requires compliance with "best conventional pollution control
technology" (BCT) and "best available pollution control technology economically achievable"
(BAT) no later than March 31, 1989. CWA section 306 requires compliance with New Source
Performance Standards (NSPS) no later than the effective date of such standards. Accordingly,
three types of technology-based effluent limitations are included in the proposed permit. With
regard to conventional pollutants, i.e., pH, BOD, oil, and grease, TSS, and fecal coliform, CWA
section 301(b)(1)(E) requires effluent limitations based on BCT. With regard to nonconventional
and toxic pollutants, CWA sections 301(b)(2)(A), (C), and (D) require effluent limitations based
on BAT. For New Sources, CWA section 306 requires effluent limitations based on New Source
Performance Standards (NSPS). Final effluent guidelines specifying BCT, BAT, and NSPS for
the Offshore Subcategory of the Oil and Gas Point Source Category (40 CFR 435, Subpart A)
were issued January 15, 1993, and were published at 58 FR 12454 on March 4, 1993. Those
guidelines were modified on January 22, 2001 (see 66 FR 6850, January 22, 2001), to include
technology based treatment standards for discharges associated with the industry's use of
synthetic based drilling fluids.
II. Regulatory Background
On April 3, 1981 (see 46 FR 20284), the EPA published the final general NPDES permit,
TX0085642, which authorized discharges from facilities located seaward of the outer boundary
of the territorial seas (as defined by 33 U.S.C. 1362(8)) off Louisiana and Texas. The 1981
general permit implemented "Best Practicable Control Technology Currently Available" (BPT),
as established by effluent guidelines for the Offshore Subcategory (see 40 CFR 435). The
permits expired April 3, 1983.
The EPA reissued the general permit on September 15, 1983 (48 FR 41494), with an
expiration date of June 30, 1984. The permit was issued for a short period of time because
promulgation of National Effluent Limitations Guidelines for Best Available Technology
Economically Achievable were expected by 1983 and again by 1984. The limitations contained
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in the permit were unchanged in the 1984 reissuance; however, some changes were made for
facilities located near the Flower Garden Banks.
On July 9, 1986 (51 FR 24897), the EPA reissued the general permit. In that action the
EPA Region 6 issued a joint permit with Region 4 authorizing discharges from facilities located
throughout the Gulf of Mexico seaward of the 3-mile Clean Water Act territorial seas. That
permit, numbered GMG280000, prohibited discharge of oil based drilling fluids, oil
contaminated drilling fluids, drilling fluids containing diesel oil, and drill cuttings generated
using oil based drilling fluids. New limits were included in the permit for suspended particulate
phase toxicity in drilling fluids, the drilling fluid discharge rate near areas of biological concern,
and for free oil in drilling fluids and drill cuttings. The permit expired on July 1, 1991.
On November 19, 1992, the EPA Region 6 reissued the NPDES general permit for the
Western Gulf of Mexico Outer Continental Shelf (57 FR 54642), GMG290000, covering
operators of lease blocks in the Offshore Subcategory of the Oil and gas Extraction Point Source
Category located seaward of the outer boundary of the territorial seas of Texas and Louisiana.
As a part of that reissuance, new limits for produced water toxicity were added, as well as new
limits for cadmium and mercury in stock barite, and a prohibition on the discharge of drilling
fluids to which mineral oil has been added. That general permit was modified on December 3,
1993, to implement Offshore subcategory effluent limitations guidelines promulgated March 4,
1993 (58 FR 12504), and to include more accurate calculations of produced water critical
dilutions. A general permit covering New Sources in that same area of coverage was issued and
combined with the Western Gulf of Mexico Outer Continental Shelf general permit on August 9,
1996 (61 FR 41609). The permit expired on November 19, 1997 and was reissued in two parts
on November 2, 1998 (63 FR 58722), and April 19, 1999 (64 FR 19156).
In the 1998 reissuance, the EPA Region 6 authorized new discharges of seawater and
freshwater to which treatment chemicals, such as biocides and corrosion inhibitors, have been
added. The maximum discharge rate limit for produced water was removed. To account for
advances in drilling fluid technology, the permit was modified on December 18, 2001 (66 FR
65209), to authorize discharges associated with the use of synthetic based drilling fluids.
Additional monitoring requirements were also included at that time to address hydrostatic testing
of existing piping and pipelines and those discharges were authorized. That permit expired on
November 3, 2003.
The general permit was reissued on October 7, 2004 (69 FR 60150). With that reissuance,
the EPA included produced water monitoring requirements for facilities located in the hypoxic
zone. The permit was issued for a three-year term rather than the typical five-year term so that
the results from the produced water hypoxia study could be addressed in a timely manner if
additional permit conditions were found to be warranted. In the 2007 permit reissuance (72 FR
31575), requirements to comply with new cooling water intake structure regulations were
included. Sub-lethal effects were required to be measured for whole effluent toxicity testing.
New testing methods were allowed for monitoring cadmium and mercury in stock barite. That
permit expired September 30, 2012.
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The EPA reissued the permit on September 28, 2012 (77 FR 61605). Operators are
required to file electronic Notice of Intent and Discharge Monitoring Reports. The permit
required characterization studies for produced water and water-based drilling fluids, respectively,
so the EPA could evaluate whether those discharges might contribute heavy metals at a level
toxic to aquatic life. Other major changes included toxicity testing requirements for hydrate
control fluids, spill prevention best management practices, and allowing the discharge of limited
amount of drilling fluids with cuttings due to the testing of subsea safety valves. The permit
expired September 30, 2017.
The EPA reissued the permit on September 19, 2017 ( 82 FR 45845). The permit
removed the requirements to submit eNOIs 24 hours prior to discharging, extended Notice of
Termination (NOT) deadline to within one year after termination, allowed paper NOIs when the
eNOI system is unavailable, allowed the primary operator to require day-to-day vessel operators
to file eNOIs for their activities, increased the time to collect a produced water oil and grease
sample from 30 minutes to 2 hours after a sheen is observed, reduced the cooing water intake
velocity monitoring frequency, restored the monitoring exception for properly operated Marine
Sanitation Devices (MSDs), increased the deadline to submit the Industry-wide Study Plan for
well treatment, completion, and workover fluids was changed from 6 months to 18 months, and
allowed submittal of SEAMAP data instead of entrainment monitoring for cooling water intake.
Various other changes were included to clarify permit requirements. The permit expired on
September 30, 2022.
The EPA proposed permit renewal in the Federal Register Notice on July 22, 2022. In the
proposed permit renewal, the EPA proposed several major changes, discussed in the document
entitled "Fact Sheet And Supplemental Information For The Proposed Reissuance Of The
NPDES General Permit For New And Existing Sources In The Offshore Subcategory Of The Oil
And Gas Extraction Point Source Category For The Western Portion Of The Outer Continental
Shelf Of The Gulf Of Mexico (GMG290000)". A 60-day public comment period ending
September 20, 2022, was provided. The EPA received comments from fourteen entities
including: 1) the Joint Trades, 2) BP Exploration and Production Inc., 3) Beacon Offshore
Energy, 4) Bureau of Safety and Environmental Enforcement - Gulf of Mexico OCS Region, 5)
CETCO Energy Services, 6) Transocean Offshore Deepwater Drilling Inc., 7) International
Association of Drilling Contractors, 8) Chevron U.S.A. Inc., 9) Shell Exploration & Production
Company, 10) Anonymous, 11) Center for Biological Diversity (CBD), 12) Helen Kimball-
Brooke, 13) Virginia Gomez, and 14) Daniel Gregg. While most of comments from regulated
communities focused on operation requirements, comments from CBD mainly focused on
regulatory requirements.
III. Coverage of Facilities and Locations
A facility means a platform, rig, ship, and any surface/sub-surface fixed or mobile
structure from where exploration, development, or production operations are performed. The
permit coverage area consists of lease areas that are located in and discharging to Federal waters
in the Gulf of Mexico specifically located in the Central to Western portions of the Gulf of
Mexico (GMG290000). The lease areas under Region 6 that begin in the Central portion include:
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Chandeleur, Chandeleur East, Breton Sound, Main Pass, Main Pass South and East, Viosca
Knoll (but only those blocks under Main Pass South and East; the Viosca Knoll blocks between
Main Pass and Mobile are under the EPA Region 4 jurisdiction), South Pass, South Pass South
and East, West Delta, West Delta South, Mississippi Canyon, Atwater Valley, Lund, and Lund
South. These named lease areas and all lease areas westward are part of Region 6. If facilities
located in the Louisiana or Texas territorial seas want to discharge to areas beyond the 3-mile
territorial seas as defined under the Clean Water Act, operators need to file Notice of Intent
(NOI) under the authority of this permit, GMG290000. But, facilities located in the Louisiana or
Texas territorial seas and discharges to territorial seas must be covered under LAG260000 or
TXG260000, respectively. Facilities located in the Louisiana or Texas territorial seas are not
authorized to discharge drilling fluids and drill cuttings pursuant to the Offshore Subcategory
guidelines (40 CFR 435.13 and 435.14).
IV. Types of Discharges Covered
The discharges proposed to be authorized by the reissued permit are listed below. The
definitions of the waste streams are based on those given in the Offshore Subcategory Effluent
Limitations Guidelines (40 CFR 435, Subpart A), except for miscellaneous discharges which
were not covered by those guidelines. Most of the authorized waste streams are retained from the
current 2012 issued permit.
A. Drilling fluids - the circulating fluid (mud) used in the rotary drilling of wells to
clean and condition the hole and to counterbalance formation pressure. Classes of drilling fluids
are:
(a) "Water-Based Drilling Fluid" means the continuous phase and
suspending medium for solids is a water-miscible fluid, regardless of the presence
of oil.
(b) "Non-Aqueous Drilling Fluid" means the continuous phase and
suspending medium for solids is a water-immiscible fluid, such as oleaginous
materials (e.g., mineral oil, enhanced mineral oil, paraffinic oil, Ci6-Ci8 internal
olefins, and C8-C16 fatty acid/2-ethylhexyl esters).
(i) "Oil-Based" means the continuous phase of the drilling
fluid consists of diesel oil, mineral oil, or some other oil, but contains no
synthetic material or enhanced mineral oil.
(ii) "Enhanced Mineral Oil-Based" means the continuous
phase of the drilling fluid is enhanced mineral oil.
(iii) "Synthetic-Based" means the continuous phase of the
drilling fluid is a synthetic material or a combination of synthetic
materials.
B. Drill cuttings - the particles generated by drilling into subsurface geologic
formations including cured cement carried out from the wellbore with the drilling fluid.
Examples of drill cuttings include small pieces of rock varying in size and texture from fine silt
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to gravel. Drill cuttings are generally generated from solids control equipment and settle out and
accumulate in quiescent areas in the solids control equipment or other equipment processing
drilling fluid (i.e., accumulated solids).
(a) "Wet Drill Cuttings" means the unaltered drill cuttings and adhering
drilling fluid and formation oil carried out from the wellbore with the drilling
fluid.
(b) "Dry Drill Cuttings" means the residue remaining in the retort vessel
after completing the retort procedure specified in Appendix 7 of 40 CFR 435,
Subpart A.
C. Deck drainage - any waste resulting from deck washings, spillage, rainwater, and
runoff from gutters and drains including drip pans and work areas within facilities subject to this
permit. A use of biocide for sump/drain systems to comply with proper operation and
maintenance requirements is permitted and toxicity test for such a discharge of drainage is not
required.
D. Produced water - the water brought up from the hydrocarbon-bearing strata during
the extraction of oil and gas, and can include formation water, injection water, and any chemicals
added downhole or during the oil/gas/water separation process.
Produced water generated from the monoethylene glycol (MEG) reclamation processes
including salt slurry generated from the salt centrifuge unit is regulated as produced water.
However, separate monitoring requirements must be complied with if such salt slurry is not
mixed and discharged with produced water waste stream.
E. Produced sand - slurried particles used in hydraulic fracturing, the accumulated
formation sands, and scale particles generated during production. Produced sand also includes
desander discharge from produced water waste stream and blowdown of water phase from the
produced water treatment system.
F. Well treatment, completion fluids and workover fluids (TCW Fluids) - well
treatment fluids are any fluids used to restore or improve productivity by chemically or
physically altering hydrocarbon-bearing strata after a well has been drilled; well completion
fluids are salt solutions, weighted brines, polymers, and various additives used to prevent
damage to the well bore during operations which prepare the drilled well for hydrocarbon
production; and workover fluids are salt solutions, weighted brines, polymers, or other specialty
additives used in a producing well to allow for maintenance, repair or abandonment procedures.
Packer fluids, low solids fluids between the packer, production string and well casing, are
considered to be workover fluids and must meet the effluent requirements imposed on workover
fluids. The 2012 permit clarified that propping agents returned with well treatment fluids or
produced water meet the definition of produced sands. Fracking fluids are considered well
treatment fluids under this permit.
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G. Sanitary waste - human body waste discharged from toilets and urinals.
H. Domestic waste - material discharged from galleys, sinks, showers, safety showers,
eye wash stations, hand washing stations, fish cleaning stations, and laundries.
I. Miscellaneous discharges -
Aqueous film forming foam (AFFF) - AFFF must be collected and stored for onshore disposal
unless the vessel uses a non-fluorinated or alternative foaming agent.
Blowout preventer control fluid - fluid used to actuate the hydraulic equipment on the blow-out
preventer. This permit action clarifies that this discharge includes fluid from the subsea wireline
"grease-head."
Boiler blowdown - discharges from boilers necessary to minimize solids build-up in the boilers,
including vents from boilers and other heating systems.
Bulk transfer operations powder - de minimis amounts of bulk product (e.g., barite, cement,
etc.) that may be released during transfers from supply boats to a drilling rig.
Desalinization unit discharge - wastewater associated with the process of creating freshwater
from seawater.
Diatomaceous earth filter media - filter media used to filter seawater or other authorized
completion fluids and subsequently washed from the filter.
Excess cement slurry - the excess mixed cement pumped to wells, including additives and
wastes from equipment washdown, after a cementing operation. Mixed cement for equipment
testing purposes does not meet the definition of excess cement slurry.
Hydrate control fluids - fluids used to prevent, retard, or mitigate the formation of hydrates in
and on drilling equipment, process equipment and piping.
Mud, cuttings and cement at the sea floor - discharges that occur at the seafloor prior to
installation of the marine riser and during marine riser disconnect, well abandonment and
plugging operations.
Pipeline brines - brines used for pipeline/equipment preservation.
Source water and source sand - water from non-hydrocarbon bearing formations for the
purpose of pressure maintenance or secondary recovery including the entrained solids.
Subsea cleaning fluids - acidic cleaning agents used to dissolve marine deposits on subsea
equipment during subsea maintenance and intervention activities to assure proper seating of
equipment operating and to avoid ingress of extremely high subsea pressures and egress (losses
of containment) of fluids to the environment
Subsea production discharges - include: subsea wellhead preservation fluids, subsea
production control fluid, umbilical steel tube storage fluid, leak tracer fluid, and riser tensioner
fluids.
Uncontaminated or treated ballast/bilge water - seawater added or removed to maintain
proper draft (ballast water) or water from a variety of sources that accumulates in the lowest part
of the vessel/facility (bilge water) without contact with or addition of chemicals, oil, or other
wastes, or being treated for removal of contaminants prior to discharge. These definitions are
modified from the current definitions to distinguish ballast water and bilge water and to add the
treated ballast water and bilge water to the definition.
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Uncontaminated freshwater - freshwater which is discharged without the addition or contact of
treatment, chemicals, oil, or other wastes; included are: (1) discharges of excess freshwater that
permit the continuous operation of fire control and utility lift pumps; (2) excess freshwater from
pressure maintenance and secondary recovery projects; (3) water used during training and testing
of personnel in fire protection; and (4) water used to pressure test new piping.
Uncontaminated seawater - seawater which is returned to the sea without the addition or
contact of treatment chemicals, oil, or other wastes. Included are: (1) discharges of excess
seawater which permit the continuous operation of fire control and utility lift pumps; (2) excess
seawater from pressure maintenance and secondary recovery projects; (3) water released during
the training and testing of personnel in fire protection; (4) seawater used to pressure test piping;
(5) once through noncontact cooling water which has not been treated with biocides, and (6)
seawater not treated by chemicals used during Dual Gradient Drilling.
J. Chemically Treated Seawater and Freshwater - seawater or freshwater to which
corrosion inhibitors, scale inhibitors, and/or biocides have been added. The existing permitted
discharges in the current permit include:
1. Excess seawater which permits the continuous operation of fire control
and utility lift pumps,
2. Excess seawater from pressure maintenance and secondary recovery
projects,
3. Water released during training of personnel in fire protection,
4. Seawater used to pressure test piping and pipelines,
5. Ballast water,
6. Once through non-contact cooling water,
7. Seawater used as piping or equipment preservation fluids, and
8. Seawater used during Dual Gradient Drilling.
9. Well operations other than those covered by the other sections of Part I.B
of the permit.
The seawater used during Dual Gradient Drilling (DGD) is a practice of maintaining two
effective fluid gradients in the wellbore annulus while drilling. The denser gradient is below the
sea floor and the less dense gradient is above the sea floor. There are two discharges associated
with DGD: one is seawater used to provide hydraulic power to Mud Lift Pump; and another is
seawater used to provide static head in riser during DGD. Depending on the system design,
corrosion inhibitors and biocides may need to be used to prevent corrosion and properly operate
and maintain the DGD system.
For a sub-sea discharge of chemically treated seawater or freshwater used for piping and
equipment preservation, where to collect discharge samples is not practical, the EPA authorizes
those discharges by permitting the operator to conduct the required toxicity tests prior to the use
of the product.
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The EPA, in 2012, determined that toxicity tests are not required for miscellaneous
discharges treated by bromide, chlorine, or hypochlorite. But, uses of bromide, chlorine, or
hypochlorite are still required to be in compliance with the technology-based quantity limits.
V. Significant Changes from the Proposed Permit
Significant changes from the proposed permit include.
1. Well, heads, pipelines, jumpers, and associated infrastructures connected to the
facility are considered part of the host facility even when the infrastructure
crosses lease block boundaries.
2. NOI requirements allow for all vessels, to be able to file one valid NOI when
performing jobs in the same lease block, if jobs are performed for the same
designated operator.
3. Operators who filed under the previous permit have an additional 30 days to
submit eNOI, if the system is unavailable during the 60 day renewal period. These
operators are covered under the reissued permit for up to 90 days.
4. Only new operators, not covered under the previous permit, can submit temporary
NOIs when system is unavailable. Due date and coverage for temporary NOI
extended 14 days, after the system becomes available, if the system remains
unavailable after 14 days.
5. Removed continuous monitoring language from cooling water intake
requirements.
6. Removed the additional requirements for a signed agreement for transfers.
7. Flow rate monitoring for Well Treatment Fluids, Completion Fluids, and
Workover Fluids.
8. Characteristic Assessment requirements for Well Treatment Fluids, Completion
Fluids, and Workover Fluids have been removed.
9. For Sanitary Waste, all limits must be complied with, in the event the Marine
Sanitation Device is not properly operating or not operating.
10. Cooling water intake structure operation for New Fixed Facilities that Employ
Sea Chests as Intake Structures and New Fixed Facilities that do not employ sea
chests as intake structures, require development, and implementation of operation
and maintenance plans, with reporting requirements for numeric exceedances.
11. All facilities are subject to monitoring requirements if they discharged during said
monitoring period, regardless of whether the discharge lasted the full period
12. Methods and/or calculations for estimated flow must be documented.
13. Sample type for oil and grease is grab or composite.
14. The use of other disinfection technologies, including, but not limited to, bio-
membrane filtration and ultra-violet light are allowed as substitutes for systems
that use chlorine, provided that the MSD is approved by the U.S. Coast Guard and
results in equivalent or improved disinfection of the Sanitary Waste stream to that
considered in the ELG. TRC monitoring is not required for alternative MSDs that
do not use chlorine, when the system is not properly operating or not operating,
unless a chlorine based product is used as a backup disinfectant.
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15. Operators must flush and capture the materials contained in pipelines, umbilicals,
and other equipment prior to disconnection. No releases or discharges of fluid
from pipelines, umbilicals, and/or other equipment that have not been fully
flushed prior to being disconnected or cut from the facility are authorized under
this NPDES permit.
16. Calculation for WET critical dilutions and testing frequencies is based on
calendar year
17. Waiver for the minimum number of samples to be collected for WET tests, should
the effluent cease discharging for produced water.
18. For Treatment, Completion, and Workover discharges, acute WET results can be
derived from chronic WET test.
19. Compliance schedule for WET acute limits related to Treatment, Completion, and
Workover discharges and sample holding time of 72 hours.
20. No approved Alternative Test Procedure (ATP) for WET, however they can be
requested at any time following 40 CFR 136.5.
21. 72 hour hold time for WET samples for Chemically Treated Miscellaneous
Discharges
22. For Chemically Treated Miscellaneous Discharges, non-continuous discharges are
discharges that occur less than or equal to once per week and last less than 24
hours. These discharges shall be monitored once per discharge.
23. State general permit or state individual permit may be required in addiiton to
authorization under this permit.
24. Defines decommissioning and Subsea Cleaning Fluids.
25. 7-day chronic toxicity requirements for Well Treatment Fluids, Completion
Fluids, and Workover Fluids has been moved from limitations to monitoring
section, to provide clarity that chronic is monitoring only.
26. Free oil language has been updated to reference DMRs and twenty-four hour
reporting requirements.
27. Part I.C. reflects Other Limitations, Prohibitions and Discharges not Authorized.
Moved Limitations on Coverage section in Part I.A.I to Part I.C for Prohibitions
and Discharges Not Authorized.
28. Permit does not authorize radioactive materials that are under the jurisdiction of
the Nuclear Regulatory Commission (NRC).
29. Miscellaneous Discharges of Water Which Have Been Chemically Treated
includes discharges from well operations other than those covered by other
sections of Part I.B of the permit.
30. Corrections to the Permit Summary Table. Table is for reference only
31. Corrected data for Discharge Monitoring Reports (DMRs) and Other Reports
must be submitted as soon as the error has been identified but no later than the
following quarter. Submittal of corrected data does not excuse any permit
violation.
32. If Offshore 24-Hour Reporting Application Portal is not available, an email shall
be sent within 24 hours of occurrence of specified violations and electronic report
shall be submitted within 14 days of the system becoming available.
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33. A facility map that delineates authorized discharge locations and type must be
submitted, as an attachment, when filing the eNOI.
34. Updated language to provide clarity that timely updates to "CDX" are required, in
lieu of "eNOI".
35. Numeric exceedances of maximum through-screen design intake velocity and
dates must also be included on DMRs, for all new facilities required to comply
with intake structure monitoring requirements.
36. Definition of Mobile Offshore Drilling Unit (MODU) has been removed from the
permit because it does not exist in the Code of Federal Regulations. Part I.A.2 has
been updated to provide examples of MODUs.
37. Civil and administrative penalty amounts have been updated to reflect updated
statutory amounts.
38. Once a month temperature monitoring for produced water.
Change 1. Well, heads, pipelines, junipers and associated infrastructures connected to the facility
are considered part of the host facility even when the infrastructure crosses lease block boundaries.
The Joint Trades requested that the proposed permit include language to clarify that well, heads,
pipelines, jumpers and associated infrastructures connected to the facility be considered part of the host
facility even when the infrastructure crosses lease block boundaries. The recommended revised language
provides additional clarity on the types of equipment and infrastructure associated with a host facility and
provides additional context for the regulated community to understand the intent of the permit. EPA
recognizes that this practice was allowed in the previous permit, therefore, to provide clarity, EPA
updated the description of infrastructure as stated above.
Change 2. NOI requirements allow for all vessels, to be able to file one valid NOI when performing
jobs in the same lease block, if jobs are performed for the same designated operator. The Joint
Trades requested that EPA broaden the NOI requirements to allow for all vessels, and not specifically
drilling vessels, to be able to file one valid NOI when performing well jobs (not specifically drilling jobs)
within the same lease block in order to broaden the types of operations a MODU or vessel may undertake.
The EPA updated the language to address the filing of NOIs for vessels performing operations other than
drilling. For the final permit, vessels that move are only required to file an eNOI for jobs if the new
location is in a new lease block, if jobs are performed for the same designated operator.
Change 3. Operators who filed under the previous permit have an additional 30 days to submit
eNOI, if the system is unavailable during the 60 day renewal period. These operators are covered
under the reissued permit for up to 90 days. The industry requested that EPA extend the timeframe in
which NOIs, covered under the previous permit, must be submitted to retain coverage under the new
permit in the event that the system is unavailable. The industry noted that the system was unavailable
during the last permit reissuance. EPA expects that the system will be available upon permit issuance but
does recognize that there have been periods in the past when it has been unavailable, as a result the final
permit includes an additional 30 days to submit eNOIs, to retain coverage upon reissuance, if the system
is available during the 60 day renewal period.
Change 4. Only new operators, not covered under the previous permit, can submit temporary NOIs
when system is unavailable. Due date and coverage for temporary NOI extended 14 days, after the
system becomes available, if the system remains unavailable after 14 days. The industry requested
that the temporary NOI coverage be extended an additional 14 days, after the system becomes available if
the system is down for more than a period of 14 days. EPA recognizes that there is a potential for the
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system to be down for an extended period of time and therefore modified the final permit to grant an
additional 14 days of coverage to submit an eNOI, when the system is down for more than 14 days, and a
temporary NOI has been submitted. In addition, the intent of temporary NOI was to allow new
permittees/operators to gain coverage in the event that the system is unavailable. Because current
permittees/operators have likely already filed an eNOI in the previous permit term, EPA believes that
temporary NOIs are only necessary for new dischargers and has updated the final permit as such.
Change 5. Removed continuous monitoring language from cooling water intake requirements. In
the July 22, 2022, proposal, EPA included language in regard to Cooling Water Intake that included the
word continuous. The industry commented that continuous intake flow velocity monitoring would require
possibly significant upgrades to existing intake flow velocity monitoring systems including routing of
signals to process computers for automatic logging. Monitoring frequencies allow permittees to manually
log the intake flow velocity if continuous monitoring systems are not feasible. EPA recognizes this
challenge but also notes that the intent of the language added was not to change Cooling Water Intake
velocity monitoring frequencies, and as such has updated the final permit with the word "continuous"
removed in regard to velocity monitoring.
Change 6. Removed the additional requirements for a signed agreement from transfers. The
proposed permit included additional requirements when performing transfers and mergers, which required
a signed agreement along with other additional information to enhance compliance. The industry
commented that this requirement would create an unnecessary burden on the regulated community
because the information is duplicative of NOI information, and proposed changes to the language. While
EPA recognizes that some of the information is redundant, the information required in the permit is
integral to determining liability in instances when mergers occur. The final permit removed the additional
requirements for a signed agreement for transfers but retained these requirements for mergers. Language
was also updated to reflect that NOT must be filed within 60 days of relinquishing operational control
because EPA recognizes that operators/permittees do not have control over when other companies submit
their NOI.
Change 7. Flow rate monitoring for Well Treatment Fluids, Completion Fluids, and Workover
Fluids (TCW Fluids). In the permit proposal, EPA included acute WET limits for TCW discharges.
Industry requested EPA provide clarity on the calculation of critical dilutions for TCW dischargers for
WET purposes. As a response, and to provide clarity on critical dilutions, EPA added daily flow
monitoring requirements, when discharging, for TCW fluids.
Change 8. Characteristic Assessment requirements for Well Treatment Fluids, Completion Fluids,
and Workover Fluids have been removed. Industry commented that the Characteristic Assessment
requirements retained from the 2017 permit were intended to apply to the industry-wide TCW fluid
toxicity study, or individual studies for those operators that chose not to participate in the industry study.
EPA recognizes that the study has concluded (and has included WET limits and monitoring for these
discharges as a result) and that this information is maintained by operators and can be made available
upon request, therefore the Characteristic Assessment requirements for TCW Fluids have been removed
from the final permit.
Change 9. Added language to Sanitary Waste language to ensure that all limits are complied with in
the event the Marine Sanitation Device is not properly operating or not operating. Bureau of Safety
and Environmental Enforcement (BSEE) provided comments on MSD permit requirements specifying
that the permit should clarify that DMRs are required when the system is not operating or not properly
operating. EPA recognizes that it is a requirement to do so, and as a result, to provide permit clarity,
12
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added language to the final permit to specify that limitations and prohibitions apply to MSDs, when not
operating or not properly operating, and directs permittees to submit corresponding DMRs and keep
records when systems are down.
Change 10. Cooling water intake structure operation for New Fixed Facilities that Employ Sea
Chests as Intake Structures and New Fixed Facilities that do not employ sea chests as intake
structures require development, and implementation of operation and maintenance plans, with
reporting requirements for numeric exceedances. Per the fact sheet for the proposed permit, EPAs
intent was to add development, and implementation of operation and maintenance plans, with reporting
requirements for numeric exceedances, to all facilities subject to cooling water intake requirements to
enhance compliance with Cooling Water Intake requirements. EPA received various comments on this
language but has retained the language in the final permit and also corrected a typographical error that
excluded some facilities from these requirements. As a result, the final permit applies these requirements
to all facilities subject to 316(b).
Change 11. All facilities are subject to monitoring requirements if they discharged during said
monitoring period, regardless of whether the discharge lasted the full period. EPA received a
comment that the requirements in the proposed permit that were specific to MODUs was unclear. To
provide clarity in the final permit, EPA updated the language in this section to clarify that all facilities are
subject to monitoring requirements if they discharged during said monitoring period, regardless of
whether the discharge lasted the full period.
Change 12. Methods and/or calculations for estimated flow must be documented. Comments were
received from BSEE, on methods of estimation of flow. EPA recognizes that while the permit does not
specify any one method to estimate flow, EPA does provide a handbook (Handbook for Sampling and
Sample Preservation of Water and Wastewater and the NPDES Compliance Flow Measurement Manual)
that includes acceptable methods. However, EPA does recognize the value in knowing methods of flow
estimation per permittee. As a result, the final permit includes requirements for permittees to document
methods/calculations.
Change 13. Sample type for oil and grease is grab or composite. Comments were received from
BSEE, in regard to oil and grease sampling methods. EPA reviewed method 1664A (which includes
either grab or an average or four or more grab samples, individual analyzed and averaged or manually
composited prior to analysis) and as a result included the composite method in the final permit as a
sampling method for oil and grease.
Change 14. The use of other disinfection technologies, including, but not limited to, bio-membrane
filtration and ultra-violet light are allowed as substitutes for systems that use chlorine, provided
that the MSD is approved by the U.S. Coast Guard and results in equivalent or improved
disinfection of the Sanitary Waste stream to that considered in the ELG. TRC monitoring is not
required for alternative MSDs that do not use chlorine, when the system is not properly operating
or not operating, unless a chlorine based product is used as a backup disinfectant. EPA received
comments on disinfection methods for MSDs, which stated that many MSDs employ disinfection
methods, other than chlorine. EPA recognizes that the U.S. Coast Guard approves MSDs that use these
many alternative methods and as a result has authorized these MSDs to be used by the permit, as long as
they are approved by the Coast Guard and in addition has waived any sampling requirements for chlorine
when the system does not use chlorine, unless chlorine is used as a backup disinfectant.
13
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Change 15. Operators must flush and capture the materials contained in pipelines, umbilicals, and
other equipment prior to disconnection. No releases or discharges of fluid from pipelines,
umbilicals, and/or other equipment that have not been fully flushed prior to being disconnected or
cut from the facility are authorized under this NPDES permit. EPA received comment from BSEE on
decommissioning/abandonment activities that requested that pipelines and umbilicals be flushed, and
material captured prior to disconnection, as such releases are not covered by the permit. EPA recognizes
that it is important that pipelines be flushed before decommissioning to prevent leaking of fluids during
specified operations and as a result included these requirements in the permit.
Change 16. Calculation for WET critical dilutions and testing frequencies for Produced Water is
based on calendar year. The proposed permit included a calculation of flow, which would base the
critical dilution and frequency of WET testing on a 12 month period. Through comments, industry
requested that 12 months be replaced with calendar year to prevent misinterpretations and that the flow be
analyzed at the end of the calendar year, in addition. EPA agreed with the changes to provide clarity to
operators/permittees when determining WET critical dilutions and frequencies.
Change 17. Waiver for the minimum number of samples to be collected for WET tests, should the
effluent cease discharging for Produced Water. Comments were received stating that some discharges
last less than 24 hours, which would make the requirement to have a minimum of three samples for WET
testing for Produced Water difficult to achieve. EPA understands that discharges are not always
continuous. As a result, the final permit includes language that allows a single grab sample to be
acceptable, in the case the effluent ceases to discharge abruptly, and the test has been initiated as long as
the 24 hour period is representative of the discharge throughout the testing period.
Change 18. For Treatment, Completion, and Workover discharges, acute WET results can be
derived from a chronic WET test. EPA received various comments requesting that the permit be
modified to allow one sample to accommodate for both chronic and acute tests for TCW discharges, to
reduce complexity and provide efficiency while still being technically appropriate. Industry also
commented that increasing the number of samples would cause increased transport and laboratory waste
disposals. EPA recognizes these challenges and as a result, the final permit was modified to allow one
sample to accommodate both 48-hour acute testing and 7-day chronic testing.
Change 19. Compliance schedule for WET acute limits related to Treatment, Completion, and
Workover discharges and sample holding time of 72 hours. An acute WET limit was added to the
proposed permit. The industry requested a 2 year compliance period, through comments, stating that they
needed time to determine how to implement the new requirement. The compliance period would also allot
for time to train new personnel, planning, identify impacts to laboratories, and install necessary systems.
EPA understand the challenges associated with including the new limit in the permit and as a result,
modified the final permit to include a two year compliance period for acute WET testing for TCW wastes.
Change 20. No approved Alternative Test Procedure (ATP) for WET, however they can be
requested at any time following 40 CFR 136.5. EPA received comments from the industry that the
language in the previous permit barred them from seeking alternative test procedures for WET, as the
permit stated no alternative test procedures are authorized. To clarify, that the industry can request an
ATP through procedures specified in the regulations, the final permit language has been updated to reflect
this.
Change 21. 72 hour hold time for WET samples for Chemically Treated Miscellaneous Discharges.
EPA received several comments that holding times were unclear, in addition to comments explaining the
14
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logistical complexities, including increased vessel and helicopter trips, and safety risks of meeting a 36
hour hold time. The proposed permit had sample holding times of 36 hours but up to 72 if required for
TCW Fluids and Chemically Treated Miscellaneous Discharges. EPA understands the increased risks and
complexities with meeting a 36 hour hold time for WET testing for these specified discharges and as a
result the final permit allots for a 72 hour hold time for WET samples for TCW Fluids and Chemically
Treated Miscellaneous Discharges.
Change 22. For Chemically Treated Miscellaneous Discharges, non-continuous discharges are
discharges that occur less than or equal to once per week and last less than 24 hours. These
discharges shall be monitored once per discharge. EPA received comments asking for clarity on
continuous and non-continuous discharges in relation to Chemically Treated Miscellaneous Discharges.
EPA recognizes that this portion of the permit was unclear, which could prevent operators/permittees
from correctly determining toxicity testing frequency, as it is a function of duration of discharge for these
discharges. As a result, the final permit provides clarification that non-continuous discharges are
discharges that occur less than or equal to once per week and lasts less than 24 hours and shall be
monitored once per discharge.
Change 23. State general permit or state individual permit may be required in addition to
authorization under this permit. In a letter from Texas Commission on Environmental Quality (TCEQ),
dated October 11, 2022, in regards to Texas Coastal Management Plan Consistency Determination for
Proposed EPA Reissuance ofNPDES Permit No. GMG290000, TCEQ stated "To ensure protection of
coastal natural resource areas and compliance with Texas Surface Water Quality Standards (30 TAC
Chapter 307) that apply to surface waters in the state, including the Gulf of Mexico inside the territorial
limits of the state, the TCEQ requires that all facilities with discharges to state waters authorized under
proposed NPDES permit no. GMG290000 must also seek coverage under TCEQ state general permit no.
WQG280000, once issued, or an individual permit if authorization under the general permit is not
feasible." As a result, EPA has added language to the final permit to specify that a state general or
individual permit may also be required, independent from this general permit, for authorization.
Change 24. Defines decommissioning and subsea cleaning fluid. Commenters requested that these
definitions be added to the final permit to provide clarity of discharges and operations. As a result, the
final permit includes the aforementioned definitions.
Change 25. 7-day chronic toxicity requirements for Well Treatment Fluids, Completion Fluids, and
Workover Fluids has been moved from limitations to monitoring section, to provide clarity that
chronic is monitoring only. The proposed permit included acute WET limits for TCW discharges and
chronic monitoring requirements, however EPA mistakenly placed both of these requirements under
limitations for TCW fluids. To provide clarity that acute WET limits apply, and only chronic monitoring
applies for these discharges, EPA has moved the chronic requirements from the limitations section to the
monitoring section for TCW discharges.
Change 26. Free oil language has been updated to reference DMRs and twenty-four hour reporting
requirements. In the proposed permit, EPA added a requirement for sheens to be reported via a new 24-
hour reporting portal, in addition to DMR requirements. The industry commented that it was unclear that
24-hour reporting was required for sheens. As a result, EPA modified sheen the language for free oil to
reference both DMRs and the 24-hour reporting language in the permit.
Change 27. Part I.C. reflects Other Limitations, Prohibitions and Discharges not Authorized.
Moved Limitations on Coverage section in Part I.A.I to Part I.C for Prohibitions and Discharges
15
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Not Authorized. EPA received comments on Part I.A.I and I.C of the permit. To provide clarity EPA has
updated the title of Part I.C. to accurately categorize the context of this section of this permit. In addition,
EPA has also moved limitations on coverage section in Part I.A. 1 to Part I.C for prohibitions for clarity.
Change 28. Permit does not authorize radioactive materials that are under the jurisdiction of the
NRC. EPA received comments on this prohibition. In addition, requirements were clarified with the NRC
in regard to Radioactive Materials. As a result, language was modified in the final permit to clarify that
this permit does not authorize radioactive materials that are under the jurisdiction of the NRC.
Change 29. Miscellaneous Discharges of Water Which Have Been Chemically Treated includes
discharges from well operations other than those covered by other sections of Part I.B of the
permit. The industry commented that seawater and fresh water used for fluid displacement in well
operations is drawn from chemically treated and uncontaminated sources. The chemically treated water
sources are the same as, or similar to, those sources used for water released during training of personnel in
fire protection, ballast water, once through non-contact cooling water, water used as piping or equipment
preservation fluids, and water used during Dual Gradient Drilling. The change provides clarity and would
be more inclusive of current operations in industry. EPA recognizes that adding well operations other than
those covered in Part I.B. of the permit will be more inclusive of current operations and provide clarity
and as a result, added well operations, other than those covered by other sections, of the permit to these
discharges.
Change 30. Corrections to the Permit Summary Table. Table is for reference only. Comments were
received requesting that the Permit Summary Table be updated to reflect current permit limitations.
Corrections were made to the Permit Summary Table to accurately reflect permit limitations. Statement
"For Reference Only: In the event of a discrepancy, the language in the text of the permit is the
enforceable condition.)" was added.
Change 31. Corrected data for Discharge Monitoring Reports (DMRs) and Other Reports must be
submitted as soon as the error has been identified but no later than the following quarter.
Submittal of corrected data does not excuse any permit violation. EPA received comments requesting
a definitive timeline be provided for submitting corrected DMRs and Other Reports. As a result, EPA
included additional language to address this issue and also specified that it is a violation of the permit to
submit no discharge reports when discharge has occurred.
Change 32. If Offshore 24-Hour Reporting Application Portal is not available, an email shall be
sent within 24 hours of occurrence of specified violations and electronic report shall be submitted
within 14 days of the system becoming available. In the comments, the industry requested a secondary
method if submitting these reports in the event that the online system is available. EPA recognizes that
these challenges and as a result included the aforementioned language.
Change 33. A facility map that delineates authorized discharge locations and type must be
submitted, as an attachment, when filing the eNOI. BSEE requested, in comments, that each
discharge point for each limit set be delineated. To provide clarity, the final permit has been updated to
require permittees/operators to submit a facility map as an attachment, when filing the NOI, that
delineates authorized discharge locations and discharge type.
Change 34. Updated language to provide clarity that timely updates to "CDX" are required, in lieu
of "eNOI". Language was updated to clarify where updated shall be provided.
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Change 35. Numeric exceedances of maximum through-screen design intake velocity and dates
must also be included on DMRs, for all new facilities required to comply with intake structure
monitoring requirements. To provide clarity on Cooling Water Intake reporting, language has been
updated to add that exceedances and dates must be reported on DMRs.
Change 36. Provided definition of Mobile Offshore Drilling Unit (MODU) has been removed from
the permit because it does not exist in the Code of Federal Regulations. Part I.A.2 has been updated
to provide examples of MODUs. Because the definition provided in the draft permit did not exist in the
Code of Federal Regulations, the definition was removed from the permit.
Change 37. Civil and administrative penalty amounts have been updated to reflect updated
statutory amounts. Regulatory amounts were updated to account for inflation. Corresponding changes
were made to the permit.
Change 38. Once a month temperature monitoring for produced water. Center for Biological
Diversity commented that EPA should set a temperature limit for produced water and other discharges.
To collect data on produced water discharges, produced water monitoring for temperature has been
included in the final permit at a frequency of once per month. Temperature monitoring is relatively
inexpensive and simple.
VI. Summary of Significant Changes from the Current (2017) Permit
The following Table provides a quick comparison of the 2017 permit with this 2022 permit.
Subject
2017 Permit Conditions
Changes for 2022 Permit
Rationale
for Change
NOIs
7 day temporary NOI coverage.
eNOI must be submitted when
system becomes available.
Temporary NOI can be provided
by mail.
14 day temporary NOI coverage and
for submission of eNOI for new
operators only. An additional 14
days of coverage and to submit
eNOI, from the time the system is
available again, when the system is
still down after 14 days. Temporary
NOI can be provided by mail or
email.
See Section
V. Change 4
above
NOIs
Operators who filed eNOIs under
the previous permit, issued on
September 28, 2012, will be
authorized to discharge by this
reissued permit without submittal
of an NOI up to April 1, 2018.
60 day renewal period for operators
who filed eNOIs under the previous
permit. Should the eNOI system not
be available during this 60 day
period, operators may submit the
eNOI the latter of 60 days after the
effective date of the permit or 30
days from the date the system was
restored. Permittees/operators are
covered by the reissued permit
during this period for up to 90 days.
See Section
V. Change 3
above
NOIs
An eNOI filed for a drilling vessel
is valid for different drilling jobs
within the same
An eNOI filed for a Mobile Offshore
Drilling Unit or vessel is valid for
different well jobs within the same
See Section
V. Change 2
above
17
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lease block from the originally
filed location if drilling jobs are
performed for the same
designated operator.
lease block, indicated on the eNOI, if
jobs are performed for the same
designated operator. A separate
eNOI is required for well jobs not
within the same lease block, and/or
if the Mobile Offshore Drilling Unit
or vessel moves to a new lease
block.
NOIs
A facility means either an
exploratory facility, a
development facility, or a
production facility as
defined in Part II.G of the permit.
All well heads and infrastructures
connected to the facility shall be
considered parts of the host
facility.
A facility means either an
exploratory facility, a development
facility, or a production facility as
defined in Part II.G of the permit.
All well heads, pipelines, jumpers
and associated and infrastructures
connected to the facility shall be
considered parts of the host facility,
even where such infrastructure
crosses lease block boundaries.
See Section
V. Change 1
above
NOIs: additional
information
N/A
A facility map that delineates
authorized discharge locations and
type must be submitted, as an
attachment, when filing the eNOI.
See Section
V. Change
33 above
Decommissioning/
Abandonment
Prohibitions
N/A
Operators must flush and capture the
materials contained in pipelines,
umbilicals, and other equipment
prior to disconnection. No releases
or discharges of fluid from pipelines,
umbilicals, and/or other equipment
that have not been fully flushed prior
to being disconnected or cut from the
facility are authorized under this
NPDES permit.
See Section
V. Change
15 above
Operations
Covered and
Discharges
Authorized
N/A
Authorization under a state general
or individual permit may also be
required to discharge.
See Section
V. Change
23 above
Operations
Covered and
Discharges
Authorized
N/A
Lists Operations Covered and
Discharges Authorized included
limitations on coverage which
references section I.C which
includes Other Limitations,
Prohibitions and Discharges not
Authorized.
See Section
V. Change
27 above
NOI
N/A
Permittees are required to make
timely updates to the CDX system.
Any change in name, location,
address, contact or contact
See
discussion
below
18
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information must be updated within
30 days of the change.
Termination of
NPDES Coverage
In the case of temporary
operations such as hydrostatic
testing, well or facility
abandonment or any other
contractual or legal requirement,
the NOT shall be submitted within
one year of termination of
operations.
In the case of temporary operations
such as hydrostatic testing, well or
facility decommissioning/
abandonment or any other
contractual or legal requirement, the
NOT shall be submitted within one
year of termination of operations.
See Section
V. Change
15 above
Transfers &
Mergers
During the initial term of permit:
The new operator shall submit an
NOI prior to taking operational
control and the old operator shall
submit a NOT within 60 days of
receiving confirmation that the
new permittee has submitted the
NOI. During any "administratively
continued" term of the permit
following the indicated expiration
date: The new operator shall
submit an NOI at least 30 days
prior to taking operational control
and the old operator shall submit a
NOT within 60 days of
receiving confirmation that the
new permittee has submitted the
NOI. The new operator shall
submit a written agreement
between the new and old
permittees concerning the date of
the transfer of permit
responsibility, coverage, and
liability between themselves,
report number of days with sheens
observed.
During the initial term of permit:
The new or surviving operator shall
submit an NOI prior to taking
operational control and the old
operator shall submit a NOT (for all
lease areas/blocks as well as their
NPDES permit number) within 60
days of relinquishing operational
control. The old operator shall
submit final DMRs within 60 days of
NOT. Companies involved in a
merger must also submit a written
and signed agreement between the
companies identifying: the names of
the two offshore companies and their
assigned NPDES permit number; the
agreement between the two
companies for the merger; the
effective date of the merger; the
lease area(s)/block(s) involved in the
merger; the surviving company
name; the surviving NPDES permit
number; and liability. This letter can
be emailed to the Offshore Specialist
or sent to the address below. During
any "administratively continued"
term of the permit following the
indicated expiration date: The new
operator shall submit an NOI at least
30 days prior to taking operational
control and the old operator shall
submit a NOT within 60 days of
relinquishing operational control.
The new operator shall submit a
written agreement between the new
and old permittees concerning the
date of the merger of permit
responsibility, coverage, and
liability. NOTE: Each company
See Section
V. Change 6
above and
discussion
below
19
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must collect and report their own
samples. Samples from a company
transferring coverage cannot be used
by the receiving company.
Continuation of
Coverage for
Existing Operators
After the Permit
Expires
N/A
If the permit is not reissued or
replaced prior to the expiration date,
it will be administratively continued
in accordance with section 558(c) of
the Administrative Procedure Act
(see 40 CFR 122.6).
See
discussion
below
Free Oil
Limitations
If a sheen is observed at other
times, in addition to the required
daily monitoring, it must be
recorded. The number of days a
sheen is observed must be
Recorded.
The total number of days a sheen is
observed must be recorded and
reported on DMRs and to the
twenty-four hour noncompliance
portal.
See Section
V. Change
26 above
Cooling water
Intake Structure
Operations
Requirements
The cooling water intake structure
must be designed and constructed
so that the maximum through-
screen design intake velocity is 0.5
ft/s; The operator must minimize
impingement mortality of fish and
shellfish
through cooling water intake
design and construction
technologies or operational
measures for New Fixed Facilities
with See Chests and non-Fixed
Facilities. The operator must
minimize impingement mortality
of fish and shellfish and minimize
entrainment of entrainable life
stages of fish and shellfish through
the use of cooling water intake
design and construction
technologies or operational
measures for New Fixed Facilities
without Sea Chests
The cooling water intake structure(s)
must be designed, constructed,
operated, and maintained so that the
maximum through-screen design
intake velocity shall not exceed 0.5
ft/s; The permittee must develop and
implement an Operation and
Maintenance plan to minimize
impingement mortality of fish and
shellfish through use of cooling
water intake design and construction
technologies or operational
measures.
See Section
V. Change
10 above.
Cooling Water
Intake Reporting
Requirements
Intake velocity monitoring:
Number of days on which the
maximum intake velocity
is greater than 0.5 ft/s for each
month
Intake velocity monitoring: Identify
the dates on which the maximum
intake velocity is greater than 0.5 ft/s
for each month and include the
numeric exceedance for each date
identified. Exceedances and dates
must also be reported on DMRs.
See
discussion
below and
See Section
V. Change
35 above
Monitoring and
Records:
Reporting during
periods of natural
N/A
NODI codes for various
disasters/incidents. Operators have
30 days from the incident to submit
DMRs or other required reporting.
See
discussion
below
20
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disasters,
environmental
conditions, or
weather related
incidents
Requirements for
Monitoring when
Discharging for
Less than a Full
Monitoring Period
N/A
Sample(s) must be collected and
analyzed to meet annual, quarterly,
monthly, weekly, and daily
monitoring requirements even if
discharging for less than that full
monitoring period, provided
discharges occur at any time during
that monitoring period. If no
discharges occurred during the
monitoring period, reporting "No
Discharge" on the DMR satisfies this
requirement
See
discussion
below and
See Section
V. Change
11 above
Radioactive
Materials under
jurisdiction of
NRC
N/A
Discharge of radioactive materials
under the jurisdiction of the NRC are
not independently authorized by this
permit.
See
discussion
below and
See Section
V. Change
28 above
Twenty-Four
Hour Reporting
Requirements
Noncompliances which endanger
health or environment shall be
reported to
R6GENPERMIT@epa.gov within
24 hours from the time the
permittee becomes
aware of the circumstances.
Noncompliances which endanger
health or environment shall be
reported to the Offshore 24-Hour
Reporting Application Portal. If
system is unavailable, an email
should be sent to the offshore
coordinator and report must be
submitted to online portal within 14
days of the system becoming
available again
See
discussion
below and
See Section
V. Change
32 above.
Produced Water:
Toxicity
Flow for the purpose of
calculating a critical dilution (the
toxicity limit) and the toxicity
testing frequency, analyzed on a
quarterly basis. Toxicity data
submitted per quarterly. Minimum
of one sample shall be collected.
Flow for the purpose of calculating a
critical dilution (the toxicity limit)
and the toxicity testing frequency,
analyzed per calendar year at the end
of the year. Toxicity data submitted
per quarterly, but per month. A
minimum of three samples shall be
collected as grab or composite.
See
discussion
below
Produced Water:
Temperature
Monitoring
N/A
Once/Month
See Section
V. Change
38 above.
WET testing
Invertebrate species for WET
testing: Mysidopsis bahia
Invertebrate species for WET
testing: Americamysis bahia
See
discussion
below
21
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Well Treatment,
Completion and
Workover Fluids:
Toxicity
Industry Wide Study Requirement
Acute WET limitations and two year
compliance period. Chronic WET
monitoring requirements.
See
discussion
below
Definitions
No definitions for Operator,
barrel, manned facility, floating
offshore facility, discharge of
pollutant, decommissioning and
subsea fluids
Produced Water" means the water
(brine) brought up from the
hydrocarbon-bearing strata during
the extraction of oil and gas, and
can include formation water,
injection water, and any chemicals
added downhole or during the
oil/water separation process.
"Workover Fluids" mean salt
solutions, weighted brines,
polymers, and other specialty
additives used in a producing well
to allow safe repair and
maintenance or abandonment
procedures. High solids drilling
fluids used during workover
operations are not considered
workover fluids by definition and
therefore must meet drilling fluid
effluent limitations before
discharge may occur. Packer
fluids, low solids fluids between
the packer, production string and
well casing, are considered to be
workover fluids and must meet
only the effluent requirements
imposed on workover fluids.
Operator, barrel, manned facility,
floating offshore facility, discharge
of pollutant, decommissioning and
subsea fluids definitions are in the
final permit.
"Produced Water" means the water
(brine) brought up from the
hydrocarbon-bearing strata during
the extraction of oil and gas, and can
include formation water, injection
water, and any chemicals added
downhole or during the oil/water
separation process. Note for the
purposes of this permit Produced
Water is interpreted to include
oil/gas/water separation processes.
"Workover Fluids" mean salt
solutions, weighted brines, polymers,
and other specialty additives used in
a producing well, associated
producing well infrastructure (e.g.,
flowlines, manifolds), or latched up
workover system to allow safe repair
and maintenance or abandonment
procedures. High solids drilling
fluids used during workover
operations are not considered
workover fluids by definition and
therefore must meet drilling fluid
effluent limitations before discharge
may occur. Packer fluids, low solids
fluids between the packer,
production string and well casing,
are considered to be workover fluids
and must meet only the effluent
requirements imposed on workover
fluids.
See
discussion
below.
All Sanitary
Waste Facilities
The operator is required to
demonstrate proper operation of
MSD via U.S. Coast Guard
approval, annual inspections,
Class/Flag State inspections and/or
the International Sewage Pollution
Prevention Certificate (ISPPC)
and maintenance
The operator is required to
demonstrate proper operation of
MSD via U.S. Coast Guard approval,
annual inspections, Class/Flag State
inspections and/or the International
Sewage Pollution Prevention
Certificate (ISPPC) and maintenance
logs/records. Failure to comply must
22
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logs/records.
be included in a non-compliance
report to EPA.
Sanitary Waste
(Facilities
Continuously
Manned for 30 or
more consecutive
days by 10 or
More Persons)
Chlorine only for disinfection.
TRC minimum of 1 mg/1.
Equivalent Disinfection - Other
Technologies. The use of other
disinfection technologies, including,
but not limited to, bio-membrane
filtration and ultra-violet light are
allowed as substitutes for systems
that use chlorine, provided that the
MSD is approved by the U.S. Coast
Guard and results in equivalent or
improved disinfection of the sanitary
waste stream to that considered in
the ELG. For alternative MSDs that
do not use chlorine, monitoring for
TRC limitations is not required when
the system is not properly operating
or not operating.
See Section
V. Change
14 above
Oil and Grease
Sampling
The sample type for all oil and
grease monitoring shall be grab.
The sample type for all oil and
grease monitoring shall be grab or a
composite which consists of the
arithmetic average of the results of
four (4) or more grab samples
collected at even intervals during a
period of 24-hours or less.
See Section
V. Change
13 above
Miscellaneous
Discharges of
Water Which
Have Been
Chemically
Treated
Excess water which permits the
continuous operation of fire
control and utility lift pumps,
Excess water from pressure
maintenance and secondary
recovery projects, Water released
during training of personnel in fire
protection, Water used to pressure
test new and existing piping and
pipelines, Ballast water, Once
through non-contact cooling
water, Water used as piping or
equipment preservation fluids, and
Water used during Dual Gradient
Drilling
Added Well operations other than
those covered by other sections of
Part I.B of the permit to
Miscellaneous Discharges of Water
Which Have Been Chemically
Treated.
See Section
V. Change
29 above
Miscellaneous
Discharges of
Water Which
Have Been
Chemically
Treated: Toxicity
In cases where the discharge point
for hydrostatic test water is
subsea, such as the subsea end of a
pipeline, and it is impractical to
collect a sample at the discharge
point, operators may collect a
sample for this monitoring
requirement prior to use of the
fluid.
Replaced hydrostatic test water with
chemically treated miscellaneous
seawater or freshwater.
See
discussion
below
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Miscellaneous
Discharges of
Water Which
Have Been
Chemically
Treated: Toxicity
Required frequency of testing for
continuous discharges shall be
determined as follows: Discharge
Rate 0 - 499 bbl/day - once/year,
500 - 4,599 bbl/day - once/quarter
4,600 bbl/day and above once/
month. Intermittent or batch
discharges shall be monitored
once per discharge but are
required to be monitored no more
frequently than the corresponding
frequencies shown above for
continuous discharges.
The required frequency of testing for
continuous discharges shall be
determined as follows:
Discharge Rate 0 - 499 bbl/day -
once/year, 500 - 4,599 bbl/day -
once/quarter, 4,600 bbl/day and
above - once/month. Non-
continuous discharges (occur less
than or equal to once per week and
lasts less than 24 hours) shall be
monitored once per discharge.
See Section
V. Change
22 above
Miscellaneous
Discharges of
Water Which
Have Been
Chemically
Treated: Toxicity
Sample holding time 36 hours, up
to 72 hours.
Sample holding time 72 hours.
See Section
V. Change
21 above
Flow
Measurement
Appropriate flow measurement
devices and methods consistent
with accepted scientific practices
shall be selected and used to
ensure the accuracy and reliability
of measurements of the volume of
monitored discharges.
Appropriate flow measurement
devices and methods consistent with
accepted scientific practices shall be
selected and used to ensure the
accuracy and reliability of
measurements of the volume of
monitored discharges. Flow
estimation methods and/or
calculations must be documented.
See Section
V. Change
12 above
Permit Summary
Table
Corrections were made to the table
to accurately reflect limitations.
See Section
V. Change
30 above
Reporting
requirements for
Discharge
Monitoring
Reports (DMRs)
and Other Reports
N/A
Corrected data for Discharge
Monitoring Reports (DMRs) and
Other Reports must be submitted as
soon as the error has been identified
but no later than the following
quarter. Submittal of corrected data
does not excuse any permit violation.
See Section
V. Change
31 above
Civil and
Administrative
Penalties
Civil Penalties
The Act provides that any person
who violates a permit condition
implementing sections 301, 302,
306, 307, 308, 318, or 405 of the
Act is subject to a civil penalty not
to exceed $64,618. $52,414 per
day for each violation.
Administrative Penalties
Class I Penalty
Civil Penalties
The Act provides that any person
who violates a permit condition
implementing sections 301, 302,
306, 307, 308, 318, or 405 of the Act
is subject to a civil penalty not to
exceed $64,618 per day for each
violation.
Administrative Penalties
Class I Penalty
See Section
V. Change
37 above
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Not to exceed $20,965 per
violation nor shall the maximum
amount exceed $52,414.
Class II penalty
Not to exceed $20,965 per day for
each day during which the
violation continues nor shall the
maximum amount exceed
$262,066.
Not to exceed $25,847 per violation
nor shall the maximum amount
exceed $64,618.
Class II penalty
Not to exceed $25,847 per day for
each day during which the violation
continues nor shall the maximum
amount exceed $323,081.
Permittees are required to make timely updates to the CDX system. Any change in name, location,
address, contact or contact information must be updated within 30 days of the change. Language has
been added to the permit to ensure that system maintains accurate contact information.
Continuation of Coverage for Existing Operators After the Permit Expires. Previous permit does not
provide language for coverage in the event the permit expires before re-issuance. Standard Administrative
Continuance language has been added to the renewal. This section also clarifies for permittees that new
operators are not eligible for coverage during any administrative continuance period and that existing
permittees may not submit new NOIs during this period.
Transfers and Mergers. The previous permit did not clarify the manner in which to execute a transfers
and mergers, which are separate processes. In the renewal, language has been provided to clarify that a
merger requires a signed agreement and provides detail on the information that should be provided in a
letter to EPA. In addition, language has been added to specify to that each company must collect and
report their own samples.
Well Treatment Fluids, Completion Fluids, and Workover Fluids: Toxicity. As a result of the
industry-wide toxicity study that was completed as a requirement of the 2017 permit, EPA removed the
industry wide study alternative and included acute toxicity limits to discharges of Well Treatment,
Completion, and Workover Fluids. Data from the study indicated there is reasonable potential for acute
toxicity stemming from these discharges. Therefore, in accordance with 40 CFR §122.44 (d)(l)(iv), acute
WET limits were included. Chronic toxicity monitoring was also required to assess potential for chronic
effects. A two year compliance period for acute toxicity limits was also added.
Invertebrate species for WET testing: Americamysis bahia. The previous permit did not include the
appropriate invertebrate species for toxicity testing in seawater. As a result, this permit replaced the use of
Mysidopsis bahia with Americamysis bahia, which is the more appropriate invertebrate species that
should be used when conducting toxicity testing in seawater environments.
Produced Water: Toxicity. The final permit analyzes flow on a calendar year basis to provide clarity
and consistency in the flow calculation process. Previous permit required a quarterly determination,
which created confusion. In addition, the renewal permit requires toxicity data to be submitted on a
monthly basis in quarterly reports, regardless of the testing frequency, to allow a space in the DMRto
report data under a fluctuating frequency. The previous permit required a minimum of only one sample
for toxicity testing. The final permit requires a minimum of three samples as grabs or composites, per
method.
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Noncompliances which endanger health or environment shall be reported to the Offshore 24-Hour
Reporting Application Portal. EPA has developed an electronic reporting system for twenty-four hour
reporting which will enhance and streamline reporting. As a result, the permit has been updated to reflect
this change.
Discharge of radioactive materials under the jurisdiction of the NRC are not independently
authorized by this permit. The previous permit did not address the discharge of radionuclides. EPA was
made aware that radioactive materials under the jurisdiction of the Nuclear Regulatory Commission
(NRC), e.g., Iridium-192 and Scandium-46, are being used in small amounts in conjunction with
proppants. EPA does not have authority to authorize discharges of radioactive materials that fall under the
jurisdiction of the NRC. As a result, the final permit added language to clarify that radionuclide
discharges that fall under the jurisdiction of the NRC cannot be authorized by this permit.
Requirements for Monitoring when Discharging for Less than a Full Monitoring Period. In the
previous permit, it was unclear that facilities are required to meet testing requirements during the time
that they are operational, even if the operations are active for less than the full monitoring period. As a
result, language was added to clarify this.
Monitoring and Records: Reporting during periods of natural disasters, environmental conditions,
or weather related incidents. The previous permit did not clarify how and when to report during periods
of natural disasters, environmental conditions, or weather related incidents. The final permit provides
NODI codes to use when reporting these issues and gives operators 30 days from incident to submit
DMR's or other required reporting documents.
Cooling Water Intake Reporting Requirements. The change clarifies reporting requirements for
cooling water intake velocity exceedances and provides enhanced compliance in the final permit.
Exceedances and dates must also be reported on DMRs.
Definitions. Aforementioned definitions were added to enhance compliance and mirror current offshore
operations.
All Sanitary Waste Facilities. Language is included in the final permit to ensure that EPA is made aware
when U.S. Coast Guard requirements are not met. Failure to comply with MSD requirements mentioned
in the permit must be submitted to EPA in a non-compliance report.
Miscellaneous Discharges of Water Which Have Been Chemically Treated: Toxicity. Hydrostatic test
water was replaced with chemically treated miscellaneous seawater or freshwater to allow toxicity
samples to be collected for all subsea fluids under this section. This will simply compliance with toxicity
testing for multiple subsea discharge activities and allow for subsea sampling beyond hydrostatic test
waters.
Section VII. Supplemental Information for Other Statutory and Regulatory
Requirements
State Water Quality Standards and State Certification. The permit does not authorize
discharges to State waters; therefore, the state water quality certification provisions of the Clean
Water Act (CWA or 'the Act') Section 401 do not apply to this proposed action.
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Coastal Zone Management Act. The Environmental Protection Agency determined that
activities authorized by this reissued permit are consistent with the local and state Coastal Zone
Management Plans. Both the Louisiana Department of Natural Resources and Texas
Commissions on Environmental Quality (TCEQ) concurred with the EPA's consistency
determination. TCEQ required "To ensure protection of coastal natural resource areas and
compliance with Texas Surface Water Quality Standards (30 TAC Chapter 307) that apply to
surface waters in the state, including the Gulf of Mexico inside the territorial limits of the state,
the TCEQ requires that all facilities with discharges to state waters authorized under proposed
NPDES permit no. GMG290000 must also seek coverage under TCEQ state general permit no.
WQG280000, once issued, or an individual permit if authorization under the general permit is
not feasible." EPA added language to the final permit to specify that a state general or individual
permit may also be required, individual from this general permit, for authorized.
National Historic Preservation Act. Facilities which adversely affect properties listed or
eligible for listing in the National Register of Historic Places are not authorized to discharge
under this permit.
Oil Spill Requirements. Section 311 of the Clean Water Act, (CWA or the Act), prohibits the
discharge of oil and hazardous materials in harmful quantities. Discharges that are authorized by
NPDES permits are excluded from the provisions of Section 311. However, the permit does not
preclude the institution of legal action or relieve permittees from any responsibilities, liabilities,
or penalties for other, unauthorized discharges of oil and hazardous materials which are covered
by Section 311 of the Act. This permit does not authorize spills or any uncontrolled discharges.
Ocean Discharge Criteria Evaluation. For discharges into waters of the territorial sea,
contiguous zone, or oceans, CWA Section 403(c) requires the EPA to consider guidelines for
determining potential degradation of the marine environment when issuing NPDES permits.
These Ocean Discharge Criteria (40 CFR 125, Subpart M) are intended to "prevent unreasonable
degradation of the marine environment and to authorize imposition of effluent limitations,
including a prohibition of discharge, if necessary, to ensure this goal" (45 FR 65942, October 3,
1980). The EPA Region 6 determined that discharges in compliance with the Outer Continental
Shelf (OCS) general permit would not cause unreasonable degradation of the marine
environment.
Marine Protection, Research, and Sanctuaries Act. The Marine Protection, Research and
Sanctuaries Act (MPRSA) of 1972 regulates the transportation for dumping of materials into
ocean waters and establishes permit programs for ocean dumping. This reissued permit does not
authorize dumping under MPRSA.
In addition to the MPRSA establishes the Marine Sanctuaries Program, implemented by the
National Oceanographic and Atmospheric Administration (NOAA), which requires NOAA to
designate certain ocean waters as marine sanctuaries for the purpose of preserving or restoring
their conservation, recreational, ecological, or aesthetic values. Pursuant to the Marine Protection
and Sanctuaries Act, NOAA has designated the Flower Garden Banks, an area within the
coverage of the OCS general permit, a marine sanctuary. The OCS general permit prohibits
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discharges in areas of biological concern, including marine sanctuaries. The permit authorizes
discharges incidental to oil and gas production from a facility which predates designation of the
Flower Garden Banks National Marine Sanctuary as a marine sanctuary. EPA has previously
worked extensively with NOAA to ensure that authorized discharges are consistent with
regulations governing the National Marine Sanctuary.
National Environmental Policy Act. Pursuant to the National Environmental Policy Act
(NEPA) (42 U.S.C. 4321-4307h), the Council on Environmental Quality's NEPA regulations (40
CFR part 15), and EPA's regulations for implementing NEPA (40 CFR part 6), EPA has
determined that the 2023 reissuance of the OCS General Permit is eligible for a categorical
exclusion requiring documentation under 40 CFR 6.204(a)(l)(iv). This category includes
"actions involving reissuance of a NPDES permit for a new source providing the conclusions of
the original NEPA document are still valid, there will be no degradation of the receiving waters,
and the permit conditions do not change or are more environmentally protective." . In connection
with its oil and gas leasing programs under the Outer Continental Shelf Lands Act, the Bureau of
Ocean Energy Management of the Department of Interior (BOEM) has prepared and published
an environmental impact statement (EIS) on potential impacts of oil and gas operations in the
Central and Western Gulf of Mexico for the 2017 - 2022 period. The analysis and conclusions
regarding the potential environmental impacts, reasonable alternatives, and potential mitigation
included in the EIS are still valid for the 2023 reissuance of the OCS General Permit because the
proposed permit conditions are either the same or more environmentally protective. Actions may
be categorically excluded if the action fits within a category of action that is eligible for
exclusion and the proposed action does not involve any extraordinary circumstances. EPA has
reviewed the proposed action and determined that the 2023 reissuance of the OCS General
Permit does not involve any extraordinary circumstances listed in 6.204(b)(1) through (10).
Magnuson-Stevens Fisheries Conservation and Management Act. The Magnuson-Stevens
Fisheries Conservation and Management Act requires that federal agencies proposing to
authorize actions that may adversely affect essential fish habitat (EFH) consult with the National
Marine Fisheries Service (NMFS). The entire Gulf of Mexico has been designated as EFH. The
EPA prepared an Essential Fish Habitat Assessment Report and determined that the minimal
short-term impacts associated with the permitted NPDES discharges would not result in
substantial adverse effects on EFH or managed species in any life history stage, either immediate
of cumulative, in the project area. NMFS concurred with the EPA's assessment and agreed that
the proposed mitigation measures to be incorporated into the permit will minimize adverse
impacts to EFH or federally managed fisheries species.
Endangered Species Act (ESA). On March 13, 2020, National Marine Fisheries Service issued
an Endangered Species Act Section 7 Biological Opinion on the Federally Regulated Oil and Gas
Program Activities in the Gulf of Mexico. EPA initiated a review with National Marine Fisheries
Service to ensure that all activities are consistent with those described in the Biological Opinion.
The main changes to the permit include new intake structure requirements and more stringent
whole effluent toxicity limits based on sub-lethal effects, in additional to other more stringent
requirements. Since those changes would increase the level of protection, EPA determined that
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reissuance of the permit was not likely to adversely affect any listed threatened or endangered
species or their critical habitat.
By email received by the EPA on August 12, 2022, NMFS concluded that the proposed General
Permit GMG290000 remained within scope of the 2020 biological opinion, associated
appendices and subsequent amendments. NMFS agreed that the activities described in the permit
application are unlikely to result in additional effects beyond those previously considered in the
BiOp.
Paperwork Reduction Act. The information collection required by this permit will reduce
paperwork significantly through implementation of electronic reporting requirements. The EPA
is working on an electronic notice of intent (eNOI) system which will allow applicants to file
their NOIs online. The EPA estimates that it takes 10 to 15 minutes to fill in all information
required by the eNOI for each lease block. It also takes much less time to add, delete, or modify
eNOIs. In addition to the eNOI system, the EPA will incorporate an electronic discharge
monitoring report (NetDMR) requirement into the permit. The time necessary for NetDMR
preparation will be much less than that for paper DMR preparation. Both electronic filing
systems will significantly reduce the mailing costs.
The information collection activities in this permit will be submitted to OMB, see "ICR
Supporting Statement Information Collection Request for National Pollutant Discharge
Elimination System (NPDES) Program (Renewal)' (EPA ICR No. 0229.25, OMB Control No.
2040-0004). The current ICR is approved through April 30, 2023. EPA submitted a timely
renewal ICR to OMB and may continue to collect information under this ICR while the
submission is pending before OMB.
Impact on Small Businesses. EPA analyzed the potential impact of today's permit on small
entities and concludes that this permit reissuance will not have a significant impact on a
substantial number of small entities. As discussed in Section VI. Summary of Significant
Changes from the Current (2012) Permit, all changes from the 2012 permit results in either no or
negligible incremental cost and no or negligible operational and/or economical burdens. In
addition, there are not a substantial number of small entities affected by this permit as EPA
understands that there are few, if any, small businesses that are owners or operators of facilities
subject to this permit. EPA did not conduct a quantitative analysis of impacts for this permit, as
that would only be appropriate if the permit may affect a substantial number of small entities.
Additionally, EPA previously found that the promulgation of the Offshore Subcategory
guidelines on which many of the permit's effluent limitations are based did not have a significant
impact on a substantial number of small entities. (58 FR 12492, 1993). The permit also contains
limits based on CWA 403(c) Ocean Discharge Criteria evaluation, but these limits did not
change from the 2017 permit limits based on that analysis.
Regulatory Flexibility Act. The Regulatory Flexibility Act, 5 U.S.C. 601 et seq, requires that
EPA prepare a regulatory flexibility analysis for regulations that have a significant impact on a
substantial number of small entities. As indicated below, the permit reissuance proposed today is
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not a "rule" subject to the Regulatory Flexibility Act. EPA prepared a regulatory flexibility
analysis, however, on the promulgation of the Offshore Subcategory guidelines on which many
of the permit's effluent limitations are based. That analysis shows that reissuance of this permit
will not have a significant impact on a substantial number of small entities.
Clean Water Act. The Clean Water Act ("CWA") establishes a comprehensive program "to
restore and maintain the chemical, physical, and biological integrity of the Nation's waters." 33
U.S.C. § 1251(a). The CWA also includes the objective of attaining "water quality which
provides for the protection and propagation of fish, shellfish and wildlife and ... recreation in
and on the water." 33 U.S.C. § 1251(a)(2)). To achieve these goals, the CWA requires EPA to
control point source discharges of pollutants to Waters of the United States through the issuance
of National Pollutant Discharge Elimination System ("NPDES") permits.
NPDES permits issued for oil and gas exploration, development, and production discharges are
required under Section 402(a)(1) of the CWA to include conditions for meeting technology-
based effluent limits established under Section 301 and, where applicable, Section 306. Once an
effluent limitations guideline or new source performance standard is promulgated in accordance
with these sections, NPDES permits issued by the NPDES permitting authorities must
incorporate requirements based on such limitations and standards. See 40 CFR 122.44(a)(1).
Effluent limitation guidelines for the Offshore Subcategory of the Oil and Gas Extraction Point
Source Category are found at 40 CFR 435, Subpart A.
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