700.0

231 1.0 800.0

231 1.0 900.0

231 1.0 1000.0

231 1.0 1 100.0

231 1.0

30000 35000 40000 45000 50000 55000 60000

1.400

1.500

1.600

1.700

1.800

1.900

2.000

2.100

2.200

2.300

2.400

2.500

2.600

2.700

2.800

2.900

3.000

3.100

3.200

3.300

3.400 872.0

1900.0 872.0

2000.0 872.0

2100.0 872.0

2200.0 872.0

2300.0 872.0

2400.0 872.0

2500.0 872.0

2600.0 872.0

2700.0

15000 20000 25000 30000 35000 40000 45000

1.400

1.500

1.600

1.700

1.800

1.900

2.000

2.100

2.200

2.300

2.400

2.500

2.600

2.700

2.800

2.900

3.000

3.100

3.200

3.300

3.400

Line:

T race:

Horizontal

Distance (ft): EB

689



### Figure EB690-JJ-1. Inline 872 and Crossline 231 1 Showing Conditions Beneath Proposed W ellsite EB690-JJ NOR TH SOUTH

CROSSLINE 231 1 T WO-WAY T RAVEL T IME (SEC) PROPOSED

WELLSITE EB690-JJ T WO-WAY T RAVEL T IME (SEC) WEST EAST Filename: 122051_fig_EB690-JJ-1.cdr

PROPOSED

WELLSITE EB690-JJ Project No. 0212-2051

INLINE 872 Line:

T race:

Horizontal

Distance (ft): EB

690

EB

690 SEAFLOOR

HORIZON 10

HORIZON 20

HORIZON 30

HORIZON 40

100ms

(~250 ft) Scale

5000 ft

100ms

(~250 ft) Scale

5000 ft Peak

T roughRELATIVEAMPLITUDE

EB

646 STUDY AREA

STUDY AREA

SEAFLOOR HORIZON 10

HORIZON 30 HORIZON 40 HORIZON 20

Peak

T roughRELATIVEAMPLITUDE HUMPHRIES

BASIN872.0

2200.0 872.0

2300.0 872.0

2400.0

30000 35000

1.400

1.500

1.600

1.700

1.800

1.900

2.000

2.100

2.200

2.300

2.400

2.500

2.600

2.700

2.800

2.900

3.000

3.100

3.200

3.300

3.400 Li ne :

Tra ce:

Horizontal

Distance (ft):TWO-WAYTRAVELTIME (SEC) W A TER

FLOW AND

GAS

POTENTIAL Shallow W ater Flow and Gas Potential HIGH

0 1 2 3 0 = NEGLIGIBLE

1 = LOW

2 = MODERA

TE

3 = HIGH

HORIZON 30 -3,944 NEGLIGIBLE

Horizon Lithology/Stratigraphy



### Figure EB690-JJ-2. T

ophole Prognosis Chart, Proposed W ellsite EB690-JJ, East Breaks Block 690 Potential Drilling

Constraints Filename: 122051_fig_EB690-JJ-2.cdr Project No. 0212-2051

W ater

Flow Gas 3-D Seismic Section Through

Proposed W ellsite EB690-JJ

X = 1,156,904 FT; Y

= 9,915,286 FT

Inline 872 at Crossline 231 1 

## W E

389 Horizon

TWT

(sec, bml) Depth

(ft, bml) Depth

(ft, bss)

INLINE 872 HORIZON 20 -4,333 0.134

2,649 -6,593 0.841 EB

689 Proposed

W ellsite EB690-JJ

1,577 -5,521 0.519 Horizon

TWT

(sec, bss)

1.617

1.751

2.458 2.136 SEAFLOOR

HORIZON 10

HORIZON 40 724 -4,668 0.246 1.863

2,731 -6,675 0.865 2.482

3,075 -7,019 0.964 2.582 F AUL T

3,646

-7,590 1.125 2.742

5,717 -9,661 1.683 3.300 LIMIT OF

INVESTIGA

TION INTERF ACE INTERF ACE 855

-4,799 0.289 1.906 F AUL T EB

690

There is a negligible potential for high-density benthic

communities within 2,000 ft of the proposed location.

Negligible potential for shallow water flow and shallow gas.

Moderate potential for shallow water flow

. Low potential for shallow gas.

Low potential for shallow water flow and shallow

gas.

Low potential for shallow water flow and shallow gas. Stratified hemipelagic silts and clays with thin, muddy

turbidities.

Predominantly clay-rich mass-transport deposits.

Interbedded mass-transport and channel deposits.

Clay-rich, contains silts and probable thin sand seams.

Clay-rich mass-transport deposits with thin possible

sands and silts. Negligible potential for shallow water flow and shallow gas.

Moderate potential for shallow water flow and shallow

gas.

Low potential for shallow water flow and shallow

gas. Predominantly clay-rich turbidites and gravity flow

deposits, with possible thin sand layers or seams. Interbedded turbidites and mass-transport deposits.

Clay-rich, contains silts and possible thin sand seams.

Potential sand-prone turbidite deposits.

4,733 -8,667 1.422 3.039 INTERF ACE

Peak T rough RELA

TIVE AMPLITUDE F AUL T 5,044

-8,988 1.505 3.122

Moderate potential for shallow water flow and shallow

gas. Potential sand-prone turbidite deposits.

### D

HYDROGEN SULFIDE INFORMATION

Discussions regarding geologic information are considered proprietary and have been omitted

from this public copy of the EP. Anadarko requests that the area be classified as a “zone where the

absence of H 2 

### S has been confirmed.”

### E

BIOLOGICAL, PHYSICAL, AND SO CIOECONOMIC INFORMATION

(a) Chemosynthetic Communities Report

The seafloor disturbing activities proposed in this plan are in approximately 3,881-4,139' of

water. The wells will be drilled with a DP dr illship, DP semi-submersible, or semi-submersible

drilling rig.

Maps

A map prepared using 3-D seismic data to depi ct bathymetry, seafloor and shallow geological

features, and surface locations of the proposed wells is included in Section A.

Analysis

Features or areas that could support high-dens ity chemosynthetic communities are not located

within 2,000' of each proposed muds and cuttings discharge location.

Features or areas that could support high-dens ity chemosynthetic communities are not located

within 250' of any seafloor disturbances.

(b) Topographic Features Map

The proposed activitie s are not within 1,000 ' of a no-activity zone or within the 3-mile radius

zone of an identified topographic feature. Th erefore, no map is requ ired per NTL No. 2008-G04.

(c) Topographic Features Statement (Shunting)

Anadarko does not plan to drill more than two wells from the same surface location within the

Protective Zone of an identifie d topographic feature. Theref ore, the topographic features

statement required by NTL No. 200 8-G04 is not applicable.

(d) Live Bottoms (Pinnacle Trend) Map

The activities proposed in this plan are not within 200' of any pinnacle trend feature with vertical

relief equal to or greater than 8'. Ther efore, no map is required per NTL No. 2008-G04.

(e) Live Bottoms (Low Relief) Map

The activities proposed in this plan are not with in 100' of any live bottom low relief features.

Therefore, no map is required per NTL No. 2008-G04.

### (f) Potentially Sensitive Biological Features

The activities proposed in this pl an are not within 200' of any potentially sensitive biological

features. Therefore, no map is required per NTL No. 2008-G04.

(g) Remotely Operated Vehicle (ROV) Monitoring Survey Plan

East Breaks Blocks 645/689/690 is located within Deepwater Grid Area 4. This grid is

considered to have “inadequate ROV survey co verage”, and, therefore, under the guidance set

out in NTL No. 2008-G06, a Remotely Operated Ve hicle Monitoring Survey Plan is required.

Pursuant to NTL 2008-G06, operators may be re quired to conduct remotely operated vehicle

(ROV) surveys during the propo sed operations for the purpose of biological and physical

observations.

Anadarko is familiar with the ROV survey and reporting provisions of NTL 2008-G06; and if

required, will conduct a survey.

Anadarko will utilize ROV equipped with video imaging capabilities. The survey pattern will

consist of six transects centered on the well lo cation with tracks extending approximately 100

meters away from the well on bearings of 30 degrees, 90 degrees, 150 degrees, 210 degrees, 270

degrees and 330 degrees. The seafloor will be videotaped continuously along each track.

Anadarko will make biological and physical observa tions as described in the subject NTL and

Form BOEM-141 prior to comm encing operations and prior to moving off location. The

observations will be documented using Form BOEM-141, or a facsimile and submitted along

with videotapes, and any other imagery obtain ed, to the BOEM/BSEE within 60 days after

completion of the final ROV survey.

(h) Threatened and Endangered Species Information

Under Section 7 of the Endangered Species Act (ESA) all federal ag encies must ensure that any

actions they authorize, fund, or carry out are not li kely to jeopardize the continued existence of a

listed species, or destroy or adversely modify its designated critical habitat.

In accordance with the 30 CFR 550, Subpart B, effective May 14, 2007, and further outlined in

Notice to Lessees (NTL) 2008-G04, lessees/operators are require d to address site-specific

information on the presence of federally listed threatened or endangere d species and critical

habitat designated under the ESA and marine ma mmals protected under the Marine Mammal

Protection Act (MMPA) in the area of proposes activities under this plan.

Currently there are no designated critical habitats for the listed species in the Gulf of Mexico

Outer Continental Shelf; however, it is possible th at one or more of thes e species could be seen

in the area of our operations. The following table reflects the Federally-listed endangered and

threatened species in the lease ar ea and along the northern Gulf coast:Species Scientific Name Status Potential Presence Critical Habitat

Designated in

Gulf of Mexico Lease

Area Coastal

Marine Mammals

Sperm whale Physeter macrocephalus E X -- None

Florida manatee Trichechus manatus

latirostris E -- X Florida

( Peninsular )

Blue whale B alaeno p tera musculus E X a -- None

Fin whale B alaenoptera physalus E X a -- None

Hum p back whale M e g a p tera novaean g liae E X a -- None

North Atlantic right whale Eubalaena glacialis E X a -- None

Sei whale B alaeno p tera borealis E X a -- None

Sea Turtles

Loggerhead turtle Caretta caretta T X X None

Green turtle Chelonia m y das T, E b X X None

Leatherback turtle Dermochelys coriacea E X X None

Hawksbill turtle Eretmochel y s imbricata E X X None

Kem p ’s ridle y turtle L e p idochel y s kem p ii E X X None

Birds

Piping Plover Charadrius melodus T -- X Coastal Texas,

Louisiana, Mississippi,

Alabama, and Florida

(Panhandle)

Whooping Crane Grus americana E -- X Coastal Texas

(Aransas National

Wildlife Refu g e )

Fishes

Gulf sturgeon Acipenser oxyrinchus desotoi T -- X Coastal Louisiana,

Mississippi, Alabama,

and Florida ( Panhandle )

Terrestrial Mammals

Beach mice (Alabama,

Choctawhatchee, Perdido

Ke y , St. Andrew ) Peromyscus polionotus E -- X Alabama and Florida

(Panhandle) beaches

Abbreviations: E = Endangered; T = Threatened.

a The blue, fin, humpback, North Atlantic right, and sei whales are rare or extralimital in the Gulf of Mexico and are

unlikely to be present in the lease area.

b The green sea turtle is threatened, except for the Florida breeding population, which is listed as endangered.



### The Environmental Impact Analysis in Section N of this plan further discusses potential impacts

and mitigation measures related to threatened and endangered species.

(i) Archaeological Report

East Breaks Blocks 645/689/690 is not in an area designated as an area of high archaeological

potential and, as such, as such, an Archaeologi cal Report is not required per NTL No. 2008-G04.

However an “Archaeological Assessment Repo rt” prepared by C & C Technologies Survey

Services (Project #110397) was previously s ubmitted with the Initial/Supplemental EP,

Plan Control No.: N-9591. The survey in cluded portions of East Breaks Block

601/602/645/646/689/690.

### (j) Air and Water Qu ality Information

This EP does not propose activities for which the State of Florida is an affect ed State. Therefore,

the discussion required per NTL 2008-G04 is not applicable to this EP.

(k) Socioeconomic Information

The activities proposed in this plan are not loca ted offshore Florida. Therefore, socioeconomic

information required per NTL 2008-G04 is not applicable to this EP.

### F

WASTE AND DISCH ARGE INFORMATION

The following estimates were prepared utilizing Anad arko’s experience with si milar drilling operations.

Estimated maximum discharge rates are reflected below.

(a) Projected Generated Wastes

Type of Waste Composition Projected Amount Treatment/Storage/Disposal

Synthetic-based drilling

fluids Synthetic-based

drilling muds 18,000 bbls/well Re-use and/or transport to shore in

tanks and/or cutting boxes to

Fourchon, Louisiana and on to

Newpark Base. If recycled, returned to

vendor (Baroid or MI.)

Cuttings wetted with

synthetic-based muds Cuttings coated with

synthetic drilling

muds/fluids,

including drilled out

cement. 7,000 bbls/well Treated and discharged overboard.

*Note, an estimated 5-10% of cuttings

may be transported to shore in tanks

and/or cutting boxes and on to the

base/transfer station if oil still

remains.

Water-based drilling

fluids Water-based drilling

muds (NaCl

saturated, seawater,

freshwater, barite) 6,000 bbls/well Discharge overboard or at seafloor

Cuttings wetted with

water-based fluids Cuttings coated with

water-based drilling

muds/fluids 2,200 bbls Discharge overboard or at seafloor

Chemical product waste

(well treatment fluids) Ethylene glycol

Methanol 100 bbls/month

25 bbls/month Transport to shore in barrels to

Fourchon, Louisiana for pick up.

Completion Fluids Brine, spent acid,

prop sand, debris 3,000 bbls/ well Transport to shore in barrels to

Fourchon, Louisiana and on to

Newpark Base.

Non-pollutant

completion fluids Low density

uninhibited

completion brines 5,000 bbls/well Discharge overboard

Workover fluids Brine, spent acid,

prop sand, debris 3,000 bbls/well Transport to shore in barrels to

Fourchon, Louisiana and on to

Newpark Base.

Trash Refuse generated

during operations 50 bbls/month Transport to shore in disposal bags by

vessel to shorebase for pickup by

municipal operations.

*Sanitary Wastes Treated human body

waste 300,000 gals/well Chlorinate and discharge overboard

*Domestic Waste Gray water 300,000 gals/well Chlorinate and discharge overboard

Deck drainage Platform washings

and rainwater 210,000 bbls/well Treat for oil and grease and discharge

overboard

Produced water N/A N/A N/A

Desalinization Unit Seawater 21,000 bbls/well Discharge overboard

Wash water Drill water (fresh) 3,000 bbls/60 days

well Discharge overboard

Blowout preventer fluid Blend (3% Stack

Magic & Filtered

Fresh Water) 925 gals/week/well Discharge at seafloor

Ballast water Seawater As needed Discharge overboardCont.

Type of Waste Composition Projected Amount Treatment/Storage/Disposal

Bilge water Seawater 685 bbls/well0 Discharge overboard through 15 ppm

equipment

Excess cement at the

seafloor Nitrified cement

slurry 500 bbls/well Discharge at seafloor

Fire water Seawater 137,142 bbls/day Discharge overboard

Cooling water Seawater 137,142 bbls/day Discharge overboard

Produced Sand N/A N/A N/A

Used oil Excess oil from

engines 3,135 bbls Transport in totes to shore for

recycling

(b) Projected Ocean Discharges

Type of Waste Total Amount to

be Discharged Discharge Rate Discharge Method

*Sanitary Wastes 300,000 gals/well 25 gals per person

daily Chlorinate and discharge overboard

*Domestic waste 300,000 gals/well 25 gals per person

daily Chlorinate and discharge overboard

Deck drainage 210,000 bbls/well 3,500 bbls/day Treat for oil and grease and discharge

Blowout preventer fluid 925 gals/week/well Vents on weekly

basis Discharge at seafloor

Desalinization Unit 21,000 bbls/well 350 bbls/day Discharge overboard

Wash water 3,000 bbls/60 day

well 50 bbls/day Discharge overboard

Ballast water As needed Not continuous Discharge overboard

Bilge water 685 bbls/well 317 bbls/day Discharge overboard through 15 ppm

equipment

Excess cement at the

seafloor 500 bbls/well 20 bbls/min Discharge at seafloor

Fire water 137,142 bbls/day N/A Discharge overboard

Cooling water 137,142 bbls/day N/A Discharge overboard

Cuttings wetted with

water-based fluids 2,200 bbls/well 1,000 bbls/hr max Discharge overboard or at seafloor

Water-based drilling

fluids 6,000 bbls/well 1,000 bbls/hr max Discharge overboard or at seafloor

Cuttings wetted with

synthetic-based fluids 7,000 bbls/well N/A Treated and discharge overboard

Non-pollutant

completion fluids 5,000 bbls/well 100 bbls/hour Discharge overboard

*The rig is designed for maximum personnel capacity of 200 people. The discharge rates are based off of maximum personnel

capacity but will generally not have this many pers onnel onboard during drilling and/or completion operations.



### (c) Modeling Report

The proposed activities under this plan do not meet the U.S. Environmental Protection Agency

requirements for an individual NPDES permit. Therefore, modeling report requirements per

NTL No. 2008-G04 is not applicable to this EP.

### G

AIR EMISSIONS INFORMATION

(a) Screening Questions

Screening Questions for EP’s Yes No

Is any calculated Complex Total (CT) Emission amount (in tons) associated with your

proposed exploration activities more than 90% of the amounts calculated using the

following formulas: CT = 3400D 2/3 for CO, and CT = 33.3D for the other air pollutants

(where D = distance to shore in miles)? No

Do your emission calculations include any emission reduction measures or modified

emission factors? No

Are your proposed exploration activities located east of 87.5 W longitude? No

Do you expect to encounter H 2 S at concentrations greater than 20 parts per million (ppm)? No

Do you propose to flare or vent natural gas for more than 48 continuous hours from any

proposed well? No

Do you propose to burn produced hydrocarbon liquids? No



### (b) Emissions Worksheets

Air emissions worksheets have been prepared using a DP Drillship, DP Semi-submersible, and a

Semi-Submersible drilling rig. Air emissions worksheets are available upon request. Per NTL

No. 2008-G04, if an operator “answers no to all of the above screening questions from the

appropriate table, provide”:

(1) “Summary information regarding the peak year emissions that will be generated by and associated

with your Plan Emissions and Complex Total Emissi ons. This information is compiled on the summary

form of the two sets of worksheets, and you can subm it either these summary forms or the format below.

You do not need to include the entire set of worksheets.”



### (c) Summary Information

East Breaks 645

If drilled with a DP Drillship–EB 645:

Air Pollutant Plan Emission

Amounts 1 (tons)

2014 Calculated

Exemption Amounts 2

(tons) Calculated Complex

Total Emission

Amounts 3 (tons)

Particulate matter (PM) 92.20 3,996.00 92.20

Sulphur dioxide (SO 2 ) 422.99 3,996.00 422.99

Nitrogen oxides (NO

x ) 3,169.53 3,996.00 3,169.53

Volatile organic compounds (VOC) 95.09 3,996.00 95.09

Carbon monoxide (CO) 691.53 82,717.95 691.53

If drilled with a DP Semi-submersible–EB 645:

Air Pollutant Plan Emission

Amounts 1 (tons)

2014 Calculated

Exemption Amounts 2

(tons) Calculated Complex

Total Emission

Amounts 3 (tons)

Particulate matter (PM) 91.32 3,996.00 91.32

Sulphur dioxide (SO 2 ) 418.91 3,996.00 418.91

Nitrogen oxides (NO

x ) 3,139.00 3,996.00 3,139.00

Volatile organic compounds (VOC) 94.17 3,996.00 94.17

Carbon monoxide (CO) 684.87 82,717.95 684.87If drilled with a Semi-submersible–EB 645:

Air Pollutant Plan Emission

Amounts 1 (tons)

2014 Calculated

Exemption Amounts 2

(tons) Calculated Complex

Total Emission

Amounts 3 (tons)

Particulate matter (PM) 39.81 3,996.00 39.81

Sulphur dioxide (SO 2 ) 182.61 3,996.00 182.61

Nitrogen oxides (NO

x ) 1,368.34 3,996.00 1,368.34

Volatile organic compounds (VOC) 41.05 3,996.00 41.05

Carbon monoxide (CO) 298.55 82,717.95 298.55

*Calculated complex total emission amounts (tons) are based on 175 days.

East Breaks 689

If drilled with a DP Drillship–EB 689:

Air Pollutant Plan Emission

Amounts 1 (tons)

2013 Calculated

Exemption Amounts 2

(tons) Calculated Complex

Total Emission

Amounts 3 (tons)

Particulate matter (PM) 92.20 3,996.00 92.20

Sulphur dioxide (SO 2 ) 422.99 3,996.00 422.99

Nitrogen oxides (NO

x ) 3,169.53 3,996.00 3,169.53

Volatile organic compounds (VOC) 95.09 3,996.00 95.09

Carbon monoxide (CO) 691.53 82,717.95 691.53

If drilled with a DP Semi-submersible–EB 689:

Air Pollutant Plan Emission

Amounts 1 (tons)

2013 Calculated

Exemption Amounts 2

(tons) Calculated Complex

Total Emission

Amounts 3 (tons)

Particulate matter (PM) 91.32 3,996.00 91.32

Sulphur dioxide (SO 2 ) 418.91 3,996.00 418.91

Nitrogen oxides (NO

x ) 3,139.00 3,996.00 3,139.00

Volatile organic compounds (VOC) 94.17 3,996.00 94.17

Carbon monoxide (CO) 684.87 82,717.95 684.87

If drilled with a Semi-submersible–EB 689:

Air Pollutant Plan Emission

Amounts 1 (tons)

2013 Calculated

Exemption Amounts 2

(tons) Calculated Complex

Total Emission

Amounts 3 (tons)

Particulate matter (PM) 39.81 3,996.00 39.81

Sulphur dioxide (SO 2 ) 182.61 3,996.00 182.61

Nitrogen oxides (NO

x ) 1,368.34 3,996.00 1,368.34

Volatile organic compounds (VOC) 41.05 3,996.00 41.05

Carbon monoxide (CO) 298.55 82,717.95 298.55

*Calculated complex total emission amounts (tons) are based on 175 days.East Breaks 690

If drilled with a DP Drillship–EB 690:

Air Pollutant Plan Emission

Amounts 1 (tons)

2015 Calculated

Exemption Amounts 2

(tons) Calculated Complex

Total Emission

Amounts 3 (tons)

Particulate matter (PM) 92.20 3,996.00 92.20

Sulphur dioxide (SO 2 ) 422.99 3,996.00 422.99

Nitrogen oxides (NO

x ) 3,169.53 3,996.00 3,169.53

Volatile organic compounds (VOC) 95.09 3,996.00 95.09

Carbon monoxide (CO) 691.53 82,717.95 691.53

If drilled with a DP Semi-submersible–EB 690:

Air Pollutant Plan Emission

Amounts 1 (tons)

2015 Calculated

Exemption Amounts 2

(tons) Calculated Complex

Total Emission

Amounts 3 (tons)

Particulate matter (PM) 91.32 3,996.00 91.32

Sulphur dioxide (SO 2 ) 418.91 3,996.00 418.91

Nitrogen oxides (NO

x ) 3,139.00 3,996.00 3,139.00

Volatile organic compounds (VOC) 94.17 3,996.00 94.17

Carbon monoxide (CO) 684.87 82,717.95 684.87

If drilled with a Semi-submersible–EB 690:

Air Pollutant Plan Emission

Amounts 1 (tons)

2015 Calculated

Exemption Amounts 2

(tons) Calculated Complex

Total Emission

Amounts 3 (tons)

Particulate matter (PM) 39.81 3,996.00 39.81

Sulphur dioxide (SO 2 ) 182.61 3,996.00 182.61

Nitrogen oxides (NO

x ) 1,368.34 3,996.00 1,368.34

Volatile organic compounds (VOC) 41.05 3,996.00 41.05

Carbon monoxide (CO) 298.55 82,717.95 298.55

*Calculated complex total emission amounts (tons) are based on 175 days.

Proposed Activity Start Date End Date No. of Days

Drill and complete Location CC (E B 689) 6/26/2013 12/18/2013 175

Drill and complete Location JJ (E B 690) 12/19/2013 6/12/2014 175

Drill and complete Location GG (EB 645) 6/13/2014 12/5/2014 175

Drill and complete Location GG (EB 689) 12/6/2014 5/30/2015 175

Drill and complete Location FF (E B 690) 5/31/2015 11/4/2015 175



### Air emissions from undrilled well locations under previously appr oved plans: Plan Control No.:

S-7569 and N-9591 are being carried forward in the following table to reflect Anadarko’s current

drilling schedule. No revisions are being requested to the prev iously approved well locations

under this plan:

Proposed Activity Start Date End Date No. of Days

The following “Deep Nansen” proposed well locati ons are mentioned below for reference only:

Drill and complete Location II (EB 645)–Plan Control No . S-7569 previously approved 1/1/2013 6/25/2013 175

Drill and complete Location AA (EB 645)–Plan Control No : N-9591 previously approved 11/5/2015 4/28/2016 175

Drill and complete Location FF (EB 646)–Plan Control No : N-9591 previously approved 4/29/2016 10/21/2016 175

Drill and complete Location EE (EB 645)–Plan Control No : N-9591 previously approved 11/5/2016 4/29/2017 175

Drill and complete Location MM (EB 646)–Plan Control No : N-9591 previously approved 4/30/2017 10/22/2017 175

### The air emission calculations were calculated by:

Bridget O’Farrell

Regulatory Analyst

(832) 636-1694

Bridget.OFarrell-Vi llarreal@anadarko.com

### H

OIL SPILL INFORMATION

(a) Oil Spill Response Planning

(i) OSRP Information

All the proposed activities and facilities in this EP are covered by the Regional Oil Spill

Response Plan (OSRP) approved on August 24, 2012 for Anadarko Petroleum Corporation and

its subsidiaries, Anadarko US Offshore Cor poration and Anadarko E&P Company L.P.

(Company Numbers 00981, 02219 and 00148, respectively) in accordance with 30 CFR Part

254.

(ii) Spill Response Sites

Primary Response Equipment Location(s) Preplanned Staging Location(s)



### Galveston, Texas

Harvey, Louisiana

Houma, Louisiana

Lake Charles, Louisiana

Leeville, Louisiana

Venice, Louisiana Galveston, Texas

Harvey, Louisiana

Fourchon, Louisiana

Cameron, Louisiana

Leeville, Louisiana

Venice, Louisiana

(iii) OSRO Information

Anadarko maintains a contract w ith Clean Gulf Associates (CGA) for spill response equipment.

Various equipment locations are staged throughout the Gulf of Mexico. CGA equipment can be

referenced on their website: http://www.cleangul fassoc.com/. Personnel would be obtained from

the Marine Spill Response Corporation’s (MSRC) STARS network, including a supervisor to

operate the equipment.

In addition Anadarko has a contract with the Marine Spill Response Co rporation (MSRC) for

spill response equipment. MSRC stages equipm ent throughout the Gulf of Mexico and has

recently completed a large expansion of its resources, with particular focus on deepwater. The expansion

is known as “Deep Blue”. 

### MSRC capabilities and a complete equipment listing are available online at: http:// www.msrc.org/.

Anadarko is a member of the Marine Well Containment Company (MWCC), which provides

access to containment response capabilities and incl udes subsea dispersant injection equipment.

### (iv) Worst-Case Scenario Determination

Category Regional OSRP EP EP EP

Type of Activity Exploratory E xploratory Exploratory Exploratory

Facility Location (area/block) GB 346 EB 645 EB 689 EB 690

Facility Designation* Location A* Location EE Location CC Location JJ

Distance to Nearest Shoreline 118 Miles 118 miles 120 miles 120 miles

Storage Tanks (tot al) N/A N/A N/A N/A

Flowlines (on faci lity) N/A N/A N/A N/A

Pipelines N/A N/A N/A N/A

Uncontrolled Blowout 350,000 bopd** 155,400 bopd *** 154,490 bopd 172,789 bopd

Type of Oil(s) Crude Crude Condensate Condensate

API Gravity 30.1 o 27.1 o 49.9o 49.9o

* Note–for the OSRP exploratory worst case discharge scenario only the Area/Block is referenced in the OSRP. Exploratory drilli ng facility

designations (proposed well location names) are typically not included in the OSRP.

** The volume denoted in the Regional OSRP is higher than the NTL No. 2010-N06 (256,700 bopd) and BOEM (321,108 bopd)

calculations approved under EP Plan Control No.: N-9579. Anadarko elected to denote a higher volume in the Regional OSRP for pl anning

purposes to demonstrate equipment response capabiliti es per previous discussions with Rusty Wright.

*** The worst case discharge volume proposed for East Breaks Block 645, Location GG is lower than approved worst case discharge for

the block, Location EE in Plan Control No.: N-9591. Loca tion EE is the approved NTL 2010-N06 volume for the block.



### Anadarko has determined that the worst-case scenario from the activities proposed in this

Supplemental EP does not supersede the worst- case scenario for Garden Banks Block 346 as

previously filed in the Regional OSRP.

Since Anadarko has the cap ability to respond to the worst-case spill s cenario included in our

Regional OSRP, and since the worst-case scenario determined for our EP does not replace the

worst-case scenario in our Regional OSRP approved on August 24, 2012, I hereby certify that

Anadarko has the capability to respond, to the maximum extent practicable, to a worst-case

discharge, or a substantial threat of such a discha rge, resulting from the ac tivities proposed in our

EP.

(b) Worst-Case Discharge Volume Assumptions

Worst-case discharge (WCD) calculations and assump tions within this section utilized guidelines

and requirements pursuant with NTL No. 2010-N 06. The following information summarizes the

WCD scenario for East Breaks Block 690, Location JJ:

(c) Oil Spill Response Discussion

For the purpose of NEPA analys is, the largest spill volume or iginating from the proposed

activity would be an uncontrolled blowout du ring drilling operations at 172,789 barrels of

condensate with an API gravity of 49.9 o 

### . A discussion of the blowout scenario from this proposed

activity is included within this Supplemen tal EP in accordance with NTL No. 2010-N06.

### Land Segment and Resource Identification Modeling

Trajectory of a spill and the probability of its impacting a land segment have been projected

utilizing information in the Oil Spill Risk An alysis Model (OSRAM) for the Central Gulf of

Mexico. Additional information may be referenced in the “Oil-Spill Risk Analysis: Contingency

Planning Statistics for Gulf of Mexico OC S Activities” (OCS Report MMS 2004-026), using the

average conditional probability for 3, 10, and 30 day impacts.

East Breaks Block 690 is located within Launch Area 21. According to the OSRAM, the

trajectory indicates a 9% probability of potential impact to the shoreline in Matagorda County,

Texas. The results are shown in Table H-2.

Matagorda County is identified as the most probable potential imp acted parish or county within

the Gulf of Mexico for this operation. Matagorda County is located in Texas and includes Big

Boggy National Wildlife Refuge (NWR), Aransa s NWR, San Bernard NWR, and Mad Island

Wildlife Management Area (WMA).

### Response

Anadarko will make every effort to respond to the worst-case discharge as effectively as

possible. Response equipment available to respond to the worst-case discharge and the estimated

time of a spill response from oil spill detecti on to equipment deployment on-site is included in

Table H-3. The table estimates individual times needed for procurement, load out, travel time to

the site and deployment. In the event of an actual incident equipment and times can vary.

For the purpose of response scenario discussion , an uncontrolled blowout would be considered

the largest potential spill volume at 172,789 barre ls of condensate. An ADIOS weathering model

was run based on a similar type of oil expected to be produced fr om this well. Based on this

information, approximately 40% (69,116 bbl s) of the initial volume would be

evaporated/dispersed within 24 hours.

If approved and appropriate, 4 sorties (8,000 ga llons) from the Basler ai rcraft and 8 sorties

(9,600 gallons) from two DC-3 aircrafts could disperse approximately 7,540 barrels of oil.

If the conditions are appropriate, and the necessary approvals and permits have been obtained,

in-situ burning may be utilized. Based on in -situ burn operations du ring Deepwater Horizon,

approximately 5% (5,184 bbls) of the wo rst case discharge volume after natural

evaporation/dispersion.

Although unlikely in a spill las ting 30 days, potential shorelin e impact in Matagorda County,

Texas could occur depending on environmental c onditions (wind, currents and temperature) at

the time of an incident. Nearshore response ma y include the use of shoreline boom on beach

areas, or protection/sorbent boom on vegetated ar eas. Surveillance and real time trajectories

would aide in determining the most appropr iate strategies to respond to a spill.

Table H.3 provides an example of offshore and n earshore equipment, response times, and

personnel to respond to a spill of 103,673 barrels, which is the estimated amount that would

remain considering natural evaporation/dispersi on at 24 hours. This amount could be further

reduced through the applicat ion of aerial and subsea dispersants, provided su ch applications were

approved.

Anadarko’s contingency plan for de aling with this worst-case di scharge would be to activate

its Spill Management Team and equipment resour ces as described in it s Gulf of Mexico

Regional Oil Spill Response Plan (OSRP) and provi de continuous support for the duration of the

event. Response resources are activated and supplemented according to need. These resources

would remain engaged in the response until the inci dent is deemed complete or until released by

Unified Command.

Anadarko is a member of the Marine Well Containment Company (MWCC), which provides

access to containment response capabilities and incl udes subsea dispersant injection equipment.

In the event of a blowout, Anadarko may:

### 1. Evacuate personnel, if necessary. Deploy emer gency responders in an effort to preserve

human life, if necessary.

2. Assess the damage and attempt to stop the flow at the source, if safe to do so, to reduce

the amount of oil discharged.

3. Notify agencies.

4. Assess the amount of oil that has been sp illed and calculate add itional potential of oil

flow. A continuous aerial surveillance program w ould be used to assess the growth of the

slick and the volume of oil on the water. Ob servations of the si ze of the slick on the

water, combined with observations at the s ource, would be used to provide a constant

update. Additional potential to release fuel from the remaining tanks onboard the

appropriate DP drillship, DP semi-submersible or semi-submersible drilling rig would be

determined by marine surveyors. Operations and Unified Command would continue to

assess the adequacy of respons e equipment capacities based on this continually updated

mass balance.

5. Convene the Spill Management Team (SMT). Organize Unified Command and establish

objectives and priorities.

6. Monitor the oil spill with aerial surveillance and obtain tr ajectories. If oil is seaward

bound, going away from land, discuss additiona l strategies with Unified Command.

7. If oil is moving in the direction of a shoreline and weather co nditions are favorable,

request approval to u tilize dispersants.

a. Prior to commencing application operati ons, conduct an on-site survey in consultation

with natural resource specialists to determ ine if any threatened or endangered species

are present in the projected application ar ea or otherwise at risk from dispersant

application.

b. Upon approval, mobilize one Basler aircra ft and two DC-3 aircrafts from Houma if

needed, with surveillance aircraft and spo tter. Rotate aircraft, spraying the leading

edge of the spill and working back to the source. Monitor/sample for effectiveness

(USCG SMART Team). Truck additional disp ersants from CGA or MSRC stockpile,

if necessary.

### c. Dispersants are most effective when app lied as soon after discha rge as possible, since

weathering of the oil decreas es dispersant effectiveness. The estimated window of

opportunity for most effectiv e use of dispersants is w ithin 48-72 hours post-release.

The oil may still be dispersible after 72 hours on the water surface, but the

effectiveness of dispersant use would likely be diminished after th e oil has been on the

water for more than three days. Ultimat ely, the USCG SMART monitoring protocol

will be used to determine whether or not dispersant operations are effective.

d. Once the CGA HOSS barge is on locati on and in the skimming mode, dispersants

would only be used if required and approved.

8. Deploy offshore mechanical oil containment and recovery equipment. Attempt to recover

as much oil at sea as possible, utilizing:

a. The CGA HOSS barge, will be positioned in a stationary mode, will be situated downwind and down-current from location fo r long-duration, high-volume skimming.

Based on average travel times, the HO SS barge could be on location within

approximately 51 hours of the release. The de-rated skimming capacity of the HOSS

barge is 43,000 bbls per day. However, only the oil encountered by a skimmer can be

recovered. In order to maximize oil encount er rate, boom will be deployed in a

V-configuration in front of the HOSS barge to funnel oil to the skimmers. If

necessary, temporary barges can be ac tivated to support continuous skimming

operations. (These barges arrive on-site at approximately the same time as the HOSS

barge.) For an on-going release, multiple barges are deployed to provide for

continuous off-loading of skimmer storage vess els and shuttling of recovered oil to an

onshore waste handling facility. Sufficient barges are available to provide enough

temporary storage for continuous recovery operations.

b. CGA’s Fast Response Units (FRU) coul d arrive on-scene between approximately

13.75-28.5 hours of the initial release. Thes e skimmers operate downstream of the

HOSS barge and are used to recover pockets and streamers of oil that may move past

the large stationary skimme r. FRUs have approximat ely 200 barrels of on-board

storage. Approval will be requested to decan t water after gravity separation, through a

hose forward of the skimmer, to optimize temporary storage capacity. Auto boom will

be utilized to concentrate oil so th at it is thick enough to be skimmed.

9. Dispersants, Fast Response Units (FRU), Oil Spill Response Vessels (OSRV or R/V)

would typically work daylight hours onl y. The HOSS barge can operate continuously,

including night operations. Available technology will be considered such as remote

sensing devices that will enable 24 hour surveillance, trajecto ries, and planning. All

response vessels are designed to be able to remain offshore continuously throughout the

response. Even if sea conditions prohibit effective skimming, these resources would

remain offshore until skimming operations c ould be commenced again. Safety would

remain the first priority.

### 10. Prepare site-specific Waste Management Pla n, Site Safety Plan, Decontamination Plans,

Communications and Medical Plans.

11. If oil becomes a threat to any shoreline, da ta from the aerial survei llance, weather reports,

and trajectories would be used to direct onshore teams to deploy protection/containment

boom with reference to Area Contingency Pl ans and in coordination with State and

Federal On-Scene Coordinators.

a. Implement pre-designated strategies.

b. Identify resources at risk in spill vicinity.

c. Develop/implement appropriate protection tactics.

12. Establish site-specific Wildlife Rescue and Rehabilitation Plan.

The following types of additional support may be required for a blowout lasting 120 days.

 Additional Oil Spill Remova l Organization (OSRO) personnel to relieve equipment

operators

 Vessels for supporting offshore operations

 Field safety personnel

 Continued surveillance and m onitoring of oil movement

 Helicopter, video cameras

 Infra red (night time spill track ing) capabilities, X-band radar

 Barge to transport recovered oil from offshore skimming system, and temporary

storage barges to onshore disposal sites th at are identified in Area Contingency Plans

(ACP)

 Logistics needed to support equipment:

- Staging areas

- Parts, trailers, and mechanics to maintain skimmers and boom

- Fueling facilities

- Decontamination stations

- Dispersant stockpile tran sported from Houston to Houma or other potential

command post locations

- Communications equipm ent and technicians

 Logistics needed to s upport responder personnel

- Medical aid stations

- 

### Safety personnel

- Food

- Berthing

- Additional clothing/safety supplies

- Decontamination stations

### Anadarko has the capability to respond and cont ain, to the maximum extent practicable as

defined in 30 CFR 254.6 and 30 CFR 250.26(d)(1), to the estimated wors t case discharge (WCD)

associated with the proposed activity within 30 days. Deployment time for surface containment

equipment is subject to availability and loca tion, weather conditions, potential security zones

around the spill site, and site/well specific assessment data. Personnel safety is always first and

foremost. Refer to further detail s on equipment and timing provided in Section H–Oil Spill

Information and Table H-3 of the EP.

The potential WCD will be further evaluated du ring the Application for Permit to Drill (APD)

process, including the Well Containment Screen ing Tool (WCST) and associated subsea

containment plan for enhanced planning purposes.

There will be no new or unusual technology deployed that has not been previously deployed for

Gulf of Mexico oil spill prev ention, control, and/or cleanup.Table H-1

Worst Case Discharge Calculation

(Based on an Uncontrolled Blowout)

Calculations for an Uncontrolled Blowout: Block 690

i. Type of Oil (crude, condensate, diesel) Condensate

ii. API Gravity 49.9  ̊

iii. EP Location Used for NTL No. 2010-N06 WCD for EB 690 Location JJ

iv. Largest Anticipated WCD Rate during blowout 172,789 bbls

v. WCD Total for Drilling Operations for EB 690 (> 10 miles from shore): 172,789 bblsTable H-2

Trajectory by Land Segment

Following are the average conditional probabilities (expresse d as percent chance) that an oil spill starting at a

particular launch area will contact a la nd segment as included in the Oil Spill Risk Analysis Model (OSRAM) for

the Western Gulf of Mexico. This information can be found on the BSEE website using 3/10/30 day potential

impact, as applicable. The results are listed below.

Area/Block/

Location OCS-G Launch

Area Land Segment and/or Resource Conditional Probability (%)

3

days 10

days 30

days

East Breaks

Block 690,

Location JJ

Drilling

(120 miles from

shore) G22296 Launch

Area 21

Western

Planning

Area Cameron County, TX

Willacy County, TX

Kenedy County, TX

Kleberg County, TX

Nueces County, TX

Aransas County, TX

Calhoun County, TX

Matagorda County, TX

Brazoria County, TX

Galveston County, TX

Jefferson County, TX

Cameron Parish, LA

Vermilion Parish, LA

Iberia Parish, LA

Terrebonne Parish, LA --

--

--

--

--

--

--

--

--

--

--

--

--

--

-- --

--

--

--

--

--

1

1

--

--

--

--

--

--

-- 2

1

4

3

3

4

5

9

3

5

2

5

1

--

--Table H-3WCD Scenario Drilling Activities – Based on an uncontrolled blowout (120 miles from shore)East Breaks Block 690, Location JJ172,789 bbls of condensate (initial volume)103,673 bbls (after evaporation/dispersion)API Gravity 49.9oOffshore Equipment from Spill Detection toEquipment Deployment Response Time:East Breaks Block 690, Location JJOffshore EquipmentOwner/Location Initial StagingHours toStagingAreaTime toProcure(1)TimetoLoad Out(2)TravelTime(Staging/Spill)(3)TimetoDeploy(4)TotalEstimatedResponseTimeTypeDeratedCapacity(bbls)Storage(bbls)No. ofUnits/PersonsBasler Spray AircraftDC 3 Spray AircraftAero Commander--------122ASI/Houma Houma001111.503.5HOSS BargeOperatorsTugs43,000 4,000 183CGA/HarveySTARSVOOHarvey1244046151Texas ResponderTransrec 350 + OSRV4,620'44"Sea Sentry Boom3,300'67"LAMOR10,567 4,000 1114 crewMSRC/Galveston Galveston0222209.25112.25Gulf Coast ResponderTransrec 350 + OSRV5,280'44"Sea Sentry Boom2,640'67"LAMOR10,567 4,000 1114 crewMSRC/Lake Charles Lake Charles02222014.25117.25Deep Blue ResponderLFF 100 Brush + OSRV6,600'44"Sea Sentry Boom660'67"LAMOR18,086 4,000 1114 crewMSRC/Fourchon Fourchon02222019.2122.2FRUOperatorsUtility Boat4,251 200 161CGA/InglesideSTARSVOOIngleside0221212.75116.75FRUOperatorsUtility Boat4,251 200 161CGA/GalvestonSTARSVOOGalveston022129.75113.75FRUOperatorsUtility Boat4,251 200 161CGA/Lake CharlesSTARSVOOCameron.5221215.75119.75FRUOperatorsUtility Boat4,251 200 161CGA/Morgan CitySTARSVOOMorgan City.5221217121FRUOperatorsUtility Boat8,502 400 2122CGA/LeevilleSTARSVOOLeeville0221220124FRUOperatorsUtility Boat8,502 400 2122CGA/VeniceSTARSVOOVenice.5221224.5128.5Spill Team Area Responders (STARS) called out byMarine Spill Response Corporation (MSRC)Vessel of Opportunity=VOOEMS=Enterprise Marine ServicesOffshore Equipment, cont.Owner/Location Initial StagingHours toStagingAreaTime toProcure(1)TimetoLoad Out(2)TravelTime(Staging/Spill)(3)TimetoDeploy(4)TotalEstimatedResponseTimeTypeDeratedCapacity(bbls)Storage(bbls)No. ofUnits/PersonsFRUOperatorsUtility Boat4,251 100 161CGA/HarveySTARSVOOHarvey.5221222126Koseq Skimming Arms,1 setVessel w/ storage/hull17,83010,00021CGA/GalvestonVOOGalveston021129.75123.75MSRC 570 Offshore BargeTugs2 Crucial Disk 88/302,640'44"Sea Sentry II Boom22,244 56,900 1316 crewMSRC/GalvestonVOOGalveston 02222017.25120.25CTCo2603OperatorsTug-- 25,000 161EMS/AmeliaSTARSVOOAmelia0244037142CTCo2604OperatorsTug-- 20,000 161EMS/AmeliaSTARSVOOAmelia0244037142CTCo2605OperatorsTug-- 20,000 161EMS/AmeliaSTARSVOOAmelia0244037142CTCo 5001OperatorsTug-- 45,000 161EMS/AmeliaSTARSVOOAmelia024403714210,000' 42" Auto BoomVOO-- -- 2010 crewCGA/HarveySTARSHarvey.5212221265,000' 42" Auto BoomVOO-- -- 2010 crewCGA/Lake CharlesSTARSCameron.521215.75119.755,000' 42" Auto BoomVOO-- -- 2010 crewCGA/GalvestonSTARSGalveston02129.75113.752,500' 42" Auto BoomVOO-- -- 126 crewCGA/InglesideSTARSIngleside021212.75116.752,500' 42" Auto BoomVOO-- -- 126 crewCGA/PascagoulaSTARSPascagoula021227.75131.7522,400' 42" BoomVOO-- -- 8025 crewAMPOL/New Iberia New Iberia021216.5120.54,800' 42" BoomVOO-- -- 189 crewAMPOL/Harvey Harvey021222126Spotter HeloSurveillance HeloHand Held Radios------------1130PHI/GalvestonPHI/GalvestonSTARSSpill SiteSpill SiteGalveston111.5111.5------1.51.53------2.52.54.5Total 160,553 194,600Nearshore Equipment from SpillDetection to Equipment Deployment Response Time: East Breaks Block 690, Location JJNearshore Equipment*Owner/Location Initial StagingHours toStagingAreaTime toProcure(1)TimetoLoad Out(2)TravelTime(Staging/Spill)(3)TimetoDeploy(4)TotalEstimatedResponseTimeTypeDeratedCapacity(bbls)Storage(bbls)No. ofUnits/PersonsBasler Spray AircraftDC 3 Spray AircraftAero Commander----122ASI/Houma Houma001111.503.5Trinity SWSOperators21,500 249 14CGA/GalvestonSTARSGalveston02129.25113.25SWS EgmopolOperators3,000 100 13CGA/GalvestonSTARSGalveston02124.507.5SWS EgmopolOperators3,000 100 13CGA/Morgan CitySTARSMorgan City.52128011SWS MarcoOperators3,588 34 13CGA/VeniceSTARSVenice.52129.5012.5SWS MarcoOperators3,588 34 13CGA/LeevilleSTARSLeeville.52128.5011.5SWS MarcoOperators3,588 20 13CGA/Lake CharlesSTARSCameron.5212609R/V Grand BayOperators5,000 65 13CGA/VeniceSTARSVenice.522.54.7507.25R/V RW ArmstrongOperators5,000 65 13CGA/LeevilleSTARSLeeville.522.512.75015.25R/V Bastian BayOperators5,000 65 13CGA/Lake CharlesSTARSCameron.522.510.25012.75R/V Timbalier BayOperators5,000 65 13CGA/GalvestonSTARSGalveston022.5608.5CTCo 2606OperatorsTugs-- 20,000 161EMS/Amelia Amelia0244020125CTCo 2607OperatorsTugs-- 23,000 161EMS/Amelia Amelia0244020125CTCo 2608OperatorsTugs-- 23,000 161EMS/Amelia Amelia0244020125CTCo 2609OperatorsTugs-- 23,000 161EMS/Amelia Amelia02440201252,000' Beach Boom -- -- 6 CGA/Galveston Galveston 0 1 2 1.5 2 6.51,000' Beach Boom -- -- 4 CGA/Ingleside Ingleside 0 1 2 3 2 82,000' Beach Boom -- -- 6 CGA/Pascagoula Pascagoula 0 12 4 2 9Nearshore Equipment, cont.Owner/Location Initial StagingHours toStagingAreaTime toProcure(1)TimetoLoad Out(2)TravelTime(Staging/Spill)(3)TimetoDeploy(4)TotalEstimatedResponseTimeTypeDeratedCapacity(bbls)Storage(bbls)No. ofUnits/Persons10,000' 18" BoomVOO-- -- 104 crewOil Mop/New Iberia New Iberia0211731210,000' 18" BoomVOO-- -- 104 crewOil Mop/Houston Houston12112.531310,000' 18" BoomVOO-- -- 104 crewOil Mop/Port Arthur Port Arthur02112.537.510,000' 18" BoomVOO-- -- 104 crewOil Mop/Houma Fourchon.5211631110,000' 18" BoomVOO-- -- 104 crewOil Mop/Port Allen Port Allen02116.25311.2520,000' 18" BoomVOO-- -- 208 crewOil Mop/Belle Chasse Venice.5211761515,000' 18" BoomVOO-- -- 146 crewOil Mop/Gretna Gretna02118414Wildlife Support Trailer -- -- 1/ 2 crew CGA/Harvey Harvey .5 1 2 1.5 3 7.5Bird Scare Cannons -- -- 2 CGA/Venice Venice .5 1 2 2 2 7Bird Scare Cannons -- -- 1CGA/Galveston Galveston 0 1 2 1 2 6Bird Scare Cannons -- -- 1CGA/Ingleside Ingleside 0 1 2 2.5 2 7.5Bird Scare Cannons -- -- 2CGA/Harvey Harvey .5 1 2 1.5 2 6.5Bird Scare Cannons -- -- 2CGA/Lake Charles Cameron .5 1 2 3.5 2 8.5Bird Scare Cannons -- -- 2CGA/Pascagoula Pascagoula 0 1 2 4.5 2 9.5Spotter HeloSurveillance HeloHand Held Radios------------1130PHI/GalvestonPHI/GalvestonSTARSSpill SiteSpill SiteGalveston111.5111.5------1.51.53------2.52.54.5Total 58,264 89,797*Some equipment may be used offshoreup to approximately 25 miles from shoreH-3 (continued)

Operational Limitations of Response Equipment

 HOSS Barge–8 foot seas

 Fast Response Unit (FRU)–8 foot seas

 Oil Spill Response Vessel (OSRV and R/V)–4 foot seas

 Boom–3 foot seas, 20 knot winds

 Dispersants–winds more than 25 knots, visibility less than 3 nautical miles or ceiling less than

1,000 feet

### I

Environmental Monitoring and Envi ronmental Mitigation Measures

(a) Monitoring

If required, Anadarko will monitor loop currents per NTL 2009-G02.

Anadarko subscribes to Wilkins Weather Service which provides real-time weather

conditions such as tropical depressions, st orms and/or hurricanes entering the Gulf.

Additional measures to avoid, minimize, and mitigate environmental impacts is included

in Section N–Environmental Impact Analysis.

(b) Incidental Takes

Although marine mammals may be seen in th e area, Anadarko does not believe that its

operations proposed under this EP will result in the harassment, capture, collection or

killing of any mammals covered by th e Marine Mammal Protection Act.

Anadarko will operate in accordance with appl icable regulations in order to avoid or

minimize incidental takes of marine mammals and other species, including:

 Joint NTL No. 2012-G02 “Implementatio n of Seismic Survey Mitigation

Measures and Protected Species Observer Program”

 BSEE NTL No. 2012-G01 “Marine Tras h and Debris Awareness and

Elimination”, and

 Joint NTL No. 2012-G01 “Vessel Strike A voidance and Injured/Dead Protected

Species Reporting”

### J

LEASE STIPULATIONS INFORMATION

Military Areas

East Breaks Blocks 645/689/690 is located w ithin Military Warning Area W-602.

Anadarko will contact the Fleet Air Reconnaissance Squadron Four (VQ-4) in order to

coordinate and control the electromagnetic emissions dur ing these proposed operations.

VQ-4 Operations Department

7791 Mercury Road

Tinker AFB, Oklahoma 73145-8704

Telephone: (405) 739-5702

Marine Protected Species

This stipulation is meant to reduce the pot ential taking of marine protected species.

Anadarko will operate in accordance with Jo int NTL No. 2012-G01 to minimize the risk

of vessel strikes to protected species and wi ll report observations of injured or dead

protected species. Anadarko will operate in accordance with BSEE NTL No. 2012-G01

to prevent intentional and/or accidental introduction of debris into the marine

environment.

### K

Support Vessels and Aircraft Information

(a) General

Type Max. Total Fuel

Tank Storage

Capacity Max. No. in Area

at any Time Trip Frequency or

Duration

Supply Vessel 336,227 gallons 1 2 trips/week

Helicopter 735.3 gallons 1 10 trips/week

Crew Vessel 50,000 gallons 1 3 trips/week

Tug Boats 218,300 gallons 1-2 Duration of operation

Anchor Handling Vessel 450,698 gallons 1-2 Duration of operation

(b) Diesel Oil Supply Vessels

Fuel for the rig will be transpor ted via a supply vessel as follows:

a. Size of fuel supply vessel: 230 feet

b. Carrying capacity of fu el supply vessel: 336,227 gallons

c. Frequency that fuel supply vessel will visit the

facilities: once per week

d. Routes the fuel supply vessel will use to travel

between the onshore support base and proposed

facility: 6 miles from Port Fourchon to the mouth of

Bayou Lafourche, then approximately 287

miles to EB 690.



### (c) Drilling Fluids Transportation

The following estimates were prepared utilizin g Anadarko’s experience with similar drilling

operations. Estimated quantities are reflected in the table below.



### Type of Material Quantity Being Transported Transportation Method

Water-based drilling fluid

(NaCl saturated, seawater,

freshwater, barite) for Pump

and Dump 13 gallon tote tanks (liquids)

40-63 sacks on pallet (sack

chemicals) Supply boat

Synthetic-based drilling fluid

(internal olefin, ester) 13 gallon tote tanks (liquids)

40-63 sacks on pallet (sack

chemicals) Supply boat

Oil-based drilling fluid N/A N/A

### (d) Solid and Liquid Wastes Transportation

Type of

Waste Composition Total

Projected

Amount Rate Transport

Method Name/Location of

Facility Disposal

Method

Syntheticbased

drilling fluid

or muds Synthetic-based

drilling muds 90,000 bbls 18,000

bbls/well Re-use

and/or

transport to

shore in

tanks. Waste - Port Fourchon,

LA and on to Newpark

Fourchon Transfer Station

#1 & #2. Newpark

Transfer Station Morgan

City. Newpark Transfer

Station Port Arthur. USLL

Galveston and Fourchon

Transfer Station. If

recycled, returned to

vendor (Bariod or MI). Re-used and/or

recycled; if can’t

be reused and/or

recycled the

waste is disposed

of at Newpark

(injection

disposal facility)

or USLL

(landfarm).

Cuttings

wetted with

syntheticbased muds Cuttings coated

with synthetic

drilling muds,

including drilled

out cement 1,750-3,500

bbls 350-700

bbls/well*

*An estimated

5-10% of

cuttings may

be transported

to shore Re-use

and/or

transport to

shore in

tanks and/or

cutting

boxes. Waste - Port Fourchon,

LA and on to Newpark

Fourchon Transfer Station

#1 & #2. Newpark

Transfer Station Morgan

City. Newpark Transfer

Station Port Arthur. USLL

Galveston and Fourchon

Transfer Station. If

recycled, returned to

vendor (Bariod or MI). Re-used and/or

recycled; if can’t

be reused and/or

recycled the

waste is disposed

of at Newpark

(injection

disposal facility)

or USLL

(landfarm).

Chemical

product

waste (well

treatment

fluids) Ethylene glycol

Methanol 2,917 bbls

729 bbls 100

bbls/month

25

bbls/month Transport

to shore in

drums

and/or tote

tanks for

pick up Chemwaste in Sulphur,

LA and Veolia Port

Arthur, TX or to

Newpark, Port Arthur as

non-hazardous waste. Can be returned

to vendor and/or

used at another

facility; MEG is

solidified and

disposed of in a

landfill.

Methanol is

incinerated or

used for fuels

blending.

Completion

fluids Brine, spent

acid, prop

sand, debris 15,000 bbls 3,000

bbls/well Transport

to shore in

cuttings

boxes,

drums,

and/or

vessel tanks

for pick up Sent to Port Fourchon,

LA and on to Newpark

Fourchon Transfer

Station #1 & #2.

Newpark Transfer

Station Morgan City.

Newpark Transfer

Station Port Arthur.

USLL Galveston and

Fourchon Transfer

Station Unused brine

can be returned

to vendor and/or

stored for use

on another job.

Used brine and

spent acid is

transferred to

Newpark's

Processing &

Transfer facility

for injection.

Workover

fluids Brine, spent

acid, prop

sand, debris 15,000 bbls 3,000

bbls/well Transport

to shore in

cuttings

boxes,

drums,

and/or Sent to Port Fourchon,

LA and on to Newpark

Fourchon Transfer

Station #1 & #2.

Newpark Transfer

Station Morgan City. Unused brine

can be returned

to vendor and/or

stored for use

on another job.

Used brine andvessel tanks

for pick up Newpark Transfer

Station Port Arthur.

USLL Galveston and

Fourchon Transfer

Station spent acid is

transferred to

Newpark's

Processing &

Transfer facility

for injection.

Trash and

debris Refuse

generated

during

operations 1,458 bbls 50

bbls/month Transport

to shore in

disposal

bags by

vessel to

shorebase

for pickup

by

municipal

operations Recycled Material in

ARC, New Iberia, LA.

Trash disposed of at

SWDI landfill. Recycled and/or

disposed in

landfill.

Used oil Excess oil from

engines 3,135 bbls 430

bbls/120

days Transport

in totes to

shore for

pick up American Recovery

Fourchon, LA Recycled



### *Total projected amount assumes 5 wells at 175 days/well

(e) Vicinity Map

A vicinity map is included in this section as Attachment K-1.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan

Figure 1. Location of East Break s Blocks 645, 689

, and 690

.

### L

ONSHORE SUPPORT FACILITIES INFORMATION

(a) General

Per NTL No. 2008-G04, the following tables refl ect the onshore faciliti es Anadarko will

utilize to provide supplies and service s upport for the activities proposed in this

Exploration Plan.

Name Primary Location Existing/New/Modified

Anadarko Service Base Fourchon, LA Existing

Name *Alternate Locations Existing/New/Modified

Anadarko Service Base Galveston, TX Existing

Anadarko Service Base Cameron, LA Existing

Anadarko Service Base Lake Charles, LA Existing

Anadarko Service Base Houma, LA Existing

Anadarko Service Base Pascagoula, MS Existing

*In the unlikely event Anadarko’s primary service ba se cannot be utilized Anadarko will exercise the

use of an alternate service base during drilling and/or completion operations.



### (b) Support Base Construction or Expansion

No onshore support base constr uction or expansion is pla nned for these activities.

Therefore dredging or filling activities associated with construction or expansion of

facilities will not be applicable.

(c) Support Base Construction or Expansion Timetable

Since no onshore support base construction or e xpansion is planned for these activities, a

timetable for land acquisition and construc tion or expansion is not applicable.

(d) Waste Disposal

Disposed wastes describe those wastes generated by the proposed activity that are

disposed of by means other than by release into the water of the GOM at the site where

they are generated. These wastes can be di sposed of by offsite release, injection,

encapsulation, or placement at either onshore or offshore permitted locations for the

purposes of returning them back to the environment.Type of

Waste Composition Total

Projected

Amount Rate Transport

Method Name/Location of

Facility Disposal

Method

Syntheticbased

drilling fluid

or muds Synthetic-based

drilling muds 90,000 bbls 18,000

bbls/well Re-use

and/or

transport to

shore in

tanks. Waste - Port Fourchon,

LA and on to Newpark

Fourchon Transfer Station

#1 & #2. Newpark

Transfer Station Morgan

City. Newpark Transfer

Station Port Arthur. USLL

Galveston and Fourchon

Transfer Station. If

recycled, returned to

vendor (Bariod or MI). Re-used and/or

recycled; if can’t

be reused and/or

recycled the

waste is disposed

of at Newpark

(injection

disposal facility)

or USLL

(landfarm).

Cuttings

wetted with

syntheticbased muds Cuttings coated

with synthetic

drilling muds,

including drilled

out cement 1,750-3,500

bbls 350-700

bbls/well*

*An estimated

5-10% of

cuttings may

be transported

to shore Re-use

and/or

transport to

shore in

tanks and/or

cutting

boxes. Waste - Port Fourchon,

LA and on to Newpark

Fourchon Transfer Station

#1 & #2. Newpark

Transfer Station Morgan

City. Newpark Transfer

Station Port Arthur. USLL

Galveston and Fourchon

Transfer Station. If

recycled, returned to

vendor (Bariod or MI). Re-used and/or

recycled; if can’t

be reused and/or

recycled the

waste is disposed

of at Newpark

(injection

disposal facility)

or USLL

(landfarm).

Chemical

product

waste (well

treatment

fluids) Ethylene glycol

Methanol 2,917 bbls

729 bbls 100

bbls/month

25

bbls/month Transport

to shore in

drums

and/or tote

tanks for

pick up Chemwaste in Sulphur,

LA and Veolia Port

Arthur, TX or to

Newpark, Port Arthur as

non-hazardous waste. Can be returned

to vendor and/or

used at another

facility; MEG is

solidified and

disposed of in a

landfill.

Methanol is

incinerated or

used for fuels

blending.

Completion

fluids Brine, spent

acid, prop

sand, debris 15,000 bbls 3,000

bbls/well Transport

to shore in

cuttings

boxes,

drums,

and/or

vessel tanks

for pick up Sent to Port Fourchon,

LA and on to Newpark

Fourchon Transfer

Station #1 & #2.

Newpark Transfer

Station Morgan City.

Newpark Transfer

Station Port Arthur.

USLL Galveston and

Fourchon Transfer

Station Unused brine

can be returned

to vendor and/or

stored for use

on another job.

Used brine and

spent acid is

transferred to

Newpark's

Processing &

Transfer facility

for injection.

Workover

fluids Brine, spent

acid, prop

sand, debris 15,000 bbls 3,000

bbls/well Transport

to shore in

cuttings

boxes,

drums,

and/or

vessel tanks Sent to Port Fourchon,

LA and on to Newpark

Fourchon Transfer

Station #1 & #2.

Newpark Transfer

Station Morgan City.

Newpark Transfer Unused brine

can be returned

to vendor and/or

stored for use

on another job.

Used brine and

spent acid isfor pick up Station Port Arthur.

USLL Galveston and

Fourchon Transfer

Station transferred to

Newpark's

Processing &

Transfer facility

for injection.

Trash and

debris Refuse

generated

during

operations 1,458 bbls 50

bbls/month Transport

to shore in

disposal

bags by

vessel to

shorebase

for pickup

by

municipal

operations Recycled Material in

ARC, New Iberia, LA.

Trash disposed of at

SWDI landfill. Recycled and/or

disposed in

landfill.

Used oil Excess oil from

engines 3,135 bbls 430

bbls/120

days Transport

in totes to

shore for

pick up American Recovery

Fourchon, LA Recycled



### *Total projected amount assumes 5 wells at 175 days/well

### M

COASTAL ZONE MANAGEM ENT ACT INFORMATION

### Texas

The following is an evaluation that includes findings relating the coastal effects of the

proposed activities and associated facilities to the relevant enforceable policies of the

Texas’ Coastal Management Program (TCMP), Title 31, Part 16, Chapter 501,

Subchapter B :

(Category 2)

Construction, Operation & Maintenance of Oil & Gas Exploration & Production

Facilities

No operations are proposed in or near any critical area s. The proposed activities are

explorative in nature, so no facility construction is propose d. The proposed activities are

located approximately 118 miles from the Te xas shoreline; therefore we expect no

adverse impacts to CNRAs or beach access a nd use rights of the public. All activities

shall be conducted in a manner that minimi zes significant impacts to coastal resources.

No adverse effects to Texas’ coastal area are expected in association with the proposed

activities.

(Category 3)

Discharges of Wastewater and Disposal of Waste from Oil and Gas Exploration and

Production Activities

No discharge of wastewater or disposal of waste from the proposed activities will occur

in the Texas’ coastal zone; therefore no imp act to Texas’ coastal waters is expected.

(Category 4)

Construction and Operation of Solid Waste Treatment, Storage, and Disposal

Facilities

No construction of solid waste facilities or expansion of existing facilities in the coastal

zone are proposed in the attached plan, ther efore, no adverse effects on any features of

Texas’ coastal cone are expected.

(Category 5)

Prevention, Response, and Remediation of Oil Spills

The proposed activities will be covered under the Regional O il Spill Response Plan. The

plan is in place, practiced, and updated as ne cessary. The best prac tical techniques shall

be utilized to prevent the release of pollutant s or toxic substances into the environment.

All involved vessels and facilities are design ed to be capable of prompt response and

adequate removal of accidental discharges of oil. In addi tion, the proposed activities are

118 miles from shore; therefore no damages to natural resources are expected as the

result of an unauthorized discha rge of oil into coastal waters.

### (Category 6)

Discharge of Municipal and Industr ial Waste Water to Coastal Waters

No discharges from the proposed activities will occur in coastal waters. The proposed

activities are 118 miles from shore; therefore there will be no effect on coastal waters.

(Category 8)

Development in Critical Areas

None of the proposed activities w ill occur in a criti cal area; therefore no effects to Texas’

coastal zone are expected. The activity will not jeopardize the c ontinued existence of

species listed as endangered or threaten ed, and will not result in likelihood of the

destruction or adverse modifica tion of a habitat determined to be a critical habitat under

the Endangered Species Act. The activity will no t cause or contribute to violation of any

applicable surface water quality standards. Th e activity will not violate any requirement

imposed to protect a marine sanctuary.

(Category 9)

Construction of Waterfront Facilities and Other Structures on Submerged lands

No waterfront facilities or other structures are proposed on submerged lands in the Texas

coastal zone, therefore the pr oposed activities are not exp ected to have any adverse

impacts on submerged lands.

(Category 10)

Dredging and Dredged Material Disposal and Placement

No dredging or disposal/placement of dredge d material is proposed; therefore no adverse

effects to coastal waters, submerged lands, cr itical areas, coastal s hore areas, or Gulf

beaches are expected.

(Category 11)

Construction in the Beach / Dune System

The proposed activities do not include any constr uction projects in cr itical dune areas or

areas adjacent to or on Gulf beaches, ther efore, no impact to Texas’ beach or dune

systems are expected.

(Category 15)

Alteration of Coastal Historic Areas

The proposed activities do not include any altera tion or disturbance of a coastal historic

area; therefore, no impacts are expected to adversely affect any historical, architectural,

or archaeological site in Texas’ coastal zone.

### (Category 16)

Transportation

The proposed activities do not include any tran sportation construction projects within the

coastal zone; therefore, no impacts to Texas’ coastal zone are expected.

(Category 17)

Emission of Air Pollutants

The proposed activities shall be carried out in conformance with a pplicable air quality

laws, standards, and regulations. Emissions fr om the proposed activiti es are not expected

to have significant impacts on onshore air quality because of the prevailing atmospheric

conditions, emission heights, emission rates, an d the distance of these emissions from the

coastline. The proposed activities will occur approximately 118 miles from shore and will

be within the exemption limits set by BOEM, therefore, no impacts to Texas’ coastal

zone is expected.

(Category 18)

Appropriations of Water

The proposed activities do not include the im poundment or diversion of state water,

therefore, no impacts to Texas’ coastal zone is expected.

(Category 20)

Marine Fishery Management

The proposed activities are lo cated approximately 118 miles from shore and are not

expected to have any effect on marine fish ery management or fishery migratory patterns

within waters in the coastal zone of Texas.

(Category 22)

Administrative Policies

The necessary information for applicable agencies to make an informed decision on the

proposed activities has been provided In conclu sion, all activities shall be consistent with

Texas’ coastal management program and shall comply with all relevant rules and

regulations. No activities are planned within any critical areas. Activities will be carried

out avoiding unnecessary conflicts w ith other uses of the vicinity.

### LOUISIANA

Issues identified in the Louisiana Coas tal Zone Management Program include the

following: general coastal use guidelines, levees , linear facilities (pipelines); dredged soil

deposition; shoreline modifications, surf ace alterations, hydrologic and sediment

transport modifications, waste disposal; uses that result in the alteration of waters

draining into coastal waters; oil, gas, or other mineral activitie s; and air and water quality.

Relevant enforceable policies were considered in certifying consistency for Louisiana.

### MISSISSIPPI

As authorized by the Federal Coastal Zone Management Act (CZMA), The State of

Mississippi developed a Coastal Management Pr ogram (CMP) to allow for the review of

proposed Federal license and perm it activities affecting any coasta l use or resources, in or

outside of the Missi ssippi Coastal Zone.

The OCS related oil and gas exploratory and development activities having potential

impact on the Mississippi Coastal Zone are based on the location of the proposed

facilities, access to those sites, best prac tical techniques for drilling locations, drilling

equipment guidelines for the prevention of adverse environmental effects, effective

environmental protection, emergenc y plans and contingency plans.

Below are goals identified by the State of Mississippi and our comments and/or

corresponding cross references:

Goal 1: To provide for reasonable industrial expansion in the coastal area and to

ensure the efficient utilization of waterfront industrial sites so that suitable sites are

conserved for water dependent industry.

The activities proposed in this plan are based out of Fourcho n, Louisiana. The activities

will not provide any industrial expansion on the coastal area of Mississippi. Therefore

Mississippi coastal areas will be cons erved for water dependent industry.

Goal 2: To favor the pres ervation of the coastal wetlands and ecosystems, except

where a specific alteration of specific coas tal wetlands would serve a higher public

interest in compliance with the public pur poses of the public trust in which the

coastal wetlands are held.

Goal 2 is addressed in Section N–Environm ental Impact Analysis. The nearest proposed

activities will be 450 miles fr om the Mississippi coast.

Goal 3: To protect, propagate and conserve the state’s seafood and aquatic life in

connection with the revitalization of the se afood industry of the State of Mississippi.

Goal 3 is addressed in Sec tion N–Environmental Impact An alysis. Little impact to the

seafood industry can be expected due to th e activities occurring 450 miles from the

Mississippi coast.

Goal 4: To conserve the air and waters of the state, and to protect, maintain and

improve the quality thereof for public use, for the propagation of wildlife, fish and

aquatic life, and for domestic, agricultu ral, industrial, recreational and other

legitimate beneficial uses.

Goal 4 is addressed in Section B–Gene ral Information, Section G–Air Emissions

Information, and Section N–Environmental Impact Analysis.

### Goal 5: To put to beneficial use to the fu llest extent of which they are capable the

water resources of the state, and to prevent the waste, unreasonable use, or

unreasonable method of use of water.

The activities proposed in this plan are based in Fourchon, Louisiana. As such,

Mississippi’s water resources should not be impacted by the proposed activities.

Activities occurring at the sites in the OC S will be conducted in accordance with our

Regional Oil Spill Response Plan refere nced in Section H of this plan.

Goal 6: To preserve the state’s historical and archaeological resources, to prevent

their destruction, and to enhance these resources wherever possible.

Goal 6 is addressed in Section B–Genera l Information, and Section N–Environmental

Impact Analysis.

Goal 7: To encourage the preservation of na tural scenic qualities in the coastal area.

Goal 7 is addressed in Section F–Wastes and Discharge Information, Section H–Oil Spill

Information, Section G–Air Emissions In formation, and Section N–Environmental

Impact Analysis.

Goal 8: To assist local govern ments in the provision of public facilities services in a

manner consistent with the coastal program.

As the proposed activities ar e located 450 miles from the Mi ssissippi coast and are based

out of a shorebase in Fourchon, Louisiana, local governments should not be affected.

### N

ENVIRONMENTAL IMPACT ANALYSIS

# Environmental Impact Analysis

SUPPLEMENTAL EXPLORATION PLAN

for

East Breaks Block 645 (OCS

‐ G 32822)

East Breaks Block 689 (OCS

‐ G 22295)

East Breaks Block 690 (OCS

‐ G 22296)

Offshore Texas

May 2012

Prepared for:

Bridget O'Farrell

Regulatory Analyst

Anadarko Petroleum Corporation

1201 Lake Robbins Drive

The Woodlands, Texas 77380

Telephone: (832) 636

‐ 1694

Prepared by:

CSA International, Inc.

8502 SW Kansas Avenue

Stuart, Florida 34997

Telephone: (772) 219

‐ 3000East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page ii 

## Contents

Page



### Introduction

................................................................................................................ 1

A. Impact

‐ Producing Factors

....................................................................................... 5

A.1 Drilling Rig Presence (including noise and lights)

........................................................................... 5

A.2 Physical Disturbance to the Seafloor

.............................................................................................. 8

A.3 Air Pollutant Emissions

................................................................................................................... 8

A.4 Effluent Discharges

......................................................................................................................... 8

A.5 Water Intake

............................................................................................................................... .... 9

A.6 Onshore Waste Disposal

................................................................................................................. 9

A.7 Marine Debris

............................................................................................................................... .. 9

A.8 Support Vessel and Helicopter Traffic

............................................................................................ 9

A.9 Accidents

............................................................................................................................... ....... 10

A.9.1 Types of Accidents Evaluated

........................................................................................... 10

A.9.2 Small Fuel Spill

.................................................................................................................. 10

A.9.3 Crude Oil Spill (Worst Case Discharge)

............................................................................. 11

A.9.4 Other Accidents Not Analyzed in Detail

............................................................................ 15



### B. Affected Environment

........................................................................................... 17

C. Impact Analysis

..................................................................................................... 19

C.1 Physical/Chemical Environment

................................................................................................... 19

C.1.1 Air Quality

......................................................................................................................... 19

C.1.2 Water Quality

.................................................................................................................... 21

C.2 Seafloor Habitats and Biota

.......................................................................................................... 23

C.2.1 Soft Bottom Benthic Communities

................................................................................... 24

C.2.2 High

‐ Density Deepwater Benthic Communities

............................................................... 26

C.2.3 Designated Topographic Features

.................................................................................... 28

C.2.4 Pinnacle Trend Area Live Bottoms

.................................................................................... 29

C.2.5 Live Bottom/Low Relief

..................................................................................................... 29

C.3 Threatened, Endangered, and Protected Species and Critical Habitat

........................................ 29

C.3.1 Sperm Whale (Endangered)

.............................................................................................. 31

C.3.2 West Indian Manatee (Endangered)

................................................................................. 35

C.3.3 Endangered Mysticete Whales

......................................................................................... 36

C.3.4 Non

‐ Endangered Marine Mammals (Protected)

.............................................................. 36

C.3.5 Sea Turtles (Endangered/Threatened)

............................................................................. 39

C.3.6 Piping Plover (Threatened)

............................................................................................... 42

C.3.7 Whooping Crane (Endangered)

........................................................................................ 44

C.3.8 Gulf Sturgeon (Threatened)

.............................................................................................. 44

C.3.9 Smalltooth Sawfish (Endangered)

..................................................................................... 45

C.3.10 Beach Mice (Endangered)

................................................................................................. 46

C.3.11 Elkhorn Coral (Threatened)............................................................................................... 47

## Contents

(Continued)

Page

East Breaks Blocks 645, 689, and 690 April 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page iii C.4 Coastal and Marine Birds

.............................................................................................................. 47

C.4.1 Marine Birds

...................................................................................................................... 47

C.4.2 Shorebirds and Coastal Nesting Birds

............................................................................... 50

C.5 Fisheries Resources

...................................................................................................................... 52

C.5.1 Pelagic Communities and Ichthyoplankton

...................................................................... 52

C.5.2 Essential Fish Habitat

........................................................................................................ 54

C.6 Archaeological Resources

............................................................................................................. 57

C.6.1 Shipwreck Sites

................................................................................................................. 57

C.6.2 Prehistoric Archaeological Sites

........................................................................................ 59

C.7 Coastal Habitats and Protected Areas

.......................................................................................... 59

C.8 Socioeconomic and Other Resources

........................................................................................... 63

C.8.1 Recreational and Commercial Fishing

.............................................................................. 63

C.8.2 Public Health and Safety

................................................................................................... 64

C.8.3 Employment and Infrastructure

....................................................................................... 65

C.8.4 Recreation and Tourism

.................................................................................................... 66

C.8.5 Land Use

............................................................................................................................ 67

C.8.6 Other Marine Uses

............................................................................................................ 67



### D. Environmental Hazards

......................................................................................... 68

D.1 Geologic Hazards

.......................................................................................................................... 68

D.2 Severe Weather

............................................................................................................................ 68

D.3 Currents and Waves

..................................................................................................................... 68



### E. Alternatives

.......................................................................................................... 69

F. Mitigation Measures

............................................................................................. 69

G. Consultation

......................................................................................................... 69

H. Preparers

.............................................................................................................. 69

I. References

............................................................................................................. 69East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page iv 

## List of Tables

Table Page

1 Notices to Lessees and Operators (NTLs) applicable to this Environmental Impact

Analysis (EIA)

......................................................................................................................... 3

2 Matrix of impact

‐ producing factors and affected environmental resources

........................ 6

3 Conditional probabilities expressed as percent chance that an oil spill starting at

Launch Point 5 will contact a certain parish, county, or coastline within 120 days

(Modified from: BOEM, 2012)

............................................................................................. 13

4 Benthic community data from stations near the lease area (Adapted from:

Wei, 2006; Rowe and Kennicutt, 2009)

............................................................................... 24

5 Federally listed endangered and threatened species potentially occurring in the

lease area and along the northern Gulf Coast

.................................................................... 30

6 Wildlife refuges, wilderness areas, and State and National parks within the

geographic range of the potential shoreline contacts after 120 days (From: BOEM,

2012)

............................................................................................................................... ..... 61



## List of Figures

Figure Page

1 Location of East Breaks 645, 689 and 690

............................................................................. 2

2 Bathymetric map (in meters) of the lease area showing proposed well surface

locations

.............................................................................................................................. 18

3 Location of selected environmental features in relation to the lease area

........................ 43East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page v 

## Acronyms and Abbreviations

ADIOS2 Automated Data Inquiry for Oil Spills 2

Anadarko Anadarko Petroleum Corporation

bbl barrel

BHL bottom hole location

BLPD barrels of liquid per day

BOEM Bureau of Ocean Energy Management

BOEMRE Bureau of Ocean Energy Management,

Regulation and Enforcement

BOP blowout preventer

BOPD barrels of oil per day

B.P. Before Present

BSEE Bureau of Safety and Environmental

Enforcement

CH 4 methane

CO carbon monoxide

CO 2 carbon dioxide

CEI Coastal Environments, Inc.

CFR Code of Federal Regulations

CGA Clean Gulf Associates

DD Destin Dome

DP dynamically positioned

EA Environmental Assessment

EB East Breaks

EEZ Exclusive Economic Zone

EFH Essential Fish Habitat

EIA Environmental Impact Analysis

EIS Environmental Impact Statement

ESA Endangered Species Act

FAD fish

‐ attracting device

FR Federal Register

FRV fast response vessel

GEMS Geoscience Earth and Marine Services,

Inc.

GPS global positioning system

GMFMC Gulf of Mexico Fishery Management

Council

H 2 S hydrogen sulfide

HAPC Habitat Area of Particular Concern

HOSS high

‐ volume open sea skimmer

IPF impact

‐ producing factor MARPOL International Convention for the

Prevention of Pollution from Ships

MMC Marine Mammal Commission

MMPA Marine Mammal Protection Act

MMS Minerals Management Service

MMSCFD million standard cubic feet per day

MP Main Pass

MSRC Marine Spill Response Corporation

MWCC Marine Well Containment Company

NAAQS National Ambient Air Quality Standards

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric

Administration

NO 2 nitrogen dioxide

NO

x nitrogen oxides

NPDES National Pollutant Discharge Elimination

System

NPS National Park Service

NRDA Natural Resource Damage Assessment

NTL Notice to Lessees and Operators

NWR National Wildlife Refuge

OCS Outer Continental Shelf

OSAT Operational Science Advisory Team

OSRA Oil Spill Risk Analysis

OSRB oil spill response barge

OSRP Oil Spill Response Plan

OSRV oil spill response vessel

PAH polycyclic aromatic hydrocarbon

PM particulate matter

PSD Prevention of Significant Deterioration

PSV platform supply vessel

SBM synthetic

‐ based mud

SEP Supplemental Exploration Plan

SHL surface hole location

SO

x sulfur oxides

SWSS Sperm Whale Seismic Study

USCG U.S. Coast Guard

USEPA U.S. Environmental Protection Agency

USFWS U.S. Fish and Wildlife Service

VOC volatile organic compound

WCD worst case dischargeEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 1 

## Introduction

Anadarko Petroleum Corporation (Anadarko) is submitting a Supplemental Exploration Plan

(SEP) for East Breaks (EB) Blocks 645, 689, and 690. The SEP includes five wells: one in EB 645

designated GG; two in EB 689 designated CC and GG; and two in EB 690 designated FF and JJ.

Surface hole locations (SHLs) of all wells will be in their respective Blocks. This Environmental

Impact Assessment (EIA) provides an analysis of all five exploratory wells based on their SHLs.

The lease area is 120 miles (194 km) south

‐ southeast of the nearest shoreline (Texas), 287 miles

(463 km) from the onshore support base at Fourchon, Louisiana, and 277 miles (446 km) from

the helicopter support base at Houma, Louisiana ( Figure 1 ). Water depths at the proposed well

sites range from 1,156 to 1,262 m (3,794 to 4,139 ft). The drilling rig is yet to be determined but

will be either a dynamically positioned (DP) drillship, a DP semisubmersible, or an anchored

semisubmersible.

This EIA was prepared for submittal to the Bureau of Ocean Energy Management (BOEM 1 ) in

accordance with applicable regulations, and is a project

‐ and site

‐ specific analysis of Anadarko’s

planned activities. As specified in the Notice to Lessees and Operators (NTL) 2008

‐ G04, an EIA is

a project

‐ specific analysis that focuses on the impacts of a specific plan to the extent feasible.

Potential impacts have been analyzed at a broader level in the Programmatic Environmental

Impact Statement (EIS) for the Outer Continental Shelf (OCS) Oil and Gas Leasing Program

(MMS, 2007a) and in lease sale EISs for the Western and Central Gulf of Mexico Planning Areas

(MMS, 2007b, 2008). The analyses from these documents are incorporated here by reference.

Updated environmental baseline information relative to the Macondo incident presented in the

Final Supplemental EIS for Central Planning Lease Sale 216/222 (BOEM, 2012) and the Final

Supplemental EIS for Western Planning Area Lease Sale 218 (BOEMRE, 2011a) has also been

incorporated.

Statistics from offshore drilling in the U.S. Gulf of Mexico provide a reasonable basis for

evaluating oil spill risk during exploratory drilling. According to Holand (1997), the average

frequency of a loss of well control incident or “blowout” during exploratory drilling in the

U.S. Gulf of Mexico is 0.00593 blowouts per well drilled, or one blowout per 169 exploration

wells drilled. Similarly, the MMS Safety and Environmental Management Program blowout

incident rate for 1996 to 1999 was approximately five blowouts per 1,000 well starts, or one

blowout per 200 well starts (MMS, 2000). More recently, in its Final Supplemental EIS for the

Central Gulf of Mexico Planning Area, BOEM confirmed that “significant changes to the spill

rates for the entire OCS are not anticipated” (BOEM, 2012).

Historically, most blowouts have not resulted in oil spills. Of 151 well blowouts in the Gulf of

Mexico from 1971 to 1995, only 18 (12%) resulted in oil spills, with a total combined volume of

1,000 barrels (bbl) of crude oil and condensate released (MMS, 2000). Between 1964 and 1999,

almost all offshore spills (94%) from drilling and production

‐ related operations on the OCS were

less than or equal to 1 bbl in size (Anderson and LaBelle, 2000). According to BOEMRE’s Interim

Final Drilling Safety Rule (75 Federal Register (FR) 63365 dated 10 October 2010) issued

following the Macondo incident, the baseline risk of a catastrophic blowout is estimated to be

about once every 26 years.

1 On 1 October 2011, the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE), formerly the

Minerals Management Service (MMS), was replaced by the BOEM and the Bureau of Safety and Environmental Enforcement

(BSEE) as part of a major reorganization.EastBreaksBlocks645,689,and690May2012EnvironmentalImpactAnalysisforSupplementalExplorationPlanPage2Figure1.LocationofEastBreaksBlocks645,689,and690.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 3 Anadarko submitted an updated Gulf of Mexico Regional Oil Spill Response Plan (OSRP) and a

Regional OSRP Certification Letter per 30 Code of Federal Regulations (CFR) 254.2(b) to BOEMRE

on 21 July 2011. The Certification Letter was accepted by BOEMRE on 27 July 2011. Additional

updates have been submitted to BSEE for review. The OSRP details Anadarko’s plan for

response to rapidly and effectively manage oil spills that may result from drilling and production

operations. Anadarko has designed its response program based on a regional capability of

response to spills ranging from small operational spills to a worst case discharge (WCD) from a

well blowout. Anadarko’s spill response program meets the response planning requirements of

the relevant coastal states and applicable Federal oil spill planning regulations and also includes

information regarding Anadarko’s regional oil spill organization and dedicated response assets,

potential spill risks, and local environmental sensitivities. The OSRP describes personnel and

equipment mobilization, the incident management team organization, and an overview of

actions and notifications to be taken in the event of a spill.

This EIA is organized into Sections A through I corresponding to the information required by

NTL 2008

‐ G04. The main impact

‐ related discussions are in Section A (Impact

‐ Producing Factors)

and Section C (Impact Analysis). Table 1 lists and summarizes the BOEM, BSEE, and JOINT NTLs

applicable to this EIA.

Table 1. Notices to Lessees and Operators (NTLs) applicable to this Environmental Impact

Analysis (EIA).

NTL Title Summary

2012

‐ BSEE

‐ G01 Marine Trash and Debris

Awareness and Elimination Instructs operators to exercise caution in the handling and

disposal of small items and packaging materials; requires the

posting of placards at prominent locations on offshore

vessels and structures; and mandates a yearly marine trash

and debris awareness training and certification process.

2012

‐ JOINT

‐ G01 Vessel Strike Avoidance and

Injured/Dead Protected Species

Reporting Recommends protected species identification training,

recommends that vessel operators and crews maintain a

vigilant watch for marine mammals and slow down or stop

their vessel to avoid striking protected species, and requires

operators to report sightings of any injured or dead

protected species.

2011

‐ JOINT

‐ G01 Revisions to the List of OCS Blocks

Requiring Archeological Resources

Surveys and Reports Provides new information of which OCS blocks require

archeological surveys and reports and required line spacing

in each block. This NTL augments NTL 2005

‐ G07.

2010

‐ N10 Statement of Compliance with

Applicable Regulations and

Evaluation of Information

Demonstrating Adequate Spill

Response and Well Containment

Resources Informs operators using subsea blowout preventers (BOPs)

or surface BOPs on floating facilities that applications for

well permits must include a statement signed by an

authorized company official stating that the operator will

conduct all activities in compliance with all applicable

regulations, including the increased safety measures

regulations (75 FR 63346). Informs operators that BOEMRE

will be evaluating whether each operator has submitted

adequate information demonstrating that it has access to

and can deploy containment resources to promptly respond

to a blowout or other loss of well control.

2010

‐ N06 Information Requirements for

Exploration Plans, Development

and Production Plans, and

Development Operations

Coordination Documents on the

OCS Rescinds the limitations set forth in NTL 2008

‐ G04 regarding

a blowout scenario and worst case discharge scenario, and

provides guidance regarding the information required in

blowout scenario and worst case discharge scenario

descriptions.Table 1. (Continued).

East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 4 NTL Title Summary

2009

‐ G40 Deepwater Benthic Communities Guidance for avoiding and protecting high

‐ density

deepwater benthic communities (including chemosynthetic

and deepwater coral communities) from damage caused by

Outer Continental Shelf (OCS) oil and gas activities in water

depths greater than 300 m (984 ft). Prescribes separation

distances of 610 m (2,000 ft) from each mud and cuttings

discharge location and 76 m (250 ft) from all other seafloor

disturbances.

2009

‐ G39 Biologically Sensitive Underwater

Features and Areas Guidance for avoiding and protecting biologically sensitive

features and areas (i.e., topographic features, pinnacles, low

relief live bottom areas, and other potentially sensitive

biological features) when conducting OCS operations in

water depths less than 300 m (984 ft) in the Gulf of Mexico.

2009

‐ G06 Military Warning and Water Test

Areas Provides contact links to individual command headquarters

for the military warning and water test areas in the Gulf of

Mexico. Lease stipulations require lessees or designated

operators to enter into an agreement with the appropriate

individual military command headquarters concerning the

control of electromagnetic emissions and use of boats and

aircraft in the applicable warning area or water test area

before commencing such traffic.

2008

‐ G04 Information Requirements for

Exploration Plans and

Development Operations

Coordination Documents Guidance on the information requirements for OCS plans,

including EIA requirements and information regarding

compliance with the provisions of the Endangered Species

Act and Marine Mammal Protection Act.

2005

‐ G07 Archaeological Resource Surveys

and Reports Provides guidance on regulations regarding archaeological

discoveries, specifies requirements for archaeological

resource surveys and reports, and outlines options for

protecting archaeological resources.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 5 

## A. Impact

‐ Producing Factors

Table 2 is a matrix of impact

‐ producing factors (IPFs) and potentially affected environmental

resources adapted from Form MMS

‐ 142. An “X” indicates that an IPF could reasonably be

expected to affect a certain resource, and a dash (

‐‐ ) indicates no impact or negligible impact.

Where there may be an effect, an analysis is provided in Section C

. Potential IPFs for the

proposed activity are listed below and briefly discussed in the following sections.

 Drilling rig presence (including noise

and lights)

 Physical disturbance to the seafloor

 Air pollutant emissions

 Effluent discharges  Water intake

 Onshore waste disposal

 Marine debris

 Support vessel and helicopter traffic

 Accidents



## A.1 Drilling Rig Presence (including noise and lights)

Three types of exploratory drilling rigs are available for this project:

 DP drillship;

 DP semisubmersible; and

 moored semisubmersible.

DP drillships and DP semisubmersibles use a global positioning system (GPS), specific computer

software, and sensors in conjunction with and their own propellers and thrusters to maintain

position. Through satellite navigation, the location of the vessel is precisely monitored, and

thrusters positioned at various locations about the vessel’s hull are activated to provide

required station

‐ keeping adjustment. This allows operations at sea where mooring or anchoring

is not feasible.

An anchored semisubmersible requires the placement of anchors on the seafloor and is

therefore subject to NTL 2009

‐ G40, which requires that anchors be placed a minimum of 76 m

(250 ft) from deepwater benthic communities.

The drilling vessel for the wells proposed in this SEP will be on site for an estimated 875 days

(175 days to drill and complete each well). The physical presence of the drilling rig in the ocean

can attract pelagic fishes and other marine life, as discussed in Section C.5.1

.

Drilling operations produce noise that includes strong tonal components at low frequencies and,

in some cases, infrasonic frequencies (MMS, 2000). Drilling noise from drillships and

semisubmersibles is not particularly intense and is strongest at low frequencies, averaging

10 to 500 Hz (Richardson et al., 1995). From a drilling rig, sound and vibration paths to the

water flow either through the air or through the risers (MMS, 2000). Drilling rigs also maintain

exterior lighting for navigational and aviation safety in accordance with applicable Federal safety

regulations.EastBreaksBlocks645,689,and690May2012EnvironmentalImpactAnalysisforSupplementalExplorationPlanPage6Table2.Matrixofimpact‐producingfactorsandaffectedenvironmentalresources.X=potentialimpact;dash(‐‐)=noimpactornegligibleimpact.EnvironmentalResourcesImpact‐producingFactorsDrillingRigPresence(incl.noise&lights)PhysicalDisturbancetoSeafloorAirPollutantEmissionsEffluentDischargesWaterIntakeOnshoreWasteDisposalMarineDebrisSupportVessel/HeloTrafficAccidentsSmallFuelSpillOilSpill(WCD)Physical/ChemicalEnvironmentAirqualityandgreenhousegases‐‐ ‐‐X(9)‐‐ ‐‐  ‐‐ ‐‐ ‐‐X(6)X(6)Waterquality‐‐ ‐‐ ‐‐X‐‐  ‐‐ ‐‐ ‐‐X(6)X(6)SeafloorHabitatsandBiotaSoftbottombenthiccommunities‐‐X‐‐X‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)High‐densitydeepwaterbenthiccommunities‐‐ ‐‐(4)‐‐X(4)‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)Designatedtopographicfeatures‐‐ ‐‐(1)‐‐ ‐‐(1)‐‐  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐Pinnacletrendarealivebottoms‐‐ ‐‐(2)‐‐ ‐‐(2)‐‐  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐LiveBottom/Low‐Relief‐‐ ‐‐(3)‐‐ ‐‐(3)‐‐  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐Threatened,Endangered,andProtectedSpeciesandCriticalHabitatSpermwhale(endangered)X(8)‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐X(8)X(6,8)X(6,8)WestIndianmanatee(endangered)‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐X(8)‐‐X(6,8)Endangeredmysticetewhales‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐ ‐‐Non‐endangeredmarinemammals(protected)X‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐XX(6)X(6)Seaturtles(endangered/threatened)X(8)‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐X(8)X(6,8)X(6,8)PipingPlover(threatened)‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)WhoopingCrane(endangered)‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)Gulfsturgeon(threatened)‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)Smalltoothsawfish(endangered)‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)Beachmice(endangered)‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)Elkhorncoral(threatened)‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)CoastalandMarineBirdsMarinebirdsX‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐XX(6)X(6)Shorebirdsandcoastalnestingbirds‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐X‐‐X(6)FisheriesResourcesPelagiccommunitiesandichthyoplanktonX‐‐ ‐‐XX‐‐ ‐‐ ‐‐X(6)X(6)EssentialfishhabitatX‐‐ ‐‐XX‐‐ ‐‐ ‐‐X(6)X(6)ArchaeologicalResourcesShipwrecksites‐‐ ‐‐(7)‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)Prehistoricarchaeologicalsites‐‐ ‐‐(7)‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)CoastalHabitatsandProtectedAreasBeaches‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐X‐‐X(6)Wetlandsandseagrassbeds‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐X‐‐X(6)Coastalwildliferefugesandwildernessareas‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐X‐‐X(6)SocioeconomicandOtherResourcesRecreationalandcommercialfishingX‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐X(6)X(6)Publichealthandsafety‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)Employmentandinfrastructure‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)Recreationandtourism‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)Landuse‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)Othermarineuses‐‐ ‐‐ ‐‐ ‐‐ ‐‐  ‐‐ ‐‐ ‐‐ ‐‐X(6)WCD=worstcasedischarge.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 7 Table 2 Footnotes and Applicability:

(1) Activities that may affect a marine sanctuary or topographic feature. Specifically, if the well, rig site, or any

anchors will be on the seafloor within the following:

(a) 4

‐ mi zone of the Flower Garden Banks, or the 3

‐ mi zone of Stetson Bank;

(b) 1,000

‐ m, 1

‐ mi, or 3

‐ mi zone of any topographic feature (submarine bank) protected by the Topographic

Features Stipulation attached to an Outer Continental Shelf (OCS) lease;

(c) Essential Fish Habitat (EFH) criteria of 500 ft from any no

‐ activity zone; or

(d) Proximity of any submarine bank (500

‐ ft buffer zone) with relief greater than 2 m that is not protected by

the Topographic Features Stipulation attached to an OCS lease.

 Not applicable. The lease is not within or near a marine sanctuary, topographic feature, or

no

‐ activity zone. There are no submarine banks in the blocks.

(2) Activities with any bottom disturbance within an OCS lease block protected through the Live Bottom

(Pinnacle Trend) Stipulation attached to an OCS lease.

 The Live Bottom (Pinnacle Trend) Stipulation is not applicable to the lease area.

(3) Activities within any Eastern Gulf OCS block where seafloor habitats are protected by the Live Bottom

(Low

‐ Relief) Stipulation attached to an OCS lease.

 The Live Bottom (Low

‐ Relief) Stipulation is not applicable to the lease area.

(4) Activities on blocks designated by the BOEM as being in water depths 300 m or greater.

 No impacts on high

‐ density deepwater benthic communities are anticipated. There are no features

indicative of high

‐ density chemosynthetic communities or coral communities within 610 m (2,000 ft) of

any drilling mud/cuttings discharge location.

(5) Exploration or production activities where H 2 S concentrations greater than 500 ppm might be encountered.

 Anadarko is requesting that BOEM classify the area as a zone where the absence of H 2 S has been

confirmed.

(6) All activities that could result in an accidental spill of produced liquid hydrocarbons or diesel fuel that you

determine would impact these environmental resources. If the proposed action is located a sufficient distance

from a resource that no impact would occur, the EIA can note that in a sentence or two.

 Accidental hydrocarbon spills could affect the resources marked (X) in the matrix, and impacts are

analyzed in Section C

.

(7) All activities that involve seafloor disturbances, including anchor emplacements, in any OCS block designated

by the BOEM as having high

‐ probability for the occurrence of shipwrecks or prehistoric sites, including such

blocks that will be affected that are adjacent to the lease block in which your planned activity will occur. If the

proposed activities are located a sufficient distance from a shipwreck or prehistoric site that no impact would

occur, the EIA can note that in a sentence or two.

 No impacts on archaeological resources are expected. The lease area is not on the list of high

‐ probability

blocks for shipwrecks and is well beyond the 60

‐ m depth contour used by the BOEM as the seaward

extent for prehistoric archaeological site potential in the Gulf of Mexico.

(8) All activities that you determine might have an adverse effect on endangered or threatened marine mammals

or sea turtles or their critical habitats.

 IPFs that may affect marine mammals, sea turtles, or their critical habitats include drilling rig presence

and emissions, support vessel and helicopter traffic, and accidents. See Section C

.

(9) Production activities that involve transportation of produced fluids to shore using shuttle tankers or barges.

 Not applicable.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 8 

## A.2 Physical Disturbance to the Seafloor

In water depths of 600 m (1,969 ft) or greater, DP drillships and DP semisubmersibles disturb

only a very small area of the seafloor around the wellbore (SHL) where the bottom template and

blowout preventer are located. Depending on the specific well configuration, this area is

generally about 0.25 ha (0.62 ac).

Anchoring causes physical compaction of the seafloor beneath the anchor, and chains or lines

can disturb the bottom as well as resuspend sediments as they move about. A disturbed area

on the sea bottom, called the “anchor sweep,” forms by the swing arc of anchor lines scraping

across bottom within the range allowed by the anchoring system configuration

(BOEMRE, 2011a). Anchored semisubmersibles disturb approximately 2 to 3 ha (5 to 7 ac) of

seafloor, depending on the number of anchors and their mooring configurations (MMS, 2007a).



## A.3 Air Pollutant Emissions

Air pollutant emissions are calculated in EP Section G and are estimated to be insignificant.

Offshore air pollutant emissions will result from operations of the drilling rig, as well as service

vessels and helicopters. These emissions occur mainly from combustion of diesel fuel. The

combustion of fuels occurs on diesel

‐ powered generators, pumps, or motors and from lighter

fuel motors. Primary air pollutants typically associated with OCS activities are suspended

particulate matter (PM), sulfur oxides (SO

x ), nitrogen oxides (NO

x ), volatile organic compounds

(VOCs), and carbon monoxide (CO).

The Air Quality Emissions Report prepared in accordance with BOEM requirements

demonstrates that the projected emissions are below exemption levels set by the applicable

regulations in 30 CFR 250.303. Based on this and the distance to shore, it can be concluded that

the emissions will not significantly affect the air quality of the onshore area for any of the

criteria pollutants. No further analysis or control measures are required.



## A.4 Effluent Discharges

Effluent discharges are summarized in SEP Section F

. All offshore discharges will be in

accordance with requirements of the National Pollutant Discharge Elimination System (NPDES)

General Permit No. GEG460000 issued by the U.S. Environmental Protection Agency (USEPA).

Any discharges will be in compliance with the permit terms and monitored as required by the

permit.

Water

‐ based drilling muds and cuttings will be released at the seafloor during the initial well

intervals before the marine riser that allows their return to the surface is set. Excess cement

slurry will also be released at the seafloor during casing installation for the riserless portion of

the drilling operations. Synthetic

‐ based drilling muds (SBMs) will be collected on the rig and

either reused by the vendor, or transported to Fourchon for recycling and/or disposal in an

approved facility. Cuttings wetted with SBMs will be discharged to the seafloor in accordance

with the NPDES permit.

Other effluent discharges in accordance with the NPDES permit will include excess cement,

non

‐ contact cooling water, treated sanitary and domestic wastes, deck drainage, desalination

unit brine, uncontaminated fresh water and seawater, and ballast water.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 9 

## A.5 Water Intake

Seawater will be drawn from the ocean for once

‐ through, non

‐ contact cooling of machinery on

the drilling rig. Section 316(b) of the Clean Water Act requires NPDES permits to ensure that the

location, design, construction, and capacity of cooling water intake structures reflect the best

technology available to minimize adverse environmental impact from impingement and

entrainment of aquatic organisms. The current NPDES General Permit No. GEG460000 does not

specify requirements for existing facilities (those that started construction before 16 July 2006).

The rigs being considered for use for activities described in this SEP are not “new” facilities as

defined by the NPDES permit and therefore are not subject to the cooling water intake

regulations.



## A.6 Onshore Waste Disposal

Wastes generated during drilling are tabulated in SEP Section F

. Approximately 50 bbl of trash

will be generated each month of operations, or a total of 1458 bbl over the life of this project.

The trash will be transported in disposal bags to shore, where it will be picked up by municipal

operators for final disposal in accordance with applicable regulations.



## A.7 Marine Debris

Anadarko will comply with all regulations relating to solid waste handling and disposal, including

the International Convention for the Prevention of Pollution from Ships (MARPOL 73/78)

Annex V requirements and USEPA and U.S. Coast Guard (USCG) regulations, as well as those of

the BOEM. For example, BOEM regulations at 30 CFR 250.300(a) and (b)(6) prohibit operators

from deliberately discharging containers and other similar materials (i.e., trash and debris) into

the marine environment, and 30 CFR 250.300(c) requires durable identification markings on

equipment, tools, and containers (especially drums), and other material. USEPA and USCG

regulations require operators to become proactive in avoiding accidental loss of solid waste

items by developing waste management plans, posting informational placards, manifesting trash

sent to shore, and using special precautions such as covering outside trash bins to prevent

accidental loss of solid waste. In addition to the regulations in 30 CFR 250, BSEE issued

NTL 2012

‐ BSEE

‐ G01, which instructs operators to exercise caution in the handling and disposal

of small items and packaging materials, requires the posting of placards at prominent locations

on offshore vessels and structures, and mandates a yearly marine trash and debris awareness

training and certification process.



## A.8 Support Vessel and Helicopter Traffic

Anadarko’s primary shorebase facility will be located in Fourchon, Louisiana. The primary

helicopter base will be located in Houma, Louisiana. No terminal expansion or construction is

planned at the locations.

The project will be supported by one crew boat and one supply vessel. The crew boat will make

three round

‐ trips per week, and the supply vessel will make two round

‐ trips per week. The

boats typically will move to the project area via the most direct route from the shorebase.

A helicopter will make ten round

‐ trips per week between the drilling rig and the heliport. The

helicopter will be used to transport personnel and small supplies and will normally take the

most direct route of travel between the shorebase and the lease area when air traffic andEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 10 weather conditions permit. Helicopters typically maintain a minimum altitude of 213 m (700 ft)

while in transit offshore, 305 m (1,000 ft) over unpopulated areas or across coastlines, and

610 m (2,000 ft) over populated areas and sensitive habitats such as wildlife refuges and park

properties.



## A.9 Accidents

A.9.1 Types of Accidents Evaluated

The analysis in this EIA focuses on two potential accidents:

 A small fuel spill, which is the most likely type of spill during OCS exploration activities; and

 The WCD for this EP, which is an oil spill resulting from an uncontrolled blowout.

The following subsections summarize assumptions about the sizes and fates of these spills, as

well as Anadarko’s spill response plans. Impacts are analyzed in Section C

.

MMS (2007b), BOEMRE (2011a), and BOEM (2012) analyze three other types of accidents:

chemical spills, vessel collisions, and loss of well control. These types of accidents are discussed

briefly in Section A.9.4

.



### A.9.2 Small Fuel Spill

Spill Size. According to the analyses in MMS (2007b) and BOEM (2012), the most likely type of

small spill (<1,000 bbl) as a result of OCS activities is a minor diesel fuel spill. Historically, most

diesel spills have been <1 bbl, and this size is predicted to be the most common in ongoing and

future OCS activities in the Western and Central Gulf of Mexico Planning Areas. As the spill size

increases, the incident rate declines dramatically (MMS, 2007b; BOEMRE, 2011a; BOEM 2012).

The average size for spills <1 bbl is 0.07 bbl, and the median size for spills of 1 to 10 bbl is 3 bbl

(MMS, 2007b). For this analysis, a small diesel fuel spill of 3 bbl is assumed. Operational

experience suggests that the most likely cause of such a spill would be a hose rupture resulting

in the loss of the contents of a fuel transfer hose, which is less than 3 bbl.

Spill Fate. The fate of a small fuel spill in the lease area would depend on meteorological and

oceanographic conditions at the time, as well as the effectiveness of spill response activities.

However, given the open ocean location of the lease area and response actions, it is expected

that impacts from a small spill would be minimal (BOEMRE, 2011a; BOEM, 2012).

The water

‐ soluble fractions of diesel are dominated by two

‐ and three

‐ ringed polycyclic

aromatic hydrocarbons (PAHs), which are moderately volatile (National Research Council, 2003).

The constituents of these oils are light to intermediate in molecular weight and can be readily

degraded by aerobic microbial oxidation. Due to its light density, diesel will not sink to the

seafloor. Diesel dispersed in the water column can adhere to suspended sediments, but this

generally occurs only in coastal areas with high suspended solids loads (National Research

Council, 2003) and would not be expected to occur to any appreciable degree in offshore waters

of the Gulf of Mexico. Diesel oil is readily and completely degraded by naturally occurring

microbes (National Oceanic and Atmospheric Administration [NOAA], 2006).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 11 For purposes of this EIA, the fate of a small diesel fuel spill was estimated using NOAA’s

Automated Data Inquiry for Oil Spills 2 (ADIOS2) model. This model uses the physical properties

of oils in its database to predict the rate of evaporation and dispersion over time, as well as

changes in the density, viscosity, and water content of the product spilled. It is estimated that

over 90% of a small diesel spill would be evaporated or dispersed within 24 hours. The area of

the sea surface with diesel fuel on it during this 24

‐ hour period would range from 0.5 to 5 ha

(1.2 to 12 ac) depending on sea state and weather conditions.

The ADIOS2 results, coupled with spill trajectory information discussed below for a large spill,

indicate that a small fuel spill would not have any impacts on coastal or shoreline resources.

The lease area is 120 miles (194 km) from the nearest shoreline (Texas). Modeling results

discussed below indicate that a spill in the lease area would have an 18% or less probability of

reaching the coastal areas of Texas within 10 days after a spill. By that time, essentially 100% of

a small fuel spill would have been dispersed or evaporated by natural processes, without taking

into account Anadarko’s response measures. MMS (2007b) similarly concluded that spills

<1,000 bbl are not expected to persist as a slick on the surface of the water beyond a few days

and are unlikely to make landfall or reach coastal waters prior to breaking up. MMS (2007b)

noted that this conclusion is supported by a previous analysis of three

‐ day trajectory model

runs, previous weathering analyses, and historical records of spill incidents.

Spill Response. In the unlikely event the shipboard prevention procedures fail to prevent a fuel

spill, response equipment and trained personnel would be activated so that any spill effects

would be localized and would result only in short

‐ term environmental consequences.

SEP Section 9b provides a detailed discussion of Anadarko’s response to a spill.



### A.9.3 Crude Oil Spill (Worst Case Discharge)

Spill Size. In accordance with requirements of NTL 2010

‐ N06, Anadarko has estimated a

WCD for EB 690 of 172,789 barrels of oil per day (BOPD). The estimated maximum total time to

drill a relief well is 70 days. This estimate includes time to suspend current operations on an

existing well, mobilization of another rig, transport of the relief

‐ drilling rig to the blowout

location, and 49 days to drill the relief well and perform kill operations. The total estimated

volume of a spill over this duration would be 12,095,203 barrels of oil. The detailed analysis of

this calculation can be found in SEP Section H

.

Historically, blowouts are rare events and most do not result in oil spills. Holand (1997)

estimated a probability of 0.0021 for a deep drilling blowout during exploration drilling based on

U.S. Gulf of Mexico data. An updated analysis using the SINTEF database estimates a blowout

frequency of 0.0017 per exploratory well for non

‐ North Sea locations (International Association

of Oil & Gas Producers, 2010). As noted by MMS (2007b), from 1992 to 2005, half of blowouts

lasted less than half a day, and fewer than 10% of blowouts resulted in spilled oil. BOEM is in

the process of updating these spill frequency estimates to include the recent Macondo event;

however, significant changes to the spill rates for the entire OCS are not anticipated

(BOEMRE, 2011a; BOEM, 2012). As noted in the Introduction

, the baseline risk of a catastrophic

blowout is estimated to be once every 26 years (BOEMRE Interim Final Drilling Safety Rule,

75 FR 63365, 10 October 2010).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 12 Included in SEP Section H are Anadarko’s calculations and information as required by

NTL 2010

‐ N06, including descriptions of measures to prevent a blowout, reduce the likelihood of

a blowout, and conduct effective and early intervention in the event of a blowout. Anadarko

will also comply with NTL 2010

‐ N10 and the Interim Final Drilling Safety Rule, which specifies

additional safety measures for OCS activities.

Spill Trajectory. The fate of a large oil spill in the lease area would depend on meteorological

and oceanographic conditions at the time. The Oil Spill Risk Analysis (OSRA) model is a

computer simulation of oil spill transport that uses realistic data for winds and currents to

predict spill fate. Although this model has received some criticism recently (Earthjustice, 2011),

it is still the most widely scientifically accepted model for estimating the fate of small fuel spills.

The primary criticism of the OSRA model results as provided in Ji et al. (2004) was that the

model did not evaluate the fate of a spill over time periods longer than 30 days, nor does it

predict the fate of a release that continues over a period of weeks or months, as in the

Macondo incident. Also as noted by Ji et al. (2004), the OSRA model does not take into account

the chemical composition or biological weathering of oil spills, the spreading and splitting of oil

spills, or spill response activities. The model does not assume a particular spill size but has

generally been used by the BOEMRE/MMS to evaluate contact probabilities for spills greater

than 1,000 bbl.

To address this criticism, a special OSRA run was conducted for the recent BOEM Central and

Western Gulf of Mexico Planning Area Supplemental EISs (BOEMRE, 2011a; BOEM, 2012) in

order to estimate the impacts of a possible future catastrophic long

‐ duration oil spill. In this

OSRA model run a hypothetical high volume, long

‐ duration oil spill was assumed to have

occurred, and the analysis emphasized modeling a spill that continued for 90 consecutive days,

with each trajectory tracked for up to 120 days.

The OSRA model run for this revised analysis was conducted for five hypothetical launch points

in the Central and Western Gulf of Mexico Planning Areas. These launch points were

deliberately located in areas identified as having a high possibility of containing large oil

reserves.

The five launch point areas were as follows:

1. Central Gulf of Mexico shelf area west of the Mississippi River (28.98660°

N latitude, 92.17851° W longitude);

2. Central Gulf of Mexico shelf area east of the Mississippi River (29.91388° N latitude,

88.15338° W longitude);

3. Central Gulf of Mexico slope area (27.31998° N latitude, 90.22203° W longitude);

4. Western Gulf of Mexico shelf area (27.55423° N latitude, 96.76627° W longitude); and

5. Western Gulf of Mexico slope area (27.51367° N latitude, 94.51836° W longitude).

The results for Launch Point 5, the nearest location to this project area, are presented in

Table 3

.

OSRA is a preliminary risk assessment model. In the event of an actual oil spill, real

‐ time

monitoring and trajectory modeling would be conducted using current and wind data available

from the rigs and permanent production structures in the area. Satellite and aerial monitoring

of the plume and real

‐ time trajectory modeling using wind and current data would continue onEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 13 a daily basis to help position equipment and human resources throughout the duration of any

major spill or uncontrolled release.

Table 3. Conditional probabilities expressed as percent chance that an oil spill starting at

Launch Point 5 will contact a certain parish, county, or coastline within 120 days

(Modified from: BOEM, 2012).

Season Winter Spring Summer Fall

Day 3 10 30 120 3 10 30 120 3 10 30 120 3 10 30 120

County or Parish Percent Chance

Cameron, Texas

‐‐  ‐‐ 2 4

‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐ 2 3

‐‐  ‐‐ 3 5

Willacy, Texas

‐‐  ‐‐ 1 4

‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐ 2 3

‐‐  ‐‐ 2 3

Kenedy, Texas

‐‐ 1 8 14

‐‐  ‐‐ 1 1

‐‐  ‐‐ 4 7

‐‐  ‐‐ 6 9

Kleberg, Texas

‐‐  ‐‐ 5 7

‐‐ 1 2 2

‐‐  ‐‐ 1 3

‐‐  ‐‐ 4 5

Nueces, Texas

‐‐ 1 5 9

‐‐ 1 2 2

‐‐  ‐‐ 1 1

‐‐  ‐‐ 3 5

Aransas, Texas

‐‐ 1 5 10

‐‐  ‐‐ 3 3

‐‐  ‐‐ 2 3

‐‐  ‐‐ 4 6

Calhoun, Texas

‐‐ 2 10 20

‐‐ 3 11 12

‐‐  ‐‐ 7 9

‐‐ 1 5 7

Matagorda, Texas

‐‐ 1 8 14

‐‐ 18 29 30

‐‐ 2 12 21

‐‐ 2 9 15

Brazoria, Texas

‐‐  ‐‐ 3 4

‐‐ 9 13 13

‐‐  ‐‐ 7 12

‐‐ 1 4 6

Galveston, Texas

‐‐ 1 2 4

‐‐ 3 11 13

‐‐  ‐‐ 5 12

‐‐ 1 2 3

Jefferson, Texas

‐‐  ‐‐  ‐‐ 1

‐‐  ‐‐ 12 15

‐‐  ‐‐ 1 4

‐‐  ‐‐  ‐‐ 1

Cameron, Louisiana

‐‐  ‐‐  ‐‐ 1

‐‐ 1 5 6

‐‐  ‐‐ 6 8

‐‐  ‐‐  ‐‐  ‐‐

Vermilion, Louisiana

‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐ 2 3

‐‐  ‐‐ 1 2

‐‐  ‐‐  ‐‐  ‐‐

Plaquemines, Louisiana

‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐  ‐‐ 1

‐‐  ‐‐  ‐‐  ‐‐

“

‐‐ ”

= Values <1.0%. Areas where there is <0.5% chance of contact within 120 days are not shown.

Weathering. Following an oil spill, several physical, chemical, and biological processes,

collectively called weathering, interact to change the physical and chemical properties of the oil,

influencing potential effects to marine organisms and ecosystems. The most important

weathering processes include spreading, evaporation, dissolution, dispersion into the water

column, formation of water

‐ in

‐ oil emulsions, photochemical oxidation, microbial degradation,

adsorption to suspended particulate matter, and stranding on shore or sedimentation to the

seafloor (National Research Council, 2003).

Weathering decreases the concentration of oil and produces changes in its chemical

composition, physical properties, and toxicity. The more toxic, light aromatic and aliphatic

hydrocarbons are lost rapidly by evaporation and dissolution from a slick on the water surface.

Evaporated hydrocarbons are degraded rapidly by sunlight. Biodegradation of oil on the water

surface and in the water column by marine bacteria removes first the n

‐ alkanes and then the

light aromatics from the oil. Other petroleum components are biodegraded more slowly.

Photo

‐ oxidation attacks mainly the medium and high molecular weight PAHs in the oil on the

water surface.

Spill Response. BOEM issued recent NTLs following the Macondo spill that clarify additional

oil

‐ spill prevention and response planning requirements. These NTLs are summarized in Table 2

, and additional BOEM (2012) guidance is provided below.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 14 NTL 2010

‐ N10

– Statement of Compliance with Applicable Regulations and Evaluation of

Information Demonstrating Adequate Spill Response and Well Containment Resources :

This NTL, effective 8 November 2010, applies only to operators conducting operations using

subsea or surface BOPs on floating facilities. It requires that lessees and operators must

submit a statement signed by an authorized company official with each well permit

application indicating that they will conduct all of their authorized activities in compliance

with all applicable regulations, including the Increased Safety Measures Regulations at

75 FR 63346. The NTL also informs lessees that BOEM will evaluate whether or not the

operator has submitted adequate information demonstrating that it has access to and can

deploy surface and subsea containment resources that would be adequate to promptly

respond to a blowout or other loss of well control. The NTL notifies the operator that

BOEM intends to evaluate the adequacy of each operator to comply in the operator’s

current OSRP; therefore, there is an incentive for voluntary compliance.

NTL 2010

‐ N06

– Information Requirements for Exploration Plans, Development and

Production Plans, and Development Operations Coordination Documents on the OCS:

This NTL, effective 18 June 2010, explains the procedures for the lessee or operator to

submit supplemental information for new or previously submitted EPs, Development and

Production Plans

, or Development Operations Coordination Documents. The required

supplemental information includes the following: 1) a description of the blowout scenario as

required by 30 CFR 254(b) and 254(h); 2) a description of their assumptions and calculations

used in determining the volume of the WCD required by 30 CFR 254.26; and 3) a description

of the measures proposed that would enhance the ability to prevent a blowout, reduce the

likelihood of a blowout, and conduct effective and early intervention in the event of a

blowout, including arrangements for drilling relief wells and any other measures proposed.

The early intervention methods of the third requirement could include the surface and

subsea containment resources that BOEM announced in NTL 2010

‐ N10, which states that

BOEM will review to ensure that the measures are adequate to promptly respond to a

blowout or other loss of well control.

Anadarko submitted an updated Gulf of Mexico Regional OSRP to BOEMRE on 21 July

2011. In addition, Anadarko submitted a Regional OSRP Certification Letter per 30 CFR 254.2 (b)

to BOEMRE on 21 July 2011. The Certification Letter was accepted by BOEMRE on 27 July 2011.

Additional updates have been submitted to BSEE for review since then. The OSRP provides a

detailed plan for Anadarko to respond to rapidly and effectively manage oil spills that may result

from drilling and production operations. The OSRP contains detailed information on “Quick

Response” procedures including

 responsibilities of all Anadarko and contract personnel to report any observed discharge

from known or unknown sources;

 procedures to locate and determine the size of a discharge; and

 contact information for alerting the spill management team complete with names, phone

numbers, and locations.

In the event of a WCD, Anadarko has access to surface and subsea response/containment

capabilities that could be implemented through various organizations under contract.

Anadarko's primary spill response equipment provider is Clean Gulf Associates (CGA).

CGA has four skimming vessels capable of operating in shallow waters and offshore/nearshore

areas. These vessels have oleophilic brush pack skimming systems operating in troughs builtEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 15 into the hulls below deck storage and marine electronics packages including marine, aircraft,

and company

‐ frequency radios, radar, moving map plotters, GPSs, satellite phones, and depth

finders. In addition, there are three Marco skimmers and two Egmopol skimmers that can be

used for inland or nearshore skimming. CGA also offers nine Fast Response Systems staged

throughout the Gulf of Mexico available for offshore use.

The CGA high

‐ volume open sea skimmer (HOSS) barge consists of a skimming system built into

an oil recovery barge. There are four 1,000

‐ bbl recovered oil storage tanks built into the hull

where oil can be separated and offloaded. Skimming operations are conducted from the control

room overlooking the skimmer deck. The estimated daily recovery capacity for the HOSS barge

is approximately 43,000 bbl.

CGA is currently adding to its equipment stockpile and has recently acquired 11 sets of

Koseq skimming arms and two Aqua Guard skimmers. In addition, an x

‐ band radar/infrared

tracking system is installed on the HOSS barge. Additional CGA equipment can be referenced on

the website: http://www.cleangulfassoc.com/

.

Anadarko also has a contract with the Marine Spill Response Corporation (MSRC) for additional

spill response equipment. MSRC has a dedicated fleet for the Atlantic/Gulf of Mexico region and

additional available equipment staged throughout the U.S. The equipment MSRC staged

throughout the Gulf of Mexico includes 7 oil spill response vessels (OSRVs), 2 fast response

vessels (FRVs), 5 oil spill response barges (OSRBs), 5 platform supply vessels (PSVs), and

15 shallow water barges. Various equipment is outfitted with x

‐ band and infrared technology.

MSRC recently completed a large expansion of its resources and capability in the Gulf of Mexico,

with particular focus on deepwater. The expansion is known as “Deep Blue.” Additional MSRC

capabilities and a complete equipment listing is available on

‐ line at: http://www.msrc.org/

.

Anadarko also is a member of the Marine Well Containment Company (MWCC). In the event of

an incident, MWCC can provide a 15,000

‐ psi single ram capping stack and dispersant injection

capability. MWCC can also install and operate the interim containment system, including subsea

flowlines, manifold, and risers. The interim system is engineered to be used in depths up to

3,048 m (10,000 ft) and has the capacity to contain 60,000 barrels of liquid per day (BLPD)

(and 120 million standard cubic feet per day [MMSCFD] of gas) with potential for expansion.

See SEP Section H for a detailed description of Anadarko’s site

‐ specific response to the WCD for

this plan.



### A.9.4 Other Accidents Not Analyzed in Detail

MMS (2007b) discusses three other types of accidents: chemical spills, vessel collisions, and loss

of well control. The information from the EIS on these topics remains valid and is incorporated

by reference into this document. These accidents are discussed briefly below along with a

hydrogen sulfide (H

2 S) release. There are no other site

‐ specific issues raised by well drilling

proposed in this SEP.

Chemical Spills. Chemicals are stored and used to condition drill muds and during production

and in well completions, stimulation, and workover procedures. The relative quantity of their

use is reflected in the largest volumes spilled. Completion fluids are the largest quantity used

and comprise the largest releases. Between 5 and 15 chemical spills are anticipated each year,East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 16 with the majority being <50 bbl in size. The most common chemicals spilled are methanol,

ethylene glycol, and zinc bromide. Additional production chemicals are needed in deepwater

operations where gas hydrates tend to form. Spill volumes are anticipated to remain about the

same, but spill frequency can be expected to decrease because of advances in subsea processing

(BOEMRE, 2011a; BOEM, 2012).

Riser Disconnect SBM Spills. In deepwater drilling, SBMs are preferred over petroleum oil

‐ based

muds (OBMs) due to the superior environmental properties of SBMs. The synthetic base fluid

used in SBMs are less toxic to the marine environment and have the potential to biodegrade.

SBMs have been used in the Gulf of Mexico since the mid

‐ 1990s, and between 5 and 20 SBM

releases are anticipated each year as a result of offshore drilling programs. The majority of

these releases are <50 bbl in size, but accidental riser disconnects may result in the release of

medium (238 to 2,380 bbl) to large (>2,381 bbl) quantities of drilling fluids. Riser disconnect

accidents are of particular concern when SBMs are in use (BOEM, 2011b).

Vessel Collisions. BOEM data show that from 1996 to 2009 there were 226 OCS

‐ related

collisions. Most collision mishaps are the result of service vessels colliding with platforms or

vessel collisions with pipeline risers. Approximately 10% of vessel collisions with platforms in

the OCS resulted in diesel spills, and in several collision incidents fires resulted from

hydrocarbon releases. To date, the largest diesel spill associated with a collision occurred in

1979 when an anchor

‐ handling boat collided with a drilling platform in the Main Pass leasing

area, spilling 1,500 bbl. Diesel fuel is the product most frequently spilled, although oil, natural

gas, corrosion inhibitor, hydraulic fluid, and lube oil have also been released as the result of

vessel collisions. Human error accounts for approximately half of all reported vessel collisions

from 2006 to 2009. As summarized in MMS (2007b) and BOEM (2012), vessel collisions

occasionally occur during routine operations. Some of these collisions have caused spills of

diesel fuel or chemicals. Anadarko will comply with all USCG

‐ and BOEM

‐ mandated safety

requirements to minimize the potential for vessel collisions.

Loss of Well Control. A loss of well control is the uncontrolled flow of a reservoir fluid that may

result in the release of gas, condensate, oil, drilling fluids, sand, or water. Loss of well control is

a broad term that includes very minor up to the most serious well control incidents, while

blowouts are considered to be a subset of more serious incidents with greater risk of oil spill or

human injury (MMS, 2007b). Loss of well control may result in the release of synthetic drilling

fluid or loss of oil. Anadarko has a robust system in place to prevent loss of well control.

Measures to prevent a blowout, reduce the likelihood of a blowout, and conduct effective and

early intervention in the event of a blowout are described in SEP Section H as required by

NTL 2010

‐ 06. The potential for a loss

‐ of

‐ well

‐ control event will be minimized by adhering to the

requirements of applicable regulations such as the Interim Final Drilling Safety Rule and

NTL 2010

‐ N10, which specify additional safety measures for OCS activities.

H 2 S Release. EB 645 was determined as “H

2 S absent” under a previously approved Initial

Exploration Plan. Anadarko has requested that BOEM classify EB 645, 689, and 690 as a "zone

where the absence of H 2 S has been confirmed.”East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 17 

## B. Affected Environment

The lease area is in the central Gulf of Mexico, 120 miles (194 km) from the nearest shoreline

(Texas), and 287 miles (463 km) from the onshore support base at Fourchon, Louisiana

( Figure 2 ).

Based on the site clearance letters by Geoscience Earth and Marine Services Inc. (GEMS, 2012)

the depths of the proposed wellsites range from 1,156 to 1,262 m (3,794 to 4,139 ft). There is

no evidence of significant seafloor or subsurface faulting, fluid expulsion features, or

high

‐ density deepwater benthic communities near the wellsites.

A detailed description of the regional affected environment is provided in recent lease sale EISs,

including meteorology, oceanography, geology, air and water quality, benthic communities,

threatened and endangered species, biologically sensitive resources, archaeological resources,

socioeconomic conditions, and other marine uses (MMS, 2007b, 2008). These regional

descriptions remain valid and are incorporated by reference. General background information is

presented below, and brief descriptions of each potentially affected resource, including

site

‐ specific and/or new information if available, are presented in Section C

.

The Macondo spill resulted in impacts to water quality in the area of the spill. In addition to the

oil slick on the sea surface, plumes of submerged oil droplets were produced when subsea

dispersants were applied at the wellhead (Camilli et al., 2010; Hazen et al., 2010; Joint Analysis

Group, 2010a,b,c). Despite limited information on the water quality of deep water, it is clear

that the condition of the offshore waters of the Gulf of Mexico was altered by the Macondo

event. Various monitoring efforts and environmental studies are in progress, but it is not

currently possible to precisely estimate the long

‐ term impacts the spill will have on offshore

water quality (BOEMRE, 2011a; BOEM, 2012).EastBreaksBlocks645,689,and690May2012EnvironmentalImpactAnalysisforSupplementalExplorationPlanPage18Figure2.Bathymetricmapoftheleaseareashowingproposedwellsurfaceholelocations.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 19 The lease area is located approximately 385 miles (620 km) west

‐ southwest of the Macondo spill

site. Based on an analysis of satellite imagery (ESRI, 2010), the surface slick did not extend over

the lease area; therefore, existing water quality in the lease area was not likely to have been

affected. Prior to the Macondo incident, water quality in deep, offshore waters of the Gulf of

Mexico was expected to be good, with low levels of contaminants (Kennicutt, 2000). Based on

the information currently available, there is no reason to expect any change in water quality

conditions in the lease area from those predicted in the recent lease sale EISs (MMS, 2007b,

2008; BOEMRE, 2011a, BOEM, 2012).



## C. Impact Analysis

This section analyzes the potential direct and indirect impacts of routine activities and accidents.

Impacts have been analyzed extensively in recent lease sale EISs for the Central and Western

Gulf of Mexico Planning Areas (MMS, 2007b, 2008; BOEMRE, 2011a; BOEM 2012) as well as the

Environmental Assessment (EA) for Gulf of Mexico deepwater operations and activities

(MMS, 2000). The information in these documents is incorporated by reference. Potential

site

‐ specific issues are addressed in this section.



## C.1 Physical/Chemical Environment

C.1.1 Air Quality

There are no site

‐ specific air quality data for the project area due to the distance from shore.

Because of the distance from shore

‐ based pollution sources and the lack of sources offshore, air

quality at the wellsites is expected to be good. The attainment status of Federal OCS waters is

unclassified because there is no provision in the Clean Air Act for classification of areas outside

state waters (MMS, 2007b).

As noted earlier, based on calculations made pursuant to applicable regulations, emissions from

drilling activities are not expected to be significant as they are below exemption levels.

Therefore, the only potential effects to air quality would be from routine air pollutant emissions,

a small fuel spill, and a large oil spill (WCD).

BOEM has reexamined the analysis for air quality presented in MMS (2007b, 2008) based on

additional information and in consideration of the Macondo oil spill event. No substantial new

information was found that would alter the potential impacts on air quality presented in

previous lease sale EISs (BOEMRE, 2011a; BOEM, 2012).



### Impacts of Air Pollutant Emissions

Air pollutant emissions are the only routine IPF likely to affect air quality. Offshore air pollutant

emissions will result from the drilling rig operations, helicopters, and service vessels. These

emissions occur mainly from combustion or burning of diesel fuel. The combustion of fuels

occurs primarily on diesel

‐ powered generators, pumps, or motors and from lighter fuel motors.

Primary air pollutants typically associated with OCS activities are suspended PM, SO

x , NO

x , VOCs,

and CO. Emissions of pollutants into the atmosphere from these activities are not projected to

have significant effects on onshore air quality because of the prevailing atmospheric conditions,East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 20 emission rates and heights, and resulting pollutant concentrations. As the BOEM found in the

lease sale EISs, the incremental contribution of activities similar to Anadarko’s proposed

activities to the cumulative impacts is not significant and will not cause or contribute to a

violation of any National Ambient Air Quality Standard (NAAQS) (MMS, 2007b, 2008). Since the

BOEM completed the lease sale EISs, the USEPA has adopted a new short

‐ term NAAQS for

nitrogen dioxide (NO

2 ). The standard has not yet been implemented in the Gulf Coast states,

but given the levels of expected emissions and the distance of the project from shore, emissions

from the activities described in Anadarko’s proposed SEP are not likely to contribute to

violations of any NAAQS onshore.

Carbon dioxide (CO

2 ) and methane (CH

4 ) emissions from the project would constitute a small

incremental contribution to greenhouse gas emissions from all OCS activities. According to the

Programmatic EIS (MMS, 2007a), estimated CO 2 emissions from all OCS activities in the

2007

‐ 2012 leasing program are about 0.08% to 0.016% of the global CO 2 emissions from fossil

fuel combustion. Greenhouse gas emissions may contribute to climate change, with important

effects on temperature, rainfall, frequency of severe weather, ocean acidification, and sea level

rise (Intergovernmental Panel on Climate Change, 2007). Greenhouse gas emissions from this

proposed project represent a negligible contribution to the total greenhouse gas emissions from

reasonably foreseeable activities in the Gulf of Mexico area and would not significantly alter any

of the climate change impacts evaluated in the lease sale EIS (MMS, 2007b) or Programmatic EIS

(MMS, 2007a).

Due to the distance from shore, routine operations in the project area are not expected to have

any impact on air quality conditions along the coast, including nonattainment areas. As noted in

the lease sale EIS (MMS, 2007b), emissions of air pollutants from routine activities in the Central

Gulf of Mexico Planning Area are projected to have minimal impacts to onshore air quality

because of the prevailing atmospheric conditions, emission heights, emission rates, and the

distance of these emissions from the coastline. The Air Quality Emissions Report

(see EP Section G ) prepared in accordance with BOEM requirements shows that the projected

emissions are below exemption levels; therefore, according to 30 CFR 250.303, the emissions

will not significantly affect the air quality of the onshore area for any of the criteria pollutants.

No further analysis or control measures are required.

The Breton Wilderness Area, which is part of the Breton National Wildlife Refuge (NWR), is

designated under the Clean Air Act as a Prevention of Significant Deterioration (PSD) Class I air

quality area. The BOEM is required to notify the National Park Service (NPS) and U.S. Fish and

Wildlife Service (USFWS) if emissions from proposed projects may affect the Breton Class I area.

Additional review and mitigation measures may be required for sources within 186 miles

(300 km) of the Breton Class I area that exceed emission limits agreed upon by the administering

agencies (NPS, 2010). The lease area is approximately 354 miles (569 km) from the Breton

Wilderness Area, so air quality impacts on the Wilderness Area are not expected.



### Impacts of a Small Fuel Spill

Potential impacts of a small spill on air quality are expected to be consistent with those analyzed

and discussed in EISs prepared for recent lease sales (MMS, 2007b, 2008; BOEMRE, 2011a;

BOEM, 2012). The probability of a small spill would be minimized by Anadarko’s preventative

measures during routine operations, including fuel transfer. In the unlikely event of a spill,

implementation of Anadarko’s OSRP will reduce the potential impacts. SEP Section H includes aEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 21 detailed discussion of the spill response measures that would be employed. Given the open

ocean location of the lease area, the extent and duration of air quality impacts from a small spill

would not be significant.

A small fuel spill would affect air quality near the spill site by introducing VOCs through

evaporation. The ADIOS2 model (see Section A.9.2 ) indicates that over 90% of a small diesel

spill would be evaporated or dispersed within 24 hours. The area of the sea surface with diesel

fuel on it would range from 0.5 to 5 ha (1.2 to 12 ac) depending on sea state and weather

conditions.

A small fuel spill would not affect coastal air quality because the spill would not be expected to

make landfall or reach coastal waters prior to breaking up (see Section A.9.2 ).



### Impacts of a Large Oil Spill (WCD)

Potential impacts of a large oil spill on air quality are expected to be consistent with those

analyzed and discussed in recent lease sale EISs (MMS, 2007b, 2008; BOEMRE, 2011a;

BOEM, 2012).

A large oil spill (WCD) could potentially affect air quality by introducing VOCs through

evaporation from the slick. The extent and persistence of impacts would depend on the

meteorological and oceanographic conditions at the time and the effectiveness of spill response

measures. Real

‐ time wind and current data from the project area would be available at the

time of a spill and would be used to assess the fate and effects of VOCs released. Additional air

quality impacts could occur if response measures included in situ burning of the floating oil.

Burning would generate a plume of black smoke and result in emissions of NO

x , SO

x , CO, and

PM, as well as greenhouse gases. However, in situ burning would occur only after authorization

from the USEPA.

Due to the lease area location (120 miles [194 km]) from the nearest shoreline (Texas), most air

quality impacts would occur in offshore waters with minimal chance to affect onshore air

quality.



### C.1.2 Water Quality

There are no site

‐ specific water quality data for the lease area. Due to the lease location in

deep, offshore waters, water quality is expected to be good, with low levels of contaminants.

As noted in a recent lease sale EIS (MMS, 2007b), deepwater areas in the northern Gulf of

Mexico are relatively homogeneous with respect to temperature, salinity, and oxygen.

Kennicutt (2000) noted that the deepwater region has little evidence of contaminants in the

dissolved or particulate phases of the water column. However, there are localized occurrences

of natural seepage of oil, gas, and brines in near

‐ surface sediments and up through the water

column.

The lease area is located approximately 385 miles (620 km) from the Macondo spill site. Based

on the general circulation pattern seen in the Gulf of Mexico and satellite imagery (ESRI, 2010),

the surface slick from that discharge did not extend into this lease area during the spill and

water quality within in the lease area was not affected. Water quality in deep, offshore waters

of the Gulf of Mexico is expected to be good, with low levels of contaminants (Kennicutt, 2000).

Based on the information currently available, there is no reason to expect any change in waterEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 22 quality conditions in the lease area from those predicted in the recent lease sale EISs

(MMS 2007b, 2008; BOEMRE, 2011a).

IPFs potentially affecting water quality are effluent discharges and two types of accidents

‐

a small fuel spill and a large oil spill (WCD).



### Impacts of Effluent Discharges

In general, turbid water can be expected to extend between a few hundred meters and several

kilometers down current from the discharge point for water

‐ based drilling muds and cuttings.

SBMs will be collected on the rig and either reused by the vendor, or transported to Fourchon

and onwards to the Newpark base for recycling and/or disposal in an approved facility. Cuttings

wetted with SBMs will be discharged to the seafloor in accordance with the NPDES permit. All

NPDES permit limitations and requirements will be met. There will be no persistent impacts on

water quality in the lease area (National Research Council, 1983; Neff, 1987; Neff et al., 2000).

Treated sanitary and domestic wastes, including those from support vessels, may have a slight

transient effect on water quality in the immediate vicinity of these discharges. All NPDES permit

limitations and requirements and USCG regulations (as applicable) will be met, therefore, little

or no impact on water quality is anticipated.

Deck drainage includes all effluents resulting from rain, deck washings, and runoff from curbs,

gutters, and drains, including drip pans in work areas. Rainwater that falls on uncontaminated

areas of the drilling rig will flow overboard without treatment. However, rainwater that falls on

the drilling rig deck and other areas such as chemical storage areas and places where equipment

is exposed will be collected and oil and water separated to meet NPDES permit requirements.

Based on adherence to permit limits and applicable regulations, little or no impact on water

quality is anticipated.

Other discharges in accordance with the NPDES permit, such as desalination unit brine and

uncontaminated cooling water, fire water, and ballast water are expected to be diluted rapidly,

resulting in little or no impact on water quality.



### Impacts of a Small Fuel Spill

Potential impacts of a small spill on water quality are expected to be consistent with those

analyzed and discussed in recent EISs (MMS, 2007b, 2008; BOEMRE, 2011a; BOEM, 2012). The

probability of a small spill would be minimized by Anadarko’s preventative measures during

routine operations, including fuel transfer. In the unlikely event of a spill, implementation of

Anadarko’s OSRP will potentially help mitigate and reduce the impacts. SEP Section H provides

detail on spill response measures in addition to the summary information provided in this EIA.

Given the open ocean location of the lease area, the extent and duration of water quality

impacts from a small spill would not be significant.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products. The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures. However, it is estimated that over

90% of a small diesel spill would be evaporated or dispersed within 24 hours (see Section A.9.2 ).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 23 The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha (1.2 to 12 ac)

depending on sea state and weather conditions.

The water

‐ soluble fractions of diesel are dominated by two

‐ and three

‐ ringed PAHs, which are

moderately volatile (National Research Council, 2003). The constituents of these oils are light to

intermediate in molecular weight and can be readily degraded by aerobic microbial oxidation.

Due to its light density, diesel will not sink to the seafloor. Diesel dispersed in the water column

can adhere to suspended sediments, but this generally occurs only in coastal areas with high

suspended solid loads (National Research Council, 2003) and would not be expected to occur to

any appreciable degree in offshore waters of the Gulf of Mexico. Diesel oil is readily and

completely degraded by naturally occurring microbes (NOAA, 2006).

A small fuel spill would not affect coastal water quality because the spill would not be expected

to make landfall or reach coastal waters due to both response efforts that would be undertaken

as well as natural attenuation (see Section A.9.2 ).



### Impacts of a Large Oil Spill (WCD)

Potential impacts of a large oil spill on water quality are expected to be consistent with those

analyzed and discussed in recent lease sale EISs (MMS, 2007b, 2008). A large spill would affect

water quality by producing a slick on the water surface and increasing the concentrations of

petroleum hydrocarbons and their degradation products. The extent and persistence of impacts

would depend on the meteorological and oceanographic conditions at the time and the

effectiveness of spill response measures. Most of the oil would be expected to form a slick at

the surface, although new information from the Macondo spill indicates that plumes of

submerged oil droplets can be produced when subsea dispersants are applied at the wellhead

(Camilli et al., 2010; Hazen et al., 2010; Joint Analysis Group, 2010a,b,c). However, dispersants

would be applied only after approval from the USEPA. Small droplets in the water may adhere

to suspended sediment and be removed from the water column (Operational Science Advisory

Team [OSAT], 2010).

Due to the lease area location (120 miles or 194 km from the nearest shoreline [Texas]), it is

expected that most water quality impacts would occur in offshore waters, especially in the

event of a spill lasting less than 30 days ( Table 3 ).



## C.2 Seafloor Habitats and Biota

Water depths at the proposed SHLs range from 1,156 to 1,262 m (3,794 to 4,139 ft). The

seafloor at the proposed drill sites appears to be smooth and featureless; at EB 645 GG it dips to

the west at approximately 0.75 o ; at the other four wellsite it dips at approximately 1.0 o to 3.2 o to

the east (GEMS, 2012).

Based on the absence of hard bottom areas determined by side

‐ scan sonar during the

site clearance survey, the seafloor is expected to consist mainly of soft bottom communities.

The Site Clearance Survey did not identify any features that could support high

‐ density

deepwater benthic communities within 610 m (2,000 ft) of the wellsites. No areas of gaseous

sediments or possible hydrocarbon seepage were defined in the study area, and the presence of

chemosynthetic communities is considered low (GEMS, 2012).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 24 

### C.2.1 Soft Bottom Benthic Communities

There are no site

‐ specific benthic community data from the lease area. However, data from the

Northern Gulf of Mexico Continental Slope Habitats and Benthic Ecology Study (Wei, 2006;

Rowe and Kennicutt, 2009) can be used to describe typical benthic communities in the area.

Table 4 summarizes data from nearby stations in water depth similar to the lease area.

Table 4. Benthic community data from stations near the lease area (Adapted from: Wei, 2006;

Rowe and Kennicutt, 2009).

Station Water

Depth

(m) Abundance

Meiofauna

(individuals/m 2 ) Macroinfauna

(individuals/m 2 ) Megafauna

(individuals/ha)

RW3 1,318 248,752 1,641 195

RW4 1,570 232,842 1,399 762

Meiofaunal and megafaunal abundances from Rowe and Kennicutt (2009); macroinfaunal abundance from

Wei (2006).

Densities of meiofauna (animals passing through a 0.5

‐ mm sieve but retained on a 0.062

‐ mm

sieve) in water depths representative of the lease area (1,000 to 1,400 m [3,280 to 4,593 ft])

typically range from approximately 200,000 to 550,000 individuals/m 2 (Rowe and

Kennicutt, 2009). Nematodes, nauplii, and harpacticoid copepods were the three dominant

meiofaunal groups, accounting for about 90% of total abundance.

The benthic macroinfauna is characterized by small mean individual sizes and low densities,

both of which reflect the meager primary production in Gulf of Mexico surface waters

(Wei, 2006). Densities decrease exponentially with water depth. Based on an equation

presented by Wei (2006), macroinfaunal densities in the water depths of the lease area are

expected to be about 2,400 to 3,300 individuals/m 2

, or greater than the numbers for the closest

locations listed in Table 4

.

Polychaetes are typically the most abundant macroinfaunal group on the northern Gulf of

Mexico continental slope, followed by amphipods, tanaids, bivalves, and isopods. Wei (2006)

recognized four depth

‐ dependent faunal zones (1 through 4), two of which are divided

horizontally. The lease area is in Zone 2W. This zone, with stations in water depths of

863 to 1,620 m (2,831 to 5,315 ft) had the polychaetes Tharyx marioni



### , Levinsenia uncinata

, Paraonella monilaris

, Macrochaeta clavicornis

, and Aricidea suecica as the most abundant taxa.

Megafaunal densities from nearby stations RW3 and RW4 were 195 and 762 individuals/ha,

respectively ( Table 4 ). Densities of 625 to 2,541 individuals/ha were reported from other

stations located at a depth range similar to the lease area. Common megafauna included motile

groups such as decapods, ophiuroids, holothurians, and demersal fishes, as well as sessile

groups such as sponges and anemones.

Bacteria also are an important component in terms of biomass and cycling of organic carbon

(Cruz

‐ Kaegi, 1998). Bacterial biomass at the depth range of the lease area typically is about

1 to 2 g C/m 2 in the top 15 cm of sediments (Rowe and Kennicutt, 2009).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 25 IPFs potentially affecting soft bottom benthic communities are physical disturbances to the

seafloor, effluent discharges (drilling muds and cuttings), and a large oil spill (WCD) from a well

blowout at the seafloor. A small fuel spill would not affect benthic communities because the

diesel would float and dissipate on the sea surface.



### Impacts of Physical Disturbance to the Seafloor

In water depths such as are encountered in the lease area, DP drillships or semisubmersibles

disturb the seafloor only around the wellbore (SHL) where the bottom template and blowout

preventer are located. Depending upon the specific well configuration, this area is generally

about 0.25 ha (0.62 ac).

An anchored semisubmersible would cause physical compaction of the seafloor beneath the

anchors, and chains or lines could disturb the bottom as well as resuspend sediments as they

move about. A disturbed area on the sea bottom called the “anchor sweep” forms by the swing

arc of anchor lines scraping across bottom within the range allowed by the anchoring system

configuration (BOEM, 2012). Anchored semisubmersibles disturb approximately 2 to 3 ha

(5 to 7 ac) of seafloor, depending on the number of anchors and their mooring configurations

(MMS, 2007).

The areal extent of these impacts from both DP rigs and anchored semisubmersibles will be

small compared to the lease area itself, and these type soft bottom communities are ubiquitous

along the northern Gulf of Mexico continental slope (Gallaway, 1988; Gallaway et al., 2003;

Rowe and Kennicutt, 2009). Physical disturbance of the seafloor during this project will have no

significant impact on soft bottom benthic communities in the region.



### Impacts of Effluent Discharges

Drilling muds and cuttings are the only effluents that are likely to affect benthic communities.

During initial well interval(s) before the marine riser is set, cuttings and seawater

‐ based “spud

mud” will be released at the seafloor. Excess cement slurry will also be released at the seafloor

during casing installation for the riserless portion of the drilling operations. Cement slurry

components typically include cement mix and some of the same chemicals used in water

‐ based

drilling muds (Boehm et al., 2001). The main impacts will be burial and smothering of benthic

organisms within several meters to tens of meters around the wellbore. Soft bottom sediments

disturbed by cuttings, drilling muds, and cement slurry will eventually be recolonized through

larval settlement and migration from adjacent areas. Because some deep

‐ sea biota grow and

reproduce slowly, recovery may require several years.

Discharges of washed SBM cuttings from the rig may affect benthic communities, primarily

within several hundred meters of the wellsite. The fate and effects of SBM cuttings have been

reviewed by Neff et al. (2000), and monitoring studies have been conducted in the Gulf of

Mexico by Continental Shelf Associates, Inc. (2004, 2006). In general, washed cuttings with

adhering SBMs tend to clump together and form thick cuttings piles close to the drillsite. Areas

of SBM cuttings deposition may develop elevated organic carbon concentrations and anoxic

conditions (Continental Shelf Associates, Inc., 2006). Where SBM cuttings accumulate in

concentrations of approximately 1,000 mg/kg or higher, benthic infaunal communities may be

adversely affected due to both the toxicity of the base fluid and organic enrichment

(with resulting anoxia) (Neff et al., 2000). Infaunal numbers may increase and diversity may

decrease as opportunistic species that tolerate low oxygen and high H 2 S predominateEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 26 (Continental Shelf Associates, Inc., 2006). As the base synthetic fluid is decomposed by

microbes, the area will gradually return to pre

‐ drilling conditions. Disturbed sediments will be

recolonized through larval settlement and migration from adjacent areas.

The areal extent of impacts from drilling discharges will be small. Assuming a typical effect

radius of 500 m (1,640 ft), the affected area around each wellsite would represent about 3% of

the seafloor within a lease block. Soft bottom communities are ubiquitous along the northern

Gulf of Mexico continental slope (Gallaway, 1988; Gallaway et al., 2003; Rowe and

Kennicutt, 2009). Impacts from drilling discharges during this project will have no significant

impact on soft bottom benthic communities in the region.



### Impacts of a Large Oil Spill (WCD)

The most likely effects of a subsea blowout on benthic communities would be within a few

hundred meters of the wellsite. The MMS (2007b) estimated that a severe subsurface blowout

could resuspend and disperse sediments within a 300

‐ m (984

‐ ft) radius. While coarse sediments

(sands) would probably settle at a rapid rate within 400 m (1,312 ft) from the blowout site, fine

sediments (silts and clays) could be resuspended for more than 30 days and dispersed over a

much wider area. Based on previous studies, surface sediments at the project area are assumed

to largely be silt and clay (Rowe and Kennicutt, 2009).

Recent lease sale EISs (MMS, 2007a, 2008) indicated that oil spills would be unlikely to affect

benthic communities beyond the immediate vicinity of the wellhead (i.e., due to physical

impacts of a blowout) because the oil would rise quickly to the sea surface directly over the spill

location. However, during the Macondo spill, subsurface plumes were reported at a water

depth of about 1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsite and

persisting for more than a month (Camilli et al., 2010). The subsurface plumes apparently

resulted from the use of dispersants at the wellhead (Joint Analysis Group, 2010c). While the

behavior and impacts of subsurface plumes are not well known, a subsurface plume could

contact the seafloor and affect benthic communities beyond the 300

‐ m (984

‐ ft) radius

estimated by MMS (2007a, 2008), depending on its extent, trajectory, and persistence. This

contact could result in smothering and/or toxicity to benthic organisms. The affected area

would be recolonized by benthic organisms over a period of months to years (National Research

Council, 2003).



### C.2.2 High

‐ Density Deepwater Benthic Communities

As defined by NTL 2009

‐ G40, high

‐ density deepwater benthic communities are features or areas

that could support high

‐ density chemosynthetic communities, or features or areas that could

support high

‐ density deepwater corals and other associated high

‐ density hard bottom

communities. Chemosynthetic communities were discovered in the central Gulf of Mexico in

1984 and have been studied extensively (MacDonald, 2002). Deepwater coral communities are

also known from numerous locations in the Gulf of Mexico (Brooke and Schroeder, 2007;

CSA International, Inc., 2007). These communities occur almost exclusively on authigenic

carbonates created by chemosynthetic communities.

The nearest known chemosynthetic community site is located approximately 4 miles (6 km)

north

‐ northeast of the lease area in EB 602. The nearest identified deepwater coral community

is located approximately 4 miles (6 km) north

‐ northeast of the lease area in EB 602.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 27 There are no features or areas that could support significant deepwater benthic communities

within a 2,000

‐ ft radius around the proposed wellsites. Therefore, the potential for high

‐ density

chemosynthetic communities within 2,000 ft of the proposed locations is considered low

(GEMS, 2012).

IPFs potentially affecting high

‐ density deepwater benthic communities include physical

disturbance of the seafloor, effluent discharges (drilling muds and cuttings), and a large oil spill

(WCD) from a well blowout at the seafloor. A small fuel spill would not affect benthic

communities because the diesel fuel would float and dissipate on the sea surface.



### Impacts of Physical Disturbance to the Seafloor

In water depths such as are encountered in the lease area, DP drillships or semisubmersibles

disturb the seafloor only around the wellbore (SHL) where the bottom template and blowout

preventer are located. Depending upon the specific well configuration, this area is generally

about 0.25 ha (0.62 ac). Anchored semisubmersibles disturb approximately 2 to 3 ha (5 to 7 ac)

of seafloor, depending on the number of anchors and their mooring configurations

(MMS, 2007).

The areal extent of the impacts from a DP rig will be small, and NTL 2009

‐ G40 requires that

high

‐ density deepwater benthic communities and features or areas that could support

high

‐ density chemosynthetic communities or deepwater corals communities be avoided.

Impacts from the physical disturbance of the seafloor during this project should have no impact

on chemosynthetic or deepwater coral communities in the region.



### Impacts of Effluent Discharges

The site clearance letters (GEMS, 2012) did not identify any features that could support

high

‐ density deepwater benthic communities within 610 m (2,000 ft) of the proposed drilling

locations, and the presence of chemosynthetic communities in the lease area is considered low.

Monitoring programs on the Gulf of Mexico continental slope have shown that benthic impacts

from drilling discharges typically are concentrated within about 500 m (1,640 ft) of the wellsite,

although detectable deposits may extend beyond this distance (Continental Shelf Associates,

Inc., 2004, 2006; Neff et al., 2005). Because of the water depth of the lease area, drilling

discharges would be expected to result in thinner, more diffuse accumulations on the seafloor

than those documented in the literature. Although small amounts of cuttings particles may

reach areas inhabited by high

‐ density deepwater benthic communities, the discharges are not

expected to result in significant impacts to these communities.



### Impacts of a Large Oil Spill (WCD)

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect

benthic communities beyond the immediate vicinity of the wellhead (i.e., due to physical

impacts of a blowout) because the oil would rise quickly to the sea surface directly over the spill

location. However, during the Macondo spill, subsurface plumes were reported at a water

depth of about 1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsite and

persisting for more than a month (Camilli et al., 2010). The subsurface plumes apparently

resulted from the use of dispersants at the wellhead (Joint Analysis Group, 2010c). While the

behavior and impacts of subsurface plumes are not well known, a subsurface plume could have

the potential to contact high

‐ density deepwater benthic communities beyond the 300

‐ mEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 28 (984

‐ ft) radius estimated by MMS (2007a, 2008), depending on its extent, trajectory, and

persistence. Potential impacts on sensitive resources would be an integral part of the decision

and approval process for the use of dispersants, and such approval would be obtained from the

USEPA prior to the use of dispersants.

The biological effects and expected fate of the oil remaining in the Gulf of Mexico from the

blowout are still unknown due to the depth and magnitude of this event. Hazen et al. (2010)

reported changes in plume hydrocarbon composition with distance from the source. Incubation

experiments with environmental isolates demonstrated faster than expected hydrocarbon

biodegradation rates at 5°C. Based on these results, Hazen et al. (2010) suggested the potential

exists for intrinsic bioremediation of the oil plume in the deepwater column without substantial

oxygen drawdown.

Potential impacts of oil on high

‐ density deepwater benthic communities are discussed in

MMS (2007b). Although chemosynthetic communities live among hydrocarbon seeps, natural

seepage is very constant and occurs at low rates compared to the potential rates of oil release

from a blowout. In addition, seep organisms also require unrestricted access to oxygenated

water at the same time as exposure to hydrocarbon energy sources (MacDonald, 2002). Oil

droplets or oiled sediment particles could come into contact with chemosynthetic organisms or

deepwater corals. As discussed by MMS (2007b), impacts could include loss of habitat,

biodiversity, and live coral coverage; destruction of hard substrate; change in sediment

characteristics; and reduction or loss of one or more commercial and recreational fishery

habitats. Sublethal effects could be long

‐ lasting and affect the resilience of coral colonies to

natural disturbances (e.g., elevated water temperature and diseases).

The potential for a spill to affect deepwater corals is indicated by preliminary findings from a

recent (October 2010) survey of deepwater coral habitats near the Macondo spill site

(BOEMRE, 2010). Government and academic researchers were working at a site 1,400 m

(4,600 ft) deep and approximately 7 miles (11 km) southwest of the Macondo wellhead when

they observed dead and dying corals with sloughing tissue and discoloration. Much of the soft

coral observed in an area measuring about 15 by 40 m (50 by 130 ft) was covered by what

appeared to be a brown flocculent substance (floc). Out of 40 large corals, 90% were heavily

affected and showed dead and dying parts and discoloration. Another site 400 m (1,312 ft)

farther away had a colony of stony corals similarly affected and partially covered with a similar

brown substance. Based on hopanoid petroleum biomarkers from the floc, researchers

concluded that it contained oil from the Macondo spill. The injured and dead corals were in an

area where a subsea plume of oil had been documented during the spill in June, 2010; corals

elsewhere in the GOM outside the area affected by the plume did not appear to be experiencing

higher mortality. The research team concluded that the observed coral injuries likely resulted

from exposure to the subsurface oil plume (White et al., 2012). The study location is about

378 miles (608 km) southwest of the activities discussed in this EIA.



### C.2.3 Designated Topographic Features

The block is not within or near a designated topographic feature or a no

‐ activity zone as

identified in NTL 2009

‐ G39. The nearest designated topographic feature is West Flower Garden

Bank 35 miles (57 km) north

‐ northeast of the lease area in EB 165.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 29 There are no IPFs associated with either routine operations or accidents that could cause

impacts to designated topographic features due to the distance from the lease area. A small

fuel spill would float and dissipate on the surface and would not reach these seafloor features.

In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features. If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth. Near

‐ bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf edge.



### C.2.4 Pinnacle Trend Area Live Bottoms

The lease area is not covered by the Live Bottom (Pinnacle Trend) Stipulation. As defined by

NTL 2009

‐ G39, the nearest pinnacle trend is area is in Main Pass (MP) Block 290, which lies

390 miles (628 km) east

‐ northeast of the lease area.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to pinnacle trend area live bottoms due to the distance from the lease area. A small

fuel spill would float on the surface and would not reach these seafloor features.

In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features. If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth. Near

‐ bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf edge.



### C.2.5 Live Bottom/Low Relief

The lease area is not covered by the Live Bottom (Low

‐ Relief) Stipulation, which applies to

Eastern Gulf of Mexico Planning Area leases in water depths of 100 m (328 ft) or less. The

nearest block covered by the live bottom stipulation, as defined by NTL 2009

‐ G39, is

Destin Dome (DD) Block 573, approximately 434 miles (699 km) east

‐ northeast of the lease area.

There are no IPFs associated with either routine operations or accidents that could cause

impacts to live bottom areas due to the distance from the lease area. A small fuel spill would

float and dissipate on the surface and would not reach these seafloor features.

In the event of an oil spill from a well blowout, a surface slick would not contact these seafloor

features. If a subsurface plume were to occur, impacts on these features would be unlikely due

to the distance and the difference in water depth. Near

‐ bottom currents in the region are

predicted to flow along the isobaths (Nowlin et al., 2001) and typically would not carry a plume

up onto the continental shelf.



## C.3 Threatened, Endangered, and Protected Species and Critical Habitat

This section discusses species listed as endangered or threatened under the Endangered Species

Act (ESA). In addition, it includes all marine mammal species in the region, which are protected

under the Marine Mammal Protection Act (MMPA).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 30 Endangered or threatened species that may occur in the project area and/or along the northern

Gulf Coast are listed in Table 5

. The table also indicates the location of critical habitat

(if designated in the Gulf of Mexico). Critical habitat is defined as (1) specific areas within the

geographical area occupied by the species at the time of listing, if they contain physical or

biological features essential to conservation, and those features may require special

management considerations or protection; and (2) specific areas outside the geographical area

occupied by the species if the agency determines that the area itself is essential for

conservation. The National Marine Fisheries Service (NMFS) has jurisdiction for ESA

‐ listed

cetaceans, sea turtles, and fishes in the Gulf of Mexico. The USFWS has jurisdiction for

ESA

‐ listed birds and the West Indian manatee.

Table 5. Federally listed endangered and threatened species potentially occurring in the lease

area and along the northern Gulf Coast.

Species Scientific Name Status Potential Presence Critical Habitat

Designated in

Gulf of Mexico Lease

Area Coastal

Marine Mammals

Sperm whale Physeter macrocephalus E X

‐‐ None

West Indian manatee Trichechus manatus latirostris E

‐‐ X Florida (Peninsular)

Blue whale Balaenoptera musculus E X a

‐‐ None

Fin whale Balaenoptera physalus E X a

‐‐ None

Humpback whale Megaptera novaeangliae E X a

‐‐ None

North Atlantic right whale Eubalaena glacialis E X a

‐‐ None

Sei whale Balaenoptera borealis E X a

‐‐ None

Sea Turtles

Loggerhead turtle Caretta caretta T X X None

Green turtle Chelonia mydas T, E b X X None

Leatherback turtle Dermochelys coriacea E X X None

Hawksbill turtle Eretmochelys imbricata E X X None

Kemp’s ridley turtle Lepidochelys kempi i E X X None

Birds

Piping Plover Charadrius melodus T

‐‐ X Coastal Texas, Louisiana,

Mississippi, Alabama,

and Florida (Panhandle)

Whooping Crane Grus americana E

‐‐ X Coastal Texas

(Aransas National

Wildlife Refuge)

Fishes

Gulf sturgeon Acipenser oxyrinchus desotoi T

‐‐ X Coastal Louisiana,

Mississippi, Alabama,

and Florida (Panhandle)

Smalltooth sawfish Pristis pectinata E

‐‐ X Southwest Florida and

the Florida Keys

Invertebrates

Elkhorn coral A cropora palmata T

‐‐ X Flower Garden Banks

Terrestrial Mammals

Beach mice (Alabama,

Choctawhatchee,

Perdido Key, St. Andrew) Peromyscus polionotus E

‐‐ X Alabama and Florida

(Panhandle) beaches

Abbreviations: E = endangered; T = threatened.

a The blue, fin, humpback, North Atlantic right, and sei whales are rare or extralimital in the Gulf of Mexico and are unlikely

to be present in the lease area.

b The green sea turtle is threatened, except for the Florida breeding population, which is listed as endangered.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 31 As mandated by the ESA, BOEMRE consulted NMFS and the USFWS on possible and potential

impacts from the proposed leasing in the Gulf of Mexico on endangered/threatened species and

their designated critical habitat (MMS, 2007a,b). A Biological Assessment was prepared for each

consultation. The formal ESA consultation with NMFS was concluded with receipt of the

Biological Opinion on 3 July 2007 (NMFS, 2007). The Biological Opinion concludes that the

proposed lease sales and associated activities in the Five

‐ Year Leasing Plan for Western and

Central Planning Areas 2007

‐ 2012 are not likely to jeopardize the continued existence of

threatened and endangered species under NMFS jurisdiction or destroy or adversely modify

designated critical habitat. The informal ESA consultation with USFWS was concluded with a

letter dated 14 September 2007. The USFWS concurred with MMS’s determination that

proposed actions of the current Five

‐ Year Leasing Plan were not likely to adversely affect

threatened/endangered species or designated critical habitat under USFWS jurisdiction.

Following the Macondo spill, BOEMRE requested to reinitiate an ESA consultation with both

NMFS and USFWS on 30 July 2010. The NMFS responded with a letter to BOEMRE on

24 September 2010, and the USFWS responded with a letter to BOEMRE on 27 September 2010.

At present, the NMFS and USFWS have placed the consultation process on hold because they

feel the environmental baseline information needs to be updated for the post

‐ Macondo spill

environment based on the results of the Natural Resource Damage Assessment (NRDA) process.

The NRDA data have yet to be released, and the existing consultation remains in effect

(BOEM, 2012). The existing consultation recognizes that BOEM

‐ required mitigations and other

reasonable and prudent measures should reduce the likelihood of impacts from all

BOEMRE

‐ authorized activities in the Gulf of Mexico.

Coastal endangered or threatened species that may occur along the northern Gulf Coast include

the West Indian manatee, Piping Plover, Whooping Crane, Gulf sturgeon, and four subspecies of

beach mouse. Critical habitat has been designated for all of these species as indicated in Table 5

and discussed in individual sections.

Two other coastal species (Bald Eagle and Brown Pelican) are discussed in the MMS (2007b)

lease sale EIS are no longer listed as endangered or threatened. These are discussed in

Section C.4.2

, Shorebirds and Coastal Nesting Birds

.

The sperm whale and five species of sea turtles are the only endangered or threatened species

likely to occur at or near the lease area. No critical habitat has been designated for these

species in the Gulf of Mexico.

Five endangered mysticete whales (blue whale, fin whale, humpback whale, North Atlantic right

whale, and sei whale) also have been reported from the Gulf of Mexico but are considered rare

or extralimital there (Würsig et al., 2000). No critical habitat has been designated for these

species in the Gulf of Mexico.



### C.3.1 Sperm Whale (Endangered)

The only endangered marine mammal likely to be present at or near the project area is the

sperm whale ( Physeter macrocephalus ). Resident populations of sperm whales occur within the

Gulf of Mexico; a species description is presented in a recent lease sale EIS (MMS, 2007b). Gulf

of Mexico sperm whales are classified as an endangered species and a “strategic stock” (defined

as a stock that may have unsustainable human

‐ caused impacts) by NOAA FisheriesEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 32 (Waring et al., 2009). No critical habitat for the sperm whale has been designated in the Gulf of

Mexico.

The distribution of sperm whales in the Gulf of Mexico is correlated with mesoscale physical

features such as eddies associated with the Loop Current (Jochens et al., 2008). Sperm whale

populations in the north

‐ central Gulf of Mexico are present there throughout the year

(Davis et al., 2000). Results of a multi

‐ year tracking study show female sperm whales typically

concentrated along the upper continental slope between the 200

‐ and 1,000

‐ m (656

‐ and

3,280

‐ ft) depth contours (Jochens et al., 2008). Male sperm whales were more variable in their

movements and were documented in water depths greater than 3,000 m (9,843 ft). Generally,

groups of sperm whales sighted in the Gulf of Mexico during the MMS

‐ funded Sperm Whale

Seismic Study (SWSS) consisted of mixed

‐ sex groups comprising adult females and immatures,

and groups of bachelor males. Typical group size for mixed groups was 10 individuals (Jochens

et al., 2008). SWSS results show that sperm whales transit through the vicinity of the lease area.

Movements of satellite

‐ tracked individuals suggest that this area of the Gulf continental slope is

within the home range of the Gulf of Mexico population (within the 95% utilization distribution)

(Jochens et al., 2008).

IPFs potentially affecting sperm whales include drilling rig presence, noise, and lights; support

vessel and helicopter traffic; and two types of accidents

– a small fuel spill and a large oil spill

(WCD). Effluent discharges are likely to have negligible impacts on sperm whales due to rapid

dispersion, the small area of ocean affected, the intermittent nature of the discharges, and the

mobility of these marine mammals. Compliance with NTL 2012

‐ BSEE

‐ G01 will minimize the

potential for marine debris

‐ related impacts on sperm whales.

Current threats to sperm whale populations worldwide are discussed in a final recovery plan for

the sperm whale recently published by NOAA (NMFS, 2010a). Threats are defined as “any factor

that could represent an impediment to recovery,” and include fisheries interactions,

anthropogenic noise, vessel interactions, contaminants and pollutants, disease, injury from

marine debris, research, predation and natural mortality, direct harvest, competition for

resources, loss of prey base due to climate change and ecosystem change, and cable laying.

In the Gulf of Mexico, the impacts from many of these threats are identified as either low or

unknown (BOEMRE, 2011a; BOEM, 2012).



### Impacts of Drilling Rig Presence, Noise, and Lights

Noise from routine drilling activities has the potential to disturb sperm whales. Sperm whales

appear to have good mid

‐ frequency hearing, but the available data do not indicate a consistent

response to anthropogenic noise (Southall et al., 2007). Noise intensity associated with drilling

is relatively weak, and the noise exposure of an individual animal would be transient. There are

other OCS facilities and activities near the lease area, and the region as a whole has a large

number of similar noise sources. Due to the limited scope and short duration of drilling

activities, this project would represent a small temporary contribution to the overall noise

regime.

NMFS analyzed the potential for impacts of drilling

‐ related noise on sperm whales in its

Biological Opinion for the Gulf of Mexico Oil and Gas Activities: Five

‐ Year Leasing Plan for

Western and Central Planning Areas 2007

‐ 2012 (NMFS, 2007). The analysis noted that

semisubmersible drilling rigs emit low sound source levels and concluded that drilling is notEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 33 expected to produce amplitudes sufficient to cause hearing or behavioral effects in sperm

whales; therefore, these effects are insignificant (NMFS, 2007).

Drilling rig lighting and rig presence are not identified as IPFs for sperm whales in recent lease

sale EISs (MMS, 2007b, 2008) or the NMFS (2007) Biological Opinion.



### Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb sperm whales, and there is also a risk of vessel

strikes, which are identified as a threat in the recovery plan for this species (NMFS, 2010a). Data

concerning the frequency of vessel strikes are presented in a recent lease sale EIS

(MMS, 2007b). To reduce the potential for vessel strikes, BSEE and BOEM issued

NTL 2012

‐ JOINT

‐ G01, which recommends protected species identification training and that

vessel operators and crews maintain a vigilant watch for marine mammals and slow down or

stop their vessel to avoid striking protected species, and requires operators to report sightings

of any injured or dead protected species. When whales are sighted, vessel operators and crews

are required to attempt to maintain a distance of 91 m (300 ft) or greater whenever possible.

Vessel operators are required to reduce vessel speed to 10 knots or less, when safety permits,

when mother/calf pairs, pods, or large assemblages of cetaceans are observed near an

underway vessel. Compliance with this NTL will minimize the likelihood of vessel strikes as well

as reduce the chance for disturbing sperm whales.

NMFS (2007) analyzed the potential for vessel strikes and harassment of sperm whales. With

implementation of the mitigation measures in NTL 2012

‐ JOINT

‐ G01, NMFS concluded that the

likelihood of collisions between vessels and sperm whales would be reduced to insignificant

levels. NMFS concluded that the observed avoidance of passing vessels by sperm whales is an

advantageous response to avoid a potential threat and is not expected to result in any

significant effect on migration, breathing, nursing, breeding, feeding, or sheltering to individuals,

or have any consequences at the population level. With implementation of the vessel strike

avoidance measures requirement to maintain a distance of 91 m (300 ft) from sperm whales,

the NMFS concluded that the potential for harassment of sperm whales would be reduced to

discountable levels.

Helicopter traffic also has the potential to disturb sperm whales. Smultea et al. (2008)

documented responses of sperm whales offshore Hawaii to fixed wing aircraft flying at an

altitude of 245 m (800 ft). A reaction to the initial pass of the aircraft was observed during

3 (12%) of 24 sightings. All three reactions consisted of a hasty dive and occurred at less than

360 m (1,180 ft) lateral distance from the aircraft. Additional reactions were seen when aircraft

circled certain whales to make further observations. Based on other studies of cetacean

responses to sound, the authors concluded that the observed reactions to brief overflights by

the aircraft were short

‐ term and probably of no long

‐ term biological significance.

While flying offshore in the Gulf of Mexico, helicopters maintain altitudes above 213 m (700 ft)

during transit to and from the working area. In the event that a whale is seen during transit, the

helicopter will not approach or circle the animals. Although responses are possible

(Smultea et al., 2008), the NMFS (2007) concluded that this altitude would minimize the

potential for disturbing sperm whales. Therefore, no significant impacts are expected.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 34 

### Impacts of a Small Fuel Spill

Potential spill impacts on marine mammals including sperm whales are discussed in recent lease

sale EISs (MMS, 2007b, 2008) and by NMFS (2007). Oil impacts on marine mammals are

discussed by Geraci and St. Aubin (1990). For this SEP, there are no unique site

‐ specific issues

with respect to spill impacts on these animals that were not analyzed in the previous

documents.

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer. In the unlikely event of a spill, implementation of

Anadarko’s OSRP will mitigate and lessen the potential for impacts on sperm whales. Given the

open ocean location of the lease area, the duration of a small spill and opportunity for impacts

to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products. The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours. The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft (Marine Mammal Commission [MMC], 2011). However,

due to the limited areal extent and short duration of water quality impacts from a small fuel

spill, as well as the mobility of sperm whales, no significant impacts would be expected.



### Impacts of a Large Oil Spill (WCD)

Potential spill impacts on marine mammals including sperm whales are discussed in recent EISs

(MMS, 2007b, 2008) and by NMFS (2007). For this SEP, there are no unique site

‐ specific issues

with respect to spill impacts on these animals.

Impacts of oil spills on sperm whales can include direct impacts from oil exposure, as well as

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and

dispersants) (MMC, 2011). Direct physical and physiological effects can include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey; and stress from

the activities and noise of response vessels and aircraft. Complications of the above may lead to

dysfunction of immune and reproductive systems, physiological stress, declining physical

condition, and death. Behavioral responses can include displacement of animals from prime

habitat, disruption of social structure, changing prey availability and foraging distribution and/or

patterns, changing reproductive behavior/productivity, and changing movement patterns or

migration (MMC, 2011).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 35 In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb sperm whales and potentially result in vessel strikes, entanglement, or other injury

or stress. Response vessels would operate in accordance with NTL 2012

‐ JOINT

‐ G01 to reduce

the potential for striking or disturbing these animals.



### C.3.2 West Indian Manatee (Endangered)

Most of the Gulf of Mexico manatee population is located in peninsular Florida (USFWS, 2001).

Manatee sightings in Louisiana have increased as the species extends its presence farther west

of Florida in the warmer months (Wilson, 2003). A species description is presented in a recent

lease sale EIS (MMS, 2007b) and in the recovery plan for this species (USFWS, 2001).

IPFs potentially affecting manatees include support vessel and helicopter traffic and a large oil

spill (WCD). A small fuel spill in the lease area would be unlikely to affect manatees, as the lease

area is approximately 120 miles (194 km) from the nearest shoreline (Texas). As explained in

Section A.9.2

, a small fuel spill would not be expected to make landfall or reach coastal waters

prior to breaking up. Compliance with NTL 2012

‐ BSEE

‐ G01 will minimize the potential for

marine debris

‐ related impacts on manatees.



### Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb manatees, and there is also a risk of vessel

strikes, which are identified as a threat in the recovery plan for this species (USFWS, 2001).

To reduce the potential for vessel strikes, BSEE and BOEM issued NTL 2012

‐ JOINT

‐ G01, which

recommends protected species identification training and that vessel operators and crews

maintain a vigilant watch for marine mammals and slow down or stop their vessel to avoid

striking protected species, and requires operators to report sightings of any injured or dead

protected species. Compliance with NTL 2012

‐ JOINT

‐ G01 will minimize the likelihood of vessel

strikes, and no significant impacts on manatees are expected.

Helicopter traffic also has the potential to disturb manatees. Rathbun (1988) reported that

manatees were disturbed more by helicopters than by fixed

‐ wing aircraft; however, the

helicopter was flown at relatively low altitudes of 20 to 160 m (66 to 525 ft). Helicopters used in

support operations maintain a minimum altitude of 213 m (700 ft) while in transit offshore,

305 m (1,000 ft) over unpopulated areas or across coastlines, and 610 m (2,000 ft) over

populated areas and sensitive habitats such as wildlife refuges and park properties. This

mitigation measure will minimize the potential for disturbing manatees, and no significant

impacts are expected.



### Impacts of a Large Oil Spill (WCD)

In the event that manatees were exposed to oil, effects could include direct impacts from oil

exposure, as well as indirect impacts due to response activities and materials (e.g., vessel traffic,

noise, and dispersants) (MMC, 2011). Direct physical and physiological effects can include skin

irritation, inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes;

inhalation of toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey

(or contaminated vegetation, in the case of manatees); and stress from the activities and noise

of response vessels and aircraft. Complications of the above may lead to dysfunction of immune

and reproductive systems, physiological stress, declining physical condition, and death.

Behavioral responses can include displacement of animals from prime habitat, disruption ofEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 36 social structure, changing prey availability and foraging distribution and/or patterns, changing

reproductive behavior/productivity, and changing movement patterns or migration

(MMC, 2011).

In the event that a large spill reached coastal waters where manatees were present, the level of

vessel and aircraft activity associated with spill response could disturb manatees and potentially

result in vessel strikes, entanglement, or other injury or stress. Response vessels would operate

in accordance with NTL 2012

‐ JOINT

‐ G01 to reduce the potential for striking or disturbing these

animals, and therefore no significant impacts are expected.



### C.3.3 Endangered Mysticete Whales

Five endangered mysticete whales (blue whale, fin whale, humpback whale, North Atlantic right

whale, and sei whale) also have been reported from the Gulf of Mexico but are considered rare

or extralimital there (Würsig et al., 2000). No critical habitat has been designated for these

species in the Gulf of Mexico.

Due to the rare occurrence of these whales in the Gulf of Mexico and the limited scope and

duration of the project, it is highly unlikely that any endangered mysticete would come into

contact with any project activities, either routine operations or accidents. NMFS did not include

any of these mysticete whales as affected species in its Biological Opinion (NMFS, 2007).

Potential impacts are analyzed in recent lease sale EISs (MMS, 2007b, 2008), and those analyses

are incorporated by reference. If any of these whales were present in the area, potential

impacts would be the same as those discussed below in Section C.3.4

.



### C.3.4 Non

‐ Endangered Marine Mammals (Protected)

Excluding the seven endangered species that have been cited previously, there are 22 additional

species of marine mammals that may be found in the Gulf of Mexico. This includes 2 mysticete

whales, the dwarf and pygmy sperm whales, 4 species of beaked whales, and 14 species of

delphinids. All marine mammals are protected species under the MMPA. The most common

non

‐ endangered cetaceans in the deepwater environment are odontocetes such as the

pantropical spotted dolphin, spinner dolphin, and Clymene dolphin. A brief summary is

presented below, and additional information on these groups is presented in a recent lease sale

EIS (MMS, 2007b).

Mysticete whales. Two species of non

‐ endangered mysticete whales are known from the Gulf

of Mexico. The Bryde’s whale ( Balaenoptera edeni ) has been sighted most frequently along the

100

‐ m (328

‐ ft) isobath (Davis and Fargion, 1996; Davis et al., 2000). Most sightings have been

made in the DeSoto Canyon region and off western Florida, although there have been some in

the west

‐ central portion of the northeastern Gulf. The minke whale ( Balaenoptera

acutorostrata ) is considered rare in the Gulf of Mexico, with the only confirmed records coming

from strandings (Würsig et al., 2000). Based on the available data, it is possible that Bryde’s

whales could occur in the lease area.

Dwarf and pygmy sperm whales. At sea, it is difficult to differentiate dwarf sperm whales

( Kogia sima ) from pygmy sperm whales ( Kogia breviceps ), and sightings are often grouped

together as Kogia spp. Both species have a worldwide distribution in temperate to tropical

waters. In the Gulf of Mexico, both species occur primarily along the continental shelf edge andEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 37 in deeper waters off the continental shelf (Mullin et al., 1991). Either species could occur in the

lease area.

Beaked whales. Four species of beaked whales are known from the Gulf of Mexico. They are

Blainville’s beaked whale ( Mesoplodon densirostris ), Cuvier’s beaked whale ( Ziphius cavirostris ),

Sowerby’s beaked whale ( Mesoplodon bidens ), and Gervais’ beaked whale ( Mesoplodon

europaeus ). Stranding records in the Gulf of Mexico suggest that Gervais’ beaked whale is the

most common and Sowerby’s is extralimital. Due to the difficulties of at

‐ sea identification,

beaked whales in the Gulf of Mexico are identified either as Cuvier’s beaked whales or are

grouped into an undifferentiated complex ( Mesoplodon spp. and Ziphius spp.). In the northern

Gulf of Mexico, they are broadly distributed in water depths greater than 1,000 m (3,281 ft) over

lower slope and abyssal landscapes (Davis et al., 2000). Any of these species could occur in the

lease area.

Delphinids. Fourteen species of delphinids are known from the Gulf of Mexico, including

Atlantic spotted dolphin ( Stenella frontalis ), bottlenose dolphin ( Tursiops truncatus ), Clymene

dolphin ( Stenella clymene ), false killer whale ( Pseudorca crassidens ), Fraser’s dolphin

( Lagenodelphis hosei ), killer whale ( Orcinus orca ), melon

‐ headed whale ( Peponocephala electra ),

pantropical spotted dolphin ( Stenella attenuata ), pygmy killer whale ( Feresa attenuata ),

short

‐ finned pilot whale ( Globicephala macrorhynchus ), Risso’s dolphin ( Grampus griseus ),

rough

‐ toothed dolphin ( Steno bredanensis ), spinner dolphin ( Stenella longirostris ), and striped

dolphin ( Stenella coeruleoalba ). Any of these species could occur in the lease area. The most

common non

‐ endangered cetaceans in the deepwater environment are the pantropical spotted

dolphin, spinner dolphin, and Clymene dolphin.

IPFs potentially affecting non

‐ endangered marine mammals include drilling rig presence, noise,

and lights; support vessel and helicopter traffic; and two types of accidents

‐ a small fuel spill

and a large oil spill (WCD). Effluent discharges are likely to have negligible impacts on marine

mammals due to rapid dispersion, the small area of ocean affected, the intermittent nature of

the discharges, and the mobility of marine mammals. Compliance with NTL 2012

‐ BSEE

‐ G01 will

minimize the potential for marine debris

‐ related impacts on marine mammals.



### Impacts of Drilling Rig Presence, Noise, and Lights

Noise from routine drilling activities has the potential to disturb marine mammals. Most

odontocetes (toothed whales and dolphins) use higher frequency sounds than those produced

by OCS drilling activities (Richardson et al., 1995). Noise intensity associated with drilling is

relatively weak, and the noise exposure of an individual animal would be transient. There are

other OCS facilities and activities near the lease area, and the region as a whole has a large

number of similar sources. Due to the limited scope and short duration of drilling activities, this

project would represent a small temporary contribution to the overall noise regime, and any

short

‐ term impacts are not expected to be biologically significant to marine mammal

populations.

Drilling rig lighting and rig presence are not identified as IPFs for marine mammals in recent

lease sale EISs (MMS, 2007b, 2008).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 38 

### Impacts of Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb marine mammals, and there is also a risk of

vessel strikes. Data concerning the frequency of vessel strikes are presented in a recent lease

sale EIS (MMS, 2007b). To reduce the potential for vessel strikes, BSEE and BOEM issued

NTL 2012

‐ JOINT

‐ G01, which recommends protected species identification training and that

vessel operators and crews maintain a vigilant watch for marine mammals and slow down or

stop their vessel to avoid striking protected species, and requires operators to report sightings

of any injured or dead protected species. Vessel operators and crews are required to attempt to

maintain a distance of 91 m (300 ft) or greater when whales are sighted and 45 m (150 ft) when

small cetaceans are sighted. When cetaceans are sighted while a vessel is underway, vessels

must attempt to remain parallel to the animal’s course and avoid excessive speed or abrupt

changes in direction until the cetacean has left the area. Vessel operators are required to

reduce vessel speed to 10 knots or less when mother/calf pairs, pods, or large assemblages of

cetaceans are observed near an underway vessel, when safety permits. Compliance with

NTL 2012

‐ JOINT

‐ G01 will minimize the likelihood of vessel strikes as well as reduce the chance

for disturbing marine mammals and therefore no significant impacts are expected.

Aircraft traffic also has the potential to disturb marine mammals (Würsig et al., 1998). However,

while flying offshore, helicopters maintain altitudes above 213 m (700 ft) during transit to and

from the working area. This altitude will minimize the potential for disturbing marine mammals,

and no significant impacts are expected (MMS, 2007b).



### Impacts of a Small Fuel Spill

Potential spill impacts on marine mammals are discussed in recent EISs (MMS, 2007b, 2008),

and oil impacts on marine mammals in general are discussed by Geraci and St. Aubin (1990). For

this SEP, there are no unique site

‐ specific issues with respect to spill impacts on these animals.

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during fuel

transfer. In the unlikely event of a spill, implementation of Anadarko’s OSRP is expected to

lessen the potential for impacts on marine mammals. SEP Section H provides detail on spill

response measures, along with a summary of those measures in this EIA. Given the open ocean

location of the lease area, the limited duration of a small spill and response efforts, it is

expected that any impacts would be brief and minimal.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products. The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours. The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft (MMC, 2011). However, due to the limited areal extent

and short duration of water quality impacts from a small fuel spill, as well as the mobility of

marine mammals, no significant impacts would be expected.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 39 

### Impacts of a Large Oil Spill (WCD)

Potential spill impacts on marine mammals are discussed in recent EISs (MMS, 2000, 2007b,

2008; BOEMRE, 2011a; BOEM, 2012). For this SEP, there are no unique site

‐ specific issues.

Impacts of oil spills on marine mammals can include direct impacts from oil exposure, as well as

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, and

dispersants) (MMC, 2011). Direct physical and physiological effects can include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil (and dispersants) directly or via contaminated prey (or

contaminated vegetation, in the case of manatees); and stress from the activities and noise of

response vessels and aircraft. Complications of the above may lead to dysfunction of immune

and reproductive systems, physiological stress, declining physical condition, and death.

Behavioral responses can include displacement of animals from prime habitat, disruption of

social structure, changing prey availability and foraging distribution and/or patterns, changing

reproductive behavior/productivity, and changing movement patterns or migration

(MMC, 2010).

In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb marine mammals and potentially result in vessel strikes, entanglement, or other

injury or stress. Response vessels would operate in accordance with NTL 2012

‐ JOINT

‐ G01 to

reduce the potential for striking or disturbing these animals, and therefore no significant

impacts are expected.



### C.3.5 Sea Turtles (Endangered/Threatened)

Five species of endangered or threatened sea turtles may be found near the lease area.

Leatherback ( Dermochelys coriacea ), Kemp's ridley ( Lepidochelys kempii ), and hawksbill

( Eretmochelys imbricata ) turtles are endangered. The loggerhead turtle ( Caretta caretta ) is a

threatened species; however, in March 2010, NMFS and USFWS proposed to list the Northwest

Atlantic Ocean population of loggerhead turtles as endangered (75 FR 12598). The green turtle

( Chelonia mydas ) is listed as threatened, except for the Florida and Pacific Coast of Mexico

breeding populations, which are listed as endangered. Species descriptions are presented in

MMS (2007b).

The extent and scope of the Macondo spill represents new information not assessed in the

existing ESA Section 7 consultation under the current Five

‐ Year Program. As a result of this new

information, BOEMRE reinitiated ESA Section 7 consultation on the existing Gulf of Mexico lease

sale EIS with NMFS and the USFWS on 30 July 2010. The NMFS responded with a letter to

BOEMRE on 24 September 2010, and the USFWS responded with a letter to BOEMRE on

27 September 2010. However, NMFS and the USFWS have placed the consultation process on

hold pending the results of the NRDA post

‐ Macondo spill data review, which has yet to be

released. The existing consultation currently remains in effect (BOEM, 2012).

BOEMRE (2011a) and BOEM (2012) reexamined the impacts analyses presented in MMS (2007b,

2008) for the five sea turtle species that inhabit the Gulf of Mexico based on additional

information and in consideration of the Macondo spill. No new information was found that

would alter the potential impacts on sea turtles described in previous EISs. In most foreseeable

cases, exposure to hydrocarbons persisting in the sea following the dispersal of an oil slick will

result in sublethal impacts (e.g., decreased health, reproductive fitness, and longevity; and

increased vulnerability to disease) to sea turtles.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 40 Leatherbacks and loggerheads are the most likely species to be present near the lease area as

adults. Green, hawksbill, and Kemp’s ridley turtles are typically inner shelf and nearshore

species, unlikely to occur near the lease area as adults. Hatchlings or juveniles of any of the sea

turtle species may be present in deepwater areas, including the lease area, where they may be

associated with Sargassum and other flotsam.

Sea turtle nesting in the northern Gulf of Mexico can be summarized by species as follows:

 Loggerhead turtles

– Loggerheads nest in significant numbers along the Florida Panhandle

and, to a lesser extent, from Texas through Alabama (MMS, 2007b). The nearest significant

nesting area of loggerhead turtles is found in Louisiana, on beaches within the Breton NWR;

 Green and leatherback turtles

– Green and leatherback turtles infrequently nest on Florida

Panhandle beaches (Florida Fish and Wildlife Conservation Commission, 2011);

 Kemp’s ridley turtles

– The main Kemp’s ridley nesting site is Rancho Nuevo beach,

Tamaulipas, Mexico (NMFS et al., 2011). Kemp’s ridley turtles typically do not nest

anywhere near the project area, although there have been occasional reports of Kemp’s

ridleys nesting in Alabama (Share the Beach, 2010); and

 Hawksbill turtles

– Hawksbills typically do not nest anywhere near the project area.

IPFs potentially affecting sea turtles include drilling rig presence, noise, and lights; support

vessel and helicopter traffic; and two types of accidents

‐ a small fuel spill and a large oil spill

(WCD). Effluent discharges are likely to have negligible impacts on sea turtles due to rapid

dispersion, the small area of ocean affected, and the intermittent nature of the discharges.

Compliance with NTL 2012

‐ BSEE

‐ G01 will minimize the potential for marine debris

‐ related

impacts on sea turtles.



### Impacts of Drilling Rig Presence, Noise, and Lights

Offshore drilling activities produce a broad array of sounds at frequencies and intensities that

may be detected by sea turtles (Geraci and St. Aubin, 1987). Potential impacts may include

behavioral disruption and temporary or permanent displacement from the area near the sound

source. Certain sea turtles, especially loggerheads, may be attracted to offshore structures

(Lohoefener et al., 1990) and, thus, may be more susceptible to impacts from sounds produced

during routine operations. Helicopters and service vessels may also affect sea turtles due to

machinery noise and/or visual disturbances. The most likely impacts would be short

‐ term

behavioral changes such as diving and evasive swimming, disruption of activities, or departure

from the area. Due to the limited scope and short duration of drilling activities, these

short

‐ term impacts are not expected to be biologically significant to sea turtle populations.

Artificial lighting can disrupt the nocturnal orientation of sea turtle hatchlings

(Witherington, 1997; Tuxbury and Salmon, 2005). However, hatchlings may rely less on light

cues when they are offshore than when they are emerging on the beach (Salmon and

Wyneken, 1990). The NMFS (2007) concluded that the effects of lighting from offshore

structures on sea turtles are insignificant.



### Support Vessel and Helicopter Traffic

Support vessel traffic has the potential to disturb sea turtles, and there is also a risk of vessel

strikes. Data show that vessel traffic is one cause of sea turtle mortality in the Gulf of Mexico

(Lutcavage et al., 1997). While adult sea turtles are visible at the surface during the day and in

clear weather, they can be difficult to spot from a moving vessel when resting below the waterEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 41 surface, during nighttime, or during periods of inclement weather. To reduce the potential for

vessel strikes, BSEE and BOEM issued NTL 2012

‐ JOINT

‐ G01, which recommends protected

species identification training and that vessel operators and crews maintain a vigilant watch for

sea turtles and slow down or stop their vessel to avoid striking protected species, and requires

operators to report sightings of any injured or dead protected species. When sea turtles are

sighted, vessel operators and crews are required to attempt to maintain a distance of 45 m

(150 ft) or greater whenever possible. Compliance with this NTL will minimize the likelihood of

vessel strikes as well as reduce the chance for disturbing sea turtles (NMFS, 2007).

Helicopter traffic also has the potential to disturb sea turtles. However, while flying offshore,

helicopters maintain altitudes above 213 m (700 ft) during transit to and from the working area.

This altitude will minimize the potential for disturbing sea turtles, and no significant impacts are

expected.



### Impacts of a Small Fuel Spill

Potential spill impacts on sea turtles are discussed in recent EISs (MMS, 2007b, 2008) and the

NMFS Biological Opinion (NMFS, 2007). For this SEP, there are no unique site

‐ specific issues

with respect to spill impacts on these animals.

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during fuel

transfer. In the unlikely event of a spill, implementation of Anadarko’s OSRP is expected to

minimize potential impacts on sea turtles. SEP Section H provides detail on spill response

measures. Given the open ocean location of the lease area, the duration of a small spill and

opportunity for impacts to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products. The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours. The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Direct physical and physiological effects of exposure to diesel fuel could include skin irritation,

inflammation, or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of

toxic fumes; ingestion of oil directly or via contaminated prey; and stress from the activities and

noise of response vessels and aircraft. However, due to the limited areal extent and short

duration of water quality impacts from a small fuel spill, no significant impacts would be

expected.

A small fuel spill in the lease area would be unlikely to affect sea turtle nesting beaches, as the

lease area is 120 miles (194 km) from the nearest shoreline (Texas). As explained in

Section A.9.2

, a small fuel spill would not be expected to make landfall or reach coastal waters

prior to breaking up.



### Impacts of a Large Oil Spill (WCD)

Impacts of oil spills on sea turtles can include direct impacts from oil exposure, as well as

indirect impacts due to response activities and materials (e.g., vessel traffic, noise, andEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 42 dispersants). Direct physical and physiological effects can include skin irritation, inflammation,

or necrosis; chemical burns of skin, eyes, and mucous membranes; inhalation of toxic fumes and

smoke (e.g., from in situ burning of oil); ingestion of oil (and dispersants) directly or via

contaminated food; and stress from the activities and noise of response vessels and aircraft.

Complications of the above may lead to dysfunction of immune and reproductive systems,

physiological stress, declining physical condition, and death. Behavioral responses can include

displacement of animals from prime habitat, disruption of social structure, changing food

availability and foraging distribution and/or patterns, changing reproductive

behavior/productivity, and changing movement patterns or migration. In the unlikely event of a

spill, implementation of Anadarko’s OSRP is expected to minimize the potential for these types

of impacts on sea turtles. SEP Section H provides detail on spill response measures.

Studies of oil effects on loggerheads in a controlled setting (Lutcavage et al., 1995) suggest that

sea turtles show no avoidance behavior when they encounter an oil slick, and any sea turtle in

an affected area would be expected to be exposed. Sea turtles’ diving behaviors also put them

at risk. Sea turtles rapidly inhale a large volume of air before diving and continually resurface

over time, which may result in repeated exposure to volatile vapors and oiling (NMFS, 2007).

Spilled oil reaching sea turtle nesting beaches could have effects on nesting sea turtles and egg

development (NMFS, 2007). An oiled beach could affect nest site selection or result in no

nesting at all (e.g., false crawls). Upon hatching and successfully reaching the water, hatchlings

are subject to the same types of oil spill exposure hazards as adults. Hatchlings that contact oil

residues while crossing a beach can exhibit a range of effects, from acute toxicity to impaired

movement and normal bodily functions (NMFS, 2007).

In the event of a large spill, the level of vessel and aircraft activity associated with spill response

could disturb sea turtles and potentially result in vessel strikes, entanglement, or other injury or

stress. Response vessels would operate in accordance with NTL 2012

‐ JOINT

‐ G01 to reduce the

potential for striking or disturbing these animals, and therefore no significant impacts are

expected.



### C.3.6 Piping Plover (Threatened)

The Piping Plover ( Charadrius melodus ) is a migratory shorebird that overwinters along the

southeastern U.S. and Gulf of Mexico coasts. This threatened species is in decline as a result of

hunting, habitat loss and modification, predation, and disease (USFWS, 2003). Critical

overwintering habitat has been designated, including beaches in Texas, Louisiana, Mississippi,

Alabama, and Florida ( Figure 3 ). Piping Plovers inhabit coastal sandy beaches and mudflats,

feeding by probing for invertebrates at or just below the surface. They use beaches adjacent to

foraging areas for roosting and preening (USFWS, 2010a). A species description is presented in a

recent lease sale EIS (MMS, 2007b).

A large oil spill (WCD) is the only IPF potentially affecting Piping Plovers. There are no IPFs

associated with routine project activities that could affect these birds. A small fuel spill in the

lease area would be unlikely to affect Piping Plovers because a small fuel spill would not be

expected to make landfall or reach coastal waters prior to breaking up (see explanation in

Section A.9.2 ).EastBreaksBlocks645,689,and690May2012EnvironmentalImpactAnalysisforSupplementalExplorationPlanPage43Figure3.Locationofselectedenvironmentalfeaturesinrelationtotheleasearea.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 44 

### Impacts of a Large Oil Spill (WCD)

The lease area is 120 miles (194 km) from the nearest shorelines inhabited by Piping Plovers

( Figure 3 ). The revised OSRA results (BOEMRE, 2011a; BOEM, 2012) summarized in

Section A.9.3 ( Table 3 ) predict that during the spring there is a 18% probability that an oil spill

from the lease area would reach a shoreline designated as critical habitat for the Piping Plover

within 10 days. Plovers could physically oil themselves while foraging on oiled shores or

secondarily contaminate themselves through ingestion of oiled intertidal sediments and prey

(MMS, 2007b). Plovers congregate and feed along tidally exposed banks and shorelines,

following the tide out and foraging at the water’s edge. It is possible that some deaths of Piping

Plovers could occur, especially if spills occur during winter months when plovers are most

common along the coastal Gulf or if spills contacted critical habitat. Impacts could also occur

from vehicular traffic on beaches and other activities associated with spill cleanup. Anadarko

has extensive resources available to protect and rehabilitate wildlife in the event of a spill

reaching the shoreline, as detailed in the OSRP.



### C.3.7 Whooping Crane (Endangered)

The Whooping Crane ( Grus americana ) is an omnivorous wading bird and an endangered

species. There are three wild populations in North America (Whooping Crane Eastern

Partnership, 2010). One population winters along the Texas coast at Aransas NWR and

summers at Wood Buffalo National Park in Canada; this population represents the majority of

the world’s population of free

‐ ranging Whooping Cranes and reached a record population of

270 at Aransas NWR in December 2008 (Whooping Crane Eastern Partnership, 2010).

A nonmigrating population has been reintroduced in central Florida, and another reintroduced

population summers in Wisconsin and migrates to the southeastern U.S. for the winter.

Whooping Cranes breed, migrate, winter, and forage in a variety of habitats, including coastal

marshes and estuaries, inland marshes, lakes, ponds, wet meadows and rivers, and agricultural

fields (USFWS, 2007). About 9,000 ha (22,240 ac) of salt flats on Aransas NWR and adjacent

islands comprise the principal wintering grounds of the Whooping Crane. Aransas NWR is

designated as critical habitat for the species. A species description is presented in a recent lease

sale EIS (MMS, 2007b).

A large oil spill (WCD) is the only IPF potentially affecting Whooping Cranes. A small fuel spill in

the lease area would also be unlikely to affect Whooping Cranes, due to the distance from

Aransas NWR. As explained in Section A.9.2

, a small fuel spill would not be expected to make

landfall or reach coastal waters prior to breaking up.



### Impacts of a Large Oil Spill (WCD)

A large oil spill is unlikely to affect Whooping Cranes as the lease area is approximately

137 miles (221 km) from its critical habitat designated in the Aransas NWR. The revised

OSRA modeling (BOEM, 2012) predicts that there is an 11% or less probability that an oil spill

originating in the lease area would reach the Aransas NWR within 30 days and a 20% probability

of oil reaching that area in 120 days.

In the event of oil exposure, Whooping Cranes could physically oil themselves while foraging in

oiled areas or secondarily contaminate themselves through ingestion of contaminated shellfish,

frogs, and fishes. It is possible that some Whooping Crane deaths could occur. In the event of a

spill, Anadarko would work with the applicable State and Federal agencies to prevent impacts

from a spill.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 45 

### C.3.8 Gulf Sturgeon (Threatened)

The Gulf sturgeon ( Acipenser oxyrinchus desotoi ) is a threatened fish species that inhabits major

rivers and inner shelf waters from the Mississippi River to the Suwannee River, Florida

(Barkuloo, 1988; Wakeford, 2001). An anadromous fish that migrates from the sea upstream

into coastal rivers to spawn in freshwater, it historically ranged from the Mississippi River to

Charlotte Harbor, Florida (Wakeford, 2001). Today, this range has contracted to encompass

major rivers and inner shelf waters from the Mississippi River to the Suwannee River, Florida.

Populations have been depleted or even extirpated throughout this range by fishing, shoreline

development, dam construction, water quality changes, and other factors (Barkuloo, 1988;

Wakeford, 2001). These declines prompted the listing of the Gulf sturgeon as a threatened

species in 1991. The best known populations occur in the Apalachicola and Suwannee Rivers in

Florida (Carr, 1996; Sulak and Clugston, 1998), the Choctawhatchee River in Alabama

(Fox et al., 2000), and the Pearl River in Mississippi/Louisiana (Morrow et al., 1998). Critical

habitat in the Gulf extends from Lake Borgne, Louisiana (St. Bernard Parish) to Suwannee Sound,

Florida (Levy County) (NMFS, 2010b) ( Figure 3 ). A species description is presented in a recent

lease sale EIS (MMS, 2007b) and in the recovery plan for this species (USFWS and Gulf States

Marine Fisheries Commission, 1995).

A large oil spill (WCD) is the only IPF potentially affecting Gulf sturgeon. There are no IPFs

associated with routine project activities that could affect these fish. A small fuel spill in the

lease area would be unlikely to affect Gulf sturgeon because a small fuel spill would not be

expected to make landfall or reach coastal waters prior to breaking up (see explanation in

Section A.9.2 ).



### Impacts of a Large Oil Spill (WCD)

Potential spill impacts on Gulf sturgeon are discussed in recent EISs (MMS, 2007b, 2008;

BOEMRE, 2011a; BOEM, 2012) and by NMFS (2007). For this SEP, there are no unique

site

‐ specific issues with respect to this species.

The lease area is approximately 322 miles (518 km) from the nearest Gulf sturgeon critical

habitat. The revised OSRA modeling (BOEM, 2012) predicts that a spill in the lease area has

1% or less probability of contacting any coastal areas inhabited by Gulf sturgeon within

30 or 120 days.

In the event of oil reaching Gulf sturgeon habitat, the fish could be affected by direct ingestion,

ingestion of oiled prey, or the absorption of dissolved petroleum products through the gills.

Based on the life history of this species, subadult and adult Gulf sturgeon would be most

vulnerable to an estuarine or marine oil spill, and would be vulnerable only from

1 September through 30 April when this species is foraging in estuarine and shallow marine

habitats (NMFS, 2007).



### C.3.9 Smalltooth Sawfish (Endangered)

Smalltooth sawfish ( Pristis pectinata ) are found in the tropical and subtropical Atlantic Ocean.

In the Western Atlantic they have historically ranged from New York to Brazil, including the Gulf

of Mexico and Caribbean Sea. This sawfish primarily occurs in estuarine and coastal habitats

such as bays, lagoons, and rivers. The smalltooth sawfish was listed as endangered under the

ESA on 1 April 2003. Its critical habitat consists of two units: the Charlotte Harbor Estuary Unit,

which comprises approximately 89,621 ha (221,459 ac) of coastal habitat, and the Ten ThousandEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 46 Islands/Everglades Unit, which comprises approximately 250,506 ha (619,013 ac) of coastal

habitat. The two units are located along the southwestern coast of Florida between

Charlotte Harbor and Florida Bay.

A large oil spill (WCD) is the only IPF potentially affecting smalltooth sawfish. There are no IPFs

associated with routine project activities that could affect these fish. A small fuel spill in the

lease area would be unlikely to affect smalltooth sawfish because a small fuel spill would not be

expected to make landfall or reach coastal waters prior to breaking up (see Section A.9.2 ).



### Impacts of a Large Oil Spill (WCD)

Potential spill impacts on smalltooth sawfish are similar to those discussed for other coastal and

estuarine species in recent lease sale EISs (MMS, 2007b, 2008) and by the NMFS (2007) in its

Biological Opinion. For this SEP, there are no unique site

‐ specific issues with respect to

smalltooth sawfish.

In the event of oil reaching smalltooth sawfish habitat, the fish could be affected by direct

ingestion, ingestion of oiled prey, or the absorption of dissolved petroleum products through

the gills.



### C.3.10 Beach Mice (Endangered)

Four subspecies of endangered beach mouse ( Peromyscus polionotus ) occur on the barrier

islands of Alabama and the Florida Panhandle: the Alabama, Choctawhatchee, Perdido Key, and

St. Andrew beach mice. Critical habitat has been designated for all four subspecies; Figure 3

shows the critical habitat combined for all four subspecies. Species descriptions are provided in

a recent lease sale EIS (MMS, 2007b).

A large oil spill (WCD) is the only IPF potentially affecting beach mice. There are no IPFs

associated with routine project activities that could affect these animals due to the distance

from shore and the lack of any onshore support activities near their habitat. A small fuel spill in

the lease area would not affect beach mice because a small fuel spill would not be expected to

make landfall or reach coastal waters prior to breaking up (see Section A.9.2 ).



### Impacts of a Large Oil Spill (WCD)

Potential spill impacts on beach mice are discussed in recent lease sale EISs (MMS, 2007b,

2008). For this SEP, there are no unique site

‐ specific issues with respect to these species that

were not analyzed in these documents.

The lease area is about 440 miles (708 km) west

‐ southwest from the nearest beach mouse

critical habitat. The revised OSRA modeling summarized in Section A.9.3 predicts that a spill in

the lease area has a 0.5% or less probability of reaching either the Alabama or Florida shorelines

inhabited by beach mice within 120 days.

In the event of oil contacting these beaches, beach mice could experience several types of direct

and indirect impacts. Contact with spilled oil could cause skin and eye irritation and subsequent

infection; matting of fur; irritation of sweat glands, ear tissues, and throat tissues; disruption of

sight and hearing; asphyxiation from inhalation of fumes; and toxicity from ingestion of oil and

contaminated food. Indirect impacts could include reduction of food supply, destruction of

habitat, and fouling of nests. Impacts could also occur from vehicular traffic and other activitiesEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 47 associated with spill cleanup. However, any such impacts are unlikely due to the distance from

shore and response actions that would occur in the event of a spill.



### C.3.11 Elkhorn Coral (Threatened)

Elkhorn coral ( Acropora palmata ) is found primarily in shallow waters with temperatures ranging

between 26°C and 30°C (79°F and 86°F) and significant water movement. Elkhorn coral was

once one of the most abundant coral species in waters ranging from 1 to 5 m (3.3 to 16 ft) deep

in tropical and subtropical waters. In the northern Gulf, elkhorn coral has been found within the

coral cap region of the Flower Garden Banks National Marine Sanctuary (Flower Garden Banks

National Marine Sanctuary, 2011).

There are no IPFs associated with routine project activities that could affect this species in the

northern Gulf. A small fuel spill would not affect elkhorn coral colonies because the oil would

float and dissipate on the sea surface. A WCD would be unlikely to affect the coral cap region of

the Flower Garden Banks because of the water depth of the area. Although subsurface plumes

were reported following the Macondo spill, these plumes resulted from the use of subsea

dispersants at the seafloor.



## C.4 Coastal and Marine Birds

C.4.1 Marine Birds

Marine birds include seabirds and other species that may occur in the pelagic environment of

the project area (Clapp et al., 1982a,b, 1983; Peake, 1996; Hess and Ribic, 2000). Seabirds spend

much of their lives offshore over the open ocean, except during breeding season when they nest

along the coast. In addition, other birds such as waterfowl, marsh birds, and shorebirds may

occasionally be present over open ocean areas. No endangered or threatened bird species are

likely to occur at the project area due to the distance from shore. For a discussion of shorebirds

and coastal nesting birds, see Section C.4.2

.

Seabirds of the northern Gulf of Mexico were surveyed from ships during the GulfCet II program.

Hess and Ribic (2000) reported that terns, storm

‐ petrels, shearwaters, and jaegers were the

most frequently sighted seabirds in the deepwater area. From these surveys, four ecological

categories of seabirds were documented in the deepwater areas of the Gulf: summer migrants

(shearwaters, storm petrels, boobies); summer residents that breed in the Gulf (Sooty Tern,

Least Tern, Sandwich Tern, Magnificent Frigatebird); winter residents (gannets, gulls, jaegers);

and permanent resident species (Laughing Gulls, Royal Terns, Bridled Terns) (Hess and

Ribic, 2000).

Common seabird species include Wilson’s Storm

‐ Petrel ( Oceanites oceanicus ), Magnificent

Frigatebird ( Fregata magnificens ), Northern Gannet ( Morus bassanus ), Masked Booby

( Sula dactylatra ), Brown Booby ( Sula leucogaster ), Cory’s Shearwater ( Calonectris diomedea ),

Greater Shearwater ( Puffinus gravis ), and Audubon’s Shearwater ( Puffinus lherminieri ). Seabirds

are distributed Gulf

‐ wide and are not specifically associated with the lease area.

Relationships with hydrographic features were found for several seabird species, possibly due to

effects of hydrography on nutrient levels and productivity of surface waters where birds forage.

The GulfCet II study did not estimate bird densities; however, Powers (1987) indicates that

seabird densities over the open ocean typically are <10 birds/km 2

.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 48 Trans

‐ Gulf migrant birds including shorebirds, wading birds, and terrestrial birds may also be

present in the lease area. Migrant birds may use offshore structures and rigs for resting,

feeding, or as temporary shelter from inclement weather (Russell, 2005). Some birds may be

attracted to offshore structures because of the lights and the fish populations that aggregate

around these structures.

IPFs potentially affecting marine and pelagic birds include drilling rig presence, noise, and lights;

support vessel and helicopter traffic; and two types of accidents

‐ a small fuel spill and a large oil

spill (WCD). Effluent discharges are likely to have negligible impacts on the birds due to rapid

dispersion, the small area of ocean affected, the intermittent nature of the discharges, and the

mobility of these animals. Compliance with NTL 2012

‐ BSEE

‐ G01 will minimize the potential for

marine debris

‐ related impacts on birds.



### Impacts of Drilling Rig Presence, Noise, and Lights

Birds that frequent rigs may be exposed to contaminants including air pollutants and routine

discharges, but significant impacts are unlikely due to rapid dispersion. Birds migrating over

water have been known to strike offshore structures, resulting in death or injury (Wiese et al.,

2001; Russell, 2005). Mortality of migrant birds at tall towers and other land

‐ based structures

has been reviewed extensively, and the mechanisms involved in rig collisions appear to be

similar. In some cases, migrants simply do not see a part of the rig until it is too late. In other

cases, navigation may be disrupted by noise (Russell, 2005). On the other hand, offshore

structures are suitable stopover habitats for most trans

‐ Gulf migrant species, and most of the

migrants that stop over on rigs probably benefit from their stay, particularly in spring

(Russell, 2005). Due to the limited scope and short duration of drilling activities described in this

EP, any impacts on populations of either seabirds or trans

‐ Gulf migrant birds are not expected

to be significant.

A recent study in the North Sea indicated that rig lighting causes circling behavior in various

birds, especially on cloudy nights; apparently the birds’ geomagnetic compass is upset by the

red part of the spectrum from the lights currently in use (Nederlandse Aardolie Maatschappij,

2007). The numbers varied greatly, from none at all to some tens of thousands of birds per

night per rig, with an apparent effect radius of up to 3 miles (5 km). A study in the Gulf of

Mexico also noted the phenomenon but did not recommend mitigation (Russell, 2005). In

laboratory experiments, Poot et al. (2008) found the magnetic compass of migratory birds to be

wavelength dependent. Migratory birds require light from the blue

‐ green part of the spectrum

for magnetic compass orientation, whereas red light (visible long

‐ wavelength) disrupts their

magnetic orientation. They designed a field study to test if and how changing light color

influenced migrating birds under field conditions. During field studies they found that

nocturnally migrating birds were disoriented and attracted by red and white light (containing

visible long

‐ wavelength radiation), whereas they were clearly less disoriented by blue and green

light (containing less or no visible long

‐ wavelength radiation) (Poot et al., 2008). Factors to

consider in evaluating this impact in the Gulf of Mexico would include the lower incidence of

cloudy and foggy days in the Gulf of Mexico versus the North Sea. Due to the limited scope and

short duration of drilling activities proposed in this SEP, lighting impacts, collisions, or other

adverse effects are unlikely, and no significant impacts are expected.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 49 

### Impacts of Support Vessel and Helicopter Traffic

Support vessels and helicopters are unlikely to significantly disturb pelagic birds in open,

offshore waters. It is likely that individual birds would experience, at most, only short

‐ term

behavioral disruption, and the impact would not be significant.



### Impacts of a Small Fuel Spill

Potential spill impacts on marine birds are discussed in recent EISs (MMS, 2007b, 2008). For this

SEP, there are no unique site

‐ specific issues with respect to spill impacts on these animals.

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer. In the unlikely event of a spill, implementation of

Anadarko’s OSRP will reduce the potential for impacts on marine and pelagic birds.

EP Section H provides detail on spill response measures. Given the open ocean location of the

lease area, the duration of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products. The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours. The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

Birds exposed to oil on the sea surface could experience direct physical and physiological effects

including skin irritation; chemical burns of skin, eyes, and mucous membranes; and inhalation of

toxic fumes. Due to the limited areal extent and short duration of water quality impacts from a

small fuel spill, secondary impacts due to ingestion of oil via contaminated prey or reductions in

prey abundance are unlikely. Due to the low densities of birds in open ocean areas, the small

area affected, and the brief duration of the surface slick, no significant impacts on pelagic birds

would be expected.



### Impacts of a Large Oil Spill (WCD)

Potential spill impacts on marine and pelagic birds are discussed in recent EISs (MMS, 2007b,

2008). For this SEP, there are no unique site

‐ specific issues with respect to spill impacts on

these animals.

BOEM has reexamined the analyses for coastal and marine birds presented in MMS (2007b,

2008) and determined that no new information was found that would alter the potential

impacts on marine and pelagic birds (BOEMRE, 2011a; BOEM, 2012).

Pelagic seabirds could be exposed to oil from a spill at the project area. Hess and Ribic (2000)

reported that terns, storm

‐ petrels, shearwaters, and jaegers were the most frequently sighted

seabirds in the deepwater Gulf of Mexico (>200 m). Powers (1987) indicates that seabird

densities over the open ocean typically are <10 birds/km 2

. The number of pelagic birds that

could be affected in open, offshore waters would depend on the extent and persistence of the

oil slick.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 50 The recent Macondo spill provides relevant information about the species of pelagic birds that

may be affected in the event of a large oil spill. Birds that have been treated for oiling include

several pelagic species such as the Northern Gannet, Magnificent Frigatebird, and Masked

Booby (USFWS, 2011). The Northern Gannet is among the species with the largest numbers of

birds affected by the spill.



### C.4.2 Shorebirds and Coastal Nesting Birds

Threatened and endangered bird species (Piping Plover and Whooping Crane) have been

discussed previously in Section C.3

. Various species of non

‐ endangered birds are also found

along the northern Gulf Coast, including diving birds, shorebirds, marsh birds, wading birds, and

waterfowl. Gulf Coast marshes and beaches also provide important feeding grounds and

nesting habitats. Species that breed on beaches, flats, dunes, bars, barrier islands, and similar

habitats include the Sandwich Tern, Wilson’s Plover, Black Skimmer, Forster’s Tern, Gull

‐ billed

Tern, Laughing Gull, Least Tern, and Royal Tern (USFWS, 2010b). Additional information is

presented in recent lease sale EISs (MMS, 2007b, 2008).

The Brown Pelican ( Pelecanus occidentalis ) was delisted from Federal endangered status in 2009

(USFWS, 2010c). However, this species is listed as a species of greatest conservation need by

the State of Mississippi (Mississippi Department of Wildlife, Fisheries and Parks, 2011) and as a

species of special concern by the State of Florida (Florida Fish and Wildlife Conservation

Commission, 2011). Brown Pelicans inhabit coastal habitats and forage within both coastal

waters and waters of the inner continental shelf. Aerial and shipboard surveys, including

GulfCet and GulfCet II, indicate that Brown Pelicans do not occur in deep offshore waters

(Fritts and Reynolds, 1981; Peake, 1996; Hess and Ribic, 2000). Nearly half the southeastern

population of Brown Pelicans lives in the northern Gulf Coast, generally nesting on protected

islands (USFWS, 2010b).

The Southern Bald Eagle ( Haliaeetus leucocephalus ) was delisted from its threatened status in

the lower 48 states on 28 June 2007. The Bald Eagle is a terrestrial raptor widely distributed

across the southern U.S., including coastal habitats along the Gulf of Mexico. The Gulf Coast is

inhabited by both wintering migrant and resident Bald Eagles (Johnsgard, 1990; Ehrlich et al.,

1992).

IPFs potentially affecting shorebirds and coastal nesting birds include support vessel and

helicopter traffic and a large oil spill (WCD). A small fuel spill in the lease area would be unlikely

to affect shorebirds or coastal nesting birds, as the lease area is 120 miles (194 km) from the

nearest shoreline (Texas). As explained in Section A.9.2

, a small fuel spill would not be expected

to make landfall or reach coastal waters prior to breaking up. Compliance with

NTL 2012

‐ BSEE

‐ G01 will minimize the potential for marine debris

‐ related impacts on shorebirds.



### Impacts of Support Vessel and Helicopter Traffic

Support vessels and helicopters will transit coastal areas near Port Fourchon and Houma,

Louisiana, where shorebirds and coastal nesting birds may be found. These activities could

periodically disturb individuals or groups of birds within sensitive coastal habitats (e.g., wetlands

that may support feeding, resting, or breeding birds).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 51 Vessel traffic may disturb some foraging and resting birds. Flushing distances vary between

species and between individuals (Rodgers and Schwikert, 2002). The disturbances will be

limited to flushing birds away from vessel pathways; known distances are from 20 to 49 m

(65 to 160 ft) for personal watercraft and 23 to 58 m (75 to 190 ft) for an outboard

‐ powered

boat (Rodgers and Schwikert, 2002). Flushing distances may be similar or less for the support

vessels to be used for Anadarko’s project, and some species such as gulls are attracted to boats.

Support vessels will not approach nesting or breeding areas on the shoreline, so disturbances to

nesting birds, eggs, and chicks is not expected. Vessel operators will use designated navigation

channels and comply with posted speed and wake restrictions while transiting sensitive inland

waterways. Due to the limited scope and short duration of drilling activities, any short

‐ term

impacts are not expected to be biologically significant to coastal bird populations.

Aircraft traffic can cause some disturbance to birds onshore and offshore. Responses are highly

dependent on the type of aircraft, the bird species, the activities that animals were previously

engaged in, and previous exposures to overflights (Efroymson et al., 2000). Helicopters seem to

cause the most intense responses over other human disturbances for some species

(Bélanger and Bédard, 1989). However, Federal Aviation Administration Advisory Circular

No. 91

‐ 36D recommends that pilots maintain a minimum altitude of 610 m (2,000 ft) when

flying over noise

‐ sensitive areas such as wildlife refuges, parks, and areas with wilderness

characteristics. This is greater than the distance (slant range) at which aircraft overflights have

been reported to cause behavioral effects on most species of birds studied (Efroymson et al.,

2000). With these guidelines in effect, it is likely that individual birds would experience, at most,

only short

‐ term behavioral disruption.



### Impacts of Large Oil Spill (WCD)

Data from the Macondo spill provide additional information about the species of coastal and

shore birds that may be affected in the event of a catastrophic spill of a similar nature and

duration. This information supplements the analysis presented in the lease sale EIS

(MMS, 2007b). According to USFWS (2010d) and based on the latest reports, about 5,000 dead

birds have been collected since the spill began, and about 1,900 of the dead animals were visibly

oiled. In addition, over 2,000 oiled birds have been collected alive and about 1,200 released

(NMFS, 2010c). According to the USFWS (2011), bird species that have been treated for oiling

include the following:

 Brown Pelican

 White Pelican

 Masked Booby

 Magnificent Frigatebird

 Laughing Gull

 Herring Gull

 Northern Gannet

 Black Crowned Night Heron

 Tri

‐ colored Heron

 Green Heron

 Cattle Egret

 Snowy Egret

 Reddish Egret  Least Bittern

 Common Tern

 Royal Tern

 Caspian Tern

 Sandwich Tern

 Forster’s Tern

 Black Tern

 Gull

‐ billed Tern

 Least Tern

 Black Skimmer

 Black Oystercatcher

 White Ibis

 Roseate SpoonbillEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 52  Willet

 Sanderling

 Dunlin

 Semipalmated Sandpiper  Killdeer

 King Rail

 Clapper Rail

 Virginia Rail

According to the USFWS (2010d), species with the largest numbers of dead oiled birds were

Laughing Gull, Northern Gannet, Brown Pelican, Royal Tern, Black Skimmer, Least Tern,

unidentified Gull, and unidentified Tern. There are no reports of Bald Eagle oiling.

While the Macondo spill had direct and indirect impacts to coastal and marine birds, it is

premature to conclude impacts over a long period (BOEM, 2012). Modeling of Macondo spill

related bird impacts is underway by the NRDA, but results have not yet been released.

Antonio et al. (2011) modeled bird

‐ mortality from the Macondo spill showing cumulative

carcass numbers and mortality rate increasing exponentially from the start of the Macondo spill

until the mortality rate began to decline after the 97th day of the spill. Note that the collected

animals would be a small subset of the total number of impacted birds and therefore, the

collected animals would represent an underestimated measure of the overall impact of the

Deepwater Horizon event (BOEM, 2012).

Coastal birds can be exposed to oil as they float on the water surface, dive during foraging, or

wade in oiled coastal waters. Oiled birds can lose the ability to fly, dive for food, or float on the

water, which could lead to drowning (USFWS, 2010e). Oil interferes with the water repellency

of feathers and can cause hypothermia in the right conditions. As birds groom themselves, they

can ingest and inhale the oil on their bodies. Scavengers such as Bald Eagles and gulls can be

exposed to oil by feeding on carcasses of contaminated fish and wildlife. While ingestion can kill

animals immediately, more often it results in lung, liver, and kidney damage, which can lead to

death. Bird eggs may be damaged if an oiled adult sits on the nest.

As noted above, the Brown Pelican was recently removed from the Federal endangered species

list. Over 300 dead Brown Pelicans were collected in the Gulf following the Macondo spill,

(USFWS, 2010d). These data indicate that Brown Pelicans may be particularly at risk of oiling in

the event of a catastrophic spill reaching coastal waters. Issues for Brown Pelicans include direct

contact with oil, disturbance by cleanup activities, and long

‐ term habitat contamination.



## C.5 Fisheries Resources

C.5.1 Pelagic Communities and Ichthyoplankton

Biggs and Ressler (2000) reviewed the biology of pelagic communities in the deepwater

environment of the northern Gulf of Mexico. The biological oceanography of the region is

dominated by the influence of the Loop Current, whose surface waters are among the most

oligotrophic in the world’s oceans. Superimposed on this low

‐ productivity condition are

productive “hot spots” associated with entrainment of nutrient

‐ rich Mississippi River water and

mesoscale oceanographic features. Anticyclonic and cyclonic hydrographic features play an

important role in determining biogeographic patterns and controlling primary productivity in the

northern Gulf of Mexico (Biggs and Ressler, 2000).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 53 Most fishes inhabiting shelf or oceanic waters of the Gulf of Mexico have planktonic eggs and

larvae (Ditty, 1986; Ditty et al., 1988; Richards et al., 1989, 1993). Pelagic eggs and larvae

become part of the planktonic community for various lengths of time (10 to 100 days,

depending on the species) (MMS, 2007b).

IPFs potentially affecting pelagic communities and ichthyoplankton include drilling rig presence,

noise, and lights; effluent discharges; water intakes; and two types of accidents

‐ a small fuel

spill and a large oil spill (WCD).



### Impacts of Drilling Rig Presence, Noise, and Lights

The drilling rig, as a floating structure in the deepwater environment, will act as a fish

‐ attracting

device (FAD). In oceanic waters, the FAD effect would be most pronounced for epipelagic fishes

such as tunas, dolphin, billfishes, and jacks, which are commonly attracted to fixed and drifting

surface structures (Holland et al., 1990; Higashi, 1994; Relini et al., 1994; MMS, 2000, 2007b,

2008). This FAD effect could possibly enhance the feeding of epipelagic predators by attracting

and concentrating smaller fish species. Because the drilling rig is a single, temporary structure,

impacts on fish populations, whether beneficial or adverse, are considered minor.



### Impacts of Effluent Discharges

Treated sanitary and domestic wastes may have a slight effect on the pelagic environment in the

immediate vicinity of these discharges. These wastes may have elevated levels of nutrients,

organic matter, and chlorine, but should be diluted rapidly to undetectable levels within tens to

hundreds of meters from the source. Minimal impacts on water quality, plankton, and nekton

are anticipated.

Deck drainage may have a slight effect on the pelagic environment in the immediate vicinity of

these discharges. Deck drainage from contaminