MEMORANDUM

Tetra Tech, Inc.

10306 Eaton Place, Suite 340

Fairfax, VA 22030

phone 703-385-6000

fax 703-385-6007

TO: Paul Shriner and Lisa Biddle, EPA

FROM: Kelly Meadows

DATE: May 6, 2014

SUBJECT: Applicability of the Existing Facility Rule to Offshore Facilities

The purpose of this memo is to document existing information on the applicability of the final 

existing facility rule on facilities that operate offshore. Examples cited in the rulemaking 

preamble include offshore oil and gas extraction facilities, seafood processing vessels, and 

liquefied natural gas (LNG) terminals.

Summary

In general, offshore facilities are substantially different than those onshore. As a result, the 

technologies available to land-based facilities (and studied by EPA for the rulemaking) are 

generally not available for use at the offshore facilities on a widespread basis. Instead, permitting 

authorities are directed to develop 316(b) permit conditions for these facilities on a best 

professional judgment (BPJ) basis. EPA reached this conclusion in the Phase III rule and has not 

encountered any information that would lead it to revise this conclusion.

Background Information

In developing the Phase I rule, EPA became aware of the possibility that the proposed 316(b) 

regulations for new facilities could apply to offshore industrial facilities, such as offshore oil and 

gas extraction facilities.1 However, in the final Phase I rule, EPA determined that it would 

require additional research and analysis to address these offshore industries and postponed taking 

any action.

“EPA will propose and take final action on regulations for new offshore and 

coastal oil and gas facilities, as defined at 40 CFR 435.10 and 40 CFR 435.40, in 

 

1

See 66 FR 28856, May 25, 2001.
the Phase III section 316(b) rule. EPA is deferring regulation of these facilities 

due to the unique engineering, cost, and economic issues associated with offshore 

and coastal drilling rigs, ships, and platforms.” 66 FR 65311, December 18, 2001.

In the Phase III rule,2EPA established requirements for new offshore oil and gas extraction 

facilities.3EPA did not promulgate any national requirements for new seafood processing vessels 

or LNG terminals.

Existing Offshore Industrial Facilities

However, none of the prior rulemaking phases addressed requirements for existing offshore oil 

and gas extraction facilities, as well as for other existing offshore industry sectors. The existing 

facility rule completes EPA’s assessment of offshore facilities by establishing that offshore 

industrial facilities are subject to 316(b) requirements on a site-specific, BPJ basis.

EPA has received little new information regarding offshore industrial facilities since the Phase 

III rule. As a result, EPA continues to rely upon its findings in the Phase III rule regarding the 

applicability of 316(b) requirements to offshore industrial facilities. Specifically (as discussed 

more below), EPA found that while some types of intake technologies may be viable at certain 

existing offshore facilities, there is substantial variability in the performance, technical 

feasibility, and cost to install these technologies. As a result, EPA has again concluded that no 

national requirements are appropriate. Additionally, EPA found that some existing offshore 

facilities may be operating in far offshore locations, beyond the areas defined as “waters of the 

U.S.”

Attachment A to this memo summarizes EPA’s prior analysis of offshore industrial facilities as a 

way to re-examine the potential applicability to existing facilities.

 

2

See 71 FR 35006, June 16, 2006.

3

See § 125.130.
Attachment A: Prior Analyses of Offshore Industrial Facilities

The text below consists of excerpts from previous EPA documents related to offshore industrial 

facilities. It is intended to provide existing information that influenced EPA’s decision to not 

promulgate any national requirements for existing offshore industrial facilities; the text has not 

been tailored for the final rule. For a complete description of EPA’s prior analysis of offshore 

industrial facilities, refer to the Technical Development Document for the Final Section 316(b) 

Phase III Rule (EPA-821-R-06-003), DCN 9-0004 (or FDMS document ID EPA-HQ-OW-2004-

0002-1542) in the Phase III docket.

1. From the Technical Development Document for the Final Section 316(b) Phase III Rule 

(EPA-821-R-06-003), Chapter 1:

Existing Offshore Oil and Gas Extraction Facilities

Because the lowest co-proposed flow threshold option was 50 MGD, the proposed requirements 

would not apply to existing offshore oil and gas extraction facilities, as there are no existing 

offshore oil and gas extraction facilities with a design intake flow greater than 50 MGD. EPA did 

not propose to regulate existing offshore oil and gas extraction facilities, and decided not to 

establish national categorical requirements for them in the final Phase III rule. Instead, permit 

writers must impose impingement and/ or entrainment controls under Section 316(b) at existing 

offshore oil and gas extraction facilities on a case-by-case basis using their best professional 

judgment.

Liquefied Natural Gas Import Terminals

Based on information in EPA’s rulemaking record, EPA identified only a few existing and new 

liquefied natural gas (LNG) import terminals that withdraw water for cooling purposes. 

Currently, only one existing offshore LNG import terminal meets the scope of the proposed 

Phase III rulemaking for existing facilities (e.g., existing facilities with design intake flows 

greater than 50 MGD, 25% or more of the water intake used for cooling purposes). As there is 

only one existing offshore LNG import terminal potentially within scope of the Phase III 

rulemaking, EPA determined that one facility did not justify a national categorical rulemaking. 

Consequently, EPA decided not to establish national categorical requirements for existing 

offshore LNG import terminals in the final Phase III rule. Based on information in EPA’s 

rulemaking record, EPA identified 11 new offshore LNG import terminals may be built over the 

next decade. However, EPA estimates only three or four of these new offshore LNG import 

terminals will meet the scope of the proposed Phase III rulemaking for new facilities (e.g., new 

facilities with design intake flows greater than 2 MGD, 25% or more of the water intake used for 

cooling purposes). As there are only three or four new offshore LNG import terminal potentially 

within scope of the Phase III rulemaking, EPA determined that this limited number of facilities 

did not justify a national categorical rulemaking. Consequently, EPA decided not to establish 

national categorical requirements for new offshore LNG import terminals in the final Phase III 

rule. Instead of national categorical impingement and entrainment control requirements for 

existing and new offshore LNG import terminals, permit writers must impose impingement 
and/or entrainment controls under Section 316(b) on cooling water intake structures at LNG 

import terminals on a case-by-case basis using their best professional judgment.

Seafood Processing Vessels

Because the lowest proposed flow threshold option for a national categorical rule was 50 MGD, 

the proposed requirements would not have applied to existing seafood processing vessels, as 

there are no known existing seafood processing vessels with a design intake flow greater than 50 

MGD. Seafood processing vessels, like most offshore oil and gas extraction facilities, are mobile 

facilities. However, offshore oil and gas extraction facilities may remain stationary for several 

months to several years before relocating. During this time, aquatic habitats are formed in the 

vicinity of the facility. In contrast, seafood processing vessels do not remain stationary for any

considerable period of time. Additional data available to the Agency indicate that given the 

relatively low cooling water flows used by seafood processing vessels, the propensity for 

reduced intake of fish or debris due to the vessel’s speed in relation to the intake’s orientation 

and intake velocity, and their highly mobile character (significantly more so than offshore oil and 

gas extraction facilities), these vessels are best assessed on case-by-case basis. Further, data 

available to the Agency has not clearly identified available technologies that would reduce 

entrainment for such vessels. EPA did not propose to regulate existing seafood processing 

vessels, and decided not to establish national categorical requirements for them in the final Phase 

III rule. For the same reasons as just mentioned, EPA also did not propose, and decided not to 

establish as part of today's final action, national categorical requirements for new seafood 

processing vessels either. Instead, permit writers must impose impingement and/ or entrainment 

controls under Section 316(b) at seafood processing vessels on a case-by-case basis using their 

best professional judgment.

2. From the Technical Development Document for the Final Section 316(b) Phase III Rule 

(EPA-821-R-06-003), Chapter 2:

II. OFFSHORE INDUSTRIES

EPA considered establishing national requirements for three additional industry groups that have 

been identified as potential large users of cooling water: offshore oil and gas extraction facilities, 

seafood processing vessels, and offshore LNG import terminals. An industry survey was 

developed in 2003 to collect data on offshore oil and gas extraction facilities and seafood 

processing vessels. EPA also collected technical and economic information on existing and new 

offshore LNG import terminals.

Under the final rule, only new offshore oil and gas extraction facilities are subject to 316(b) 

national categorical impingement and entrainment control standards. Existing offshore oil and 

gas extraction facilities are not subject to the national categorical requirements of the final rule. 

EPA’s record shows that existing offshore oil and gas extraction facilities have design intake 

flows less than 50 MGD, therefore none would meet the scope and applicability requirements 

considered for the final regulation. Based on information in EPA’s rulemaking record, EPA 

identified only one existing and three or four new offshore LNG import terminals that meet the 

scope of the proposed Phase III rulemaking for new and existing facilities. As there are only four 
or five offshore LNG import terminals potentially within scope of the Phase III rulemaking, EPA 

determined that this limited number of facilities did not justify a national categorical rulemaking. 

Consequently, EPA decided not to establish 316(b) national categorical impingement and 

entrainment control standards for offshore LNG import terminals. Instead of national categorical 

impingement and entrainment control requirements for existing and new offshore LNG import 

terminals, permit writers must impose impingement and/ or entrainment controls under Section 

316(b) for cooling water intake structures at LNG import terminals on a case-by-case basis using 

their best professional judgment.

3. From the Technical Development Document for the Final Section 316(b) Phase III Rule 

(EPA-821-R-06-003), Chapter 2:

EPA concluded no entrainment technologies were available for existing seafood processing 

vessels.

4. From the Technical Development Document for the Final Section 316(b) Phase III Rule 

(EPA-821-R-06-003), Chapter 7:

INTRODUCTION

Under the final Phase III rule, no existing oil and gas (O&G) extraction facilities are subject to 

national performance standards. NPDES permit writers will continue to develop impingement 

and entrainment control standards for these existing facilities using BPJ on a case-by-case basis 

under authority of Section 316(b) of the Clean Water Act. New offshore oil and gas extraction 

facilities are subject to the final rule, as described in the preamble.

Since the Phase I 316(b) rulemaking, EPA collected technical, engineering, and economic 

information associated with this industry sector. EPA also received information from industry

trade associations to assist its analyses. EPA used this information to assess costs, economic 

impact and unique technical issues associated with various technology-based options available to 

control impingement and entrainment of aquatic organisms, including technology-based options 

available for the sea chest type of cooling water intake structures for new and existing offshore 

oil and gas extraction facilities. EPA used Phase I public comments to evaluate a number of BTA 

options specific to the offshore oil and gas extraction cooling water intake structures in the Phase 

III rulemaking. In the Phase III proposal EPA solicited public comments on its data, 

methodology, and proposed regulatory options for controlling impingement and entrainment of 

aquatic organisms from new and existing offshore oil and gas extraction facilities. After 

reviewing and incorporating public comments on the Phase III proposal, EPA is promulgating 

national impingement and entrainment standards for cooling water intake structures at new 

offshore oil and gas extraction facilities.
5. From the Technical Development Document for the Final Section 316(b) Phase III Rule 

(EPA-821-R-06-003), Chapter 7:

5.0 FINAL TECHNOLOGY OPTIONS IDENTIFIED IN THE PHASE III RULEMAKING

EPA proposed to require impingement and entrainment control requirements for new offshore oil 

and gas extraction facilities in the Phase III 316(b) rulemaking. EPA finds the technology

available as discussed earlier in this chapter and affordable (see the Economic Benefits Analysis 

(EBA)). As stated in the Phase III Notice of Data Availability, EPA analyzed additional data on 

the regions in which offshore oil and gas extraction facilities operate in order to better

characterize the potential for entrainment of ichthyoplankton (planktonic egg and larval life 

stages of fish) by offshore oil and gas extraction facilities. EPA believes these data indicate the 

potential for entrainment and impingement from cooling water intake structures at oil and gas 

facilities operating in offshore regions. While the data did show spatial and temporal variations, 

as well as variability at different depths, the range of ichthyoplankton densities found were 

within the same range seen in coastal and inland waterbodies addressed by the Phase I final rule. 

See 70 FR 71059 (November 25, 2005). Moreover, the importance of controlling impingement 

and entrainment at offshore oil and gas extraction facilities is highlighted by the fact that these 

structures may provide important fish habitat. There are some site specific analyses on the

potential environmental benefits of these “artificial reef” effects; however, EPA was not able to 

locate a comprehensive summary analysis on this topic for the final rulemaking record. Using 

site specific analyses EPA was able to identify that a variety of fish species are known to be 

attracted to and to aggregate around and directly under offshore oil and gas extraction facilities, 

often resulting in densities of fish of that are higher than the densities found in adjacent open 

waters. Both adult fish and young fish gather around these structures. Young fish may be more 

susceptible to impingement and entrainment than adult fish. For example, oil and gas platforms 

and artificial reefs may serve as red snapper habitat. In general, five to 100 times more fish can 

be concentrated near offshore platforms than in the soft mud and clay habitats elsewhere in the 

Gulf of Mexico.20 As a result, 70 percent of all fishing trips in the Gulf of Mexico head for oil 

and natural gas platforms. Likewise, 30 percent of the 15 million fish caught by recreational 

fishermen every year off the coasts of Texas and Louisiana come from the waters around 

platforms. The offshore marine areas in which oil and gas extraction facilities are located contain 

large numbers of fish and shellfish eggs and larvae that drift with ambient currents and have

minimal swimming ability. These organisms are vulnerable to entrainment by oil and gas facility 

cooling water intake structures. Densities of these organisms are variable across offshore marine 

areas, but they can be as great as the densities found in estuarine environments (see preamble 

section IV for further discussion).

EPA will address potential impingement and entrainment impacts at existing facilities through 

NPDES permits on a case-by-case basis, using best professional judgment (see 40 CFR 

125.90(c)). For example, EPA Region 4 has included requirements for existing oil and gas 

extraction facilities to conduct a study to determine technologies or operating procedures to 

reduce the adverse environmental impact of these structures on aquatic life.

EPA applied different regulatory requirements for new oil and gas extraction facilities depending 

on whether they are projecting to use sea chests as their cooling water intake structure. New oil 
and gas extraction facilities without sea chests as cooling water intake structures are required to 

meet impingement and entrainment requirements, while those with sea chests are only required 

to meet impingement requirements. EPA made this distinction based on the potential lack of

technologies to control entrainment impacts at the 316(b) Phase I performance standard for 

cooling water intake structures using sea chests. Simple pipes, caissons and submersible pumps 

used for cooling water extraction can be fitted with premanufactured cylindrical wedgewire 

screens (<1.75 mm slot size) to prevent entrainment and impingement of marine life.

Consequently, control technologies are available for these cooling water intake structures, and 

EPA is promulgating impingement and entrainment control requirements for new offshore oil 

and gas extraction facilities that do not use sea chests.

6. From the Technical Development Document for the Final Section 316(b) Phase III Rule 

(EPA-821-R-06-003), Chapter 8:

II. OFFSHORE OIL AND GAS EXTRACTION FACILITIES AND SEAFOOD PROCESSING 

VESSELS

INTRODUCTION

To identify suitable technologies to minimize impingement mortality and entrainment of fish in 

typical seawater intake structures, the Agency evaluated currently used technologies as well as 

other newly developed technologies. Technologies known to be used at existing seawater intakes 

include standard screens, velocity caps and barrier nets. Other technologies identified as possible 

candidates include acoustic barriers, air curtains and electric barriers. Data on technologies such 

as acoustic or electric barriers were collected and evaluated as they have the potential to limit 

impingement on what are otherwise difficult to modify systems, such as sea chests. Chapter 7 

provides a detailed discussion on the impingement and entrainment control technologies for oil 

and gas extraction facilities that EPA used for estimating incremental compliance costs of the 

final 316(b) Phase III final rule. This chapter also provides information on biofouling control for 

these offshore facilities.

An alternative technology must prove to be practical before progressing as a viable and 

technically feasible candidate technology. The primary criterion for a practical/acceptable 

alternative configuration/technology is that it is successfully implemented at one or more 

facilities, including but not limited to other manufacturing industries with a similar seawater 

intake structure located anywhere around the world.

In addition to identifying appropriate 316(b) control technologies, the following section 

characterizes typical seawater intake structures used by offshore oil and gas extraction facilities 

and/or seafood processing vessels.

1.0 AVAILABLE TECHNOLOGIES

1.1 Known Technologies
There are three main technologies applicable to the control of impingement and entrainment of 

aquatic organisms for cooling water intakes at offshore industry sectors evaluated for this 

rulemaking: passive intake screens, velocity caps, and modification of an intake location. Each 

technology is discussed below with respect to its potential use with intakes at offshore oil and 

gas extraction facilities and seafood processing vessels.

[...]

The use of a passive intake screen on a sea chest for an existing facility (as used by some 

MODUs and many seafood processing vessels) may be limited. This is because the size of the 

opening of a sea chest into the ocean is essentially fixed. To increase the size of a sea chest 

would be very costly due to significant works at a dry dock. A passive screen that has a suitably 

low face velocity may therefore have to protrude outside the hull of the vessel. This would have 

a negative impact on the hydrodynamics of the vessel and create a catch point under the 

waterline. Alternatively, the passive screen may be used in conjunction with another technology

such as an acoustic or electro barrier to reduce impingement, but EPA has no data demonstrating 

the effectiveness of such a combination of technologies for non-fixed facilities. The use of a 

passive intake screen on a sea chest for a new facility may be possible depending on the ship 

design requirements and biofouling controls. Due to the success of passive intake screens at 

many installations around the world, this type of technology is a suitable fish barrier for retrofit 

applications on offshore oil and gas extraction facilities and seafood processing vessels that do 

not employ sea chests.

[...]

[T]here is somewhat limited data on [the performance of velocity caps] when used alone. In the 

case of offshore oil and gas extraction facilities, velocity caps may be used in conjunction with a 

passive intake screen. However, the biofouling drawback of a passive intake screen may also be 

present and existing biofouling control technologies should control these operational concerns. 

Other possible barriers to use in conjunction with a velocity cap may include the “other” 

technologies noted below.

Facilities using sea chests may have limited opportunities to control entrainment as required by

the Phase I rule. EPA recognizes that MODUs using sea chests may require vessel specific 

designs to comply with the final 316(b) Phase III rule. EPA identified that some impingement 

controls for MODUs with sea chests may entail installation of equipment projecting beyond the 

hull of the vessel (e.g., horizontal flow diverters). Such controls may not be practical or feasible 

for some MODUs since the configuration may alter fluid dynamics and impede safe seaworthy

travel, even for new facilities that could avoid the challenges of retrofitting control technologies.

[...]

EPA believes that the cost of modifying existing structures with deeper intakes will be 

significantly greater than the equipment costs associated with screens and velocity caps. In 

addition, the need for an environmental assessment to identify a lower impact zone for modified 

intakes would result in additional cost and time constraints. Therefore, EPA did not include 
modification of an intake location as part of their proposed technology options in the final rule. 

Additionally, this type of technology is not suitable for MODUs since they would operate in 

various locations, depths and environments.

[...]

III. CONCLUSION

As suggested by the technology studies evaluated in this chapter, the technologies presented can 

substantially reduce impingement mortality and entrainment. With proper design, installation, 

and operation and maintenance, a facility can realize marked reductions. However, EPA 

recognizes that there is a high degree of variability in the performance of each technology, which 

is in part due to the site-specific environmental conditions at a given facility. EPA also 

recognizes that much of the data cited in this document was collected under a variety of 

performance standards and study protocols that have arisen over the years since EPA 

promulgated its last guidance in 1977.

EPA expects that this information on technologies may be useful in developing case-by-case, 

best professional judgment permit conditions implementing CWA section 316(b). While EPA 

acknowledges that site-specific factors may affect the efficacy of impingement and entrainment 

reduction technologies, EPA believes that there are a reasonable number of options from which

most facilities may choose. EPA also believes that, in cases where one technology cannot meet 

the performance standards alone, a combination of additional intake technologies, operational 

measures, and/or restoration measures can be employed.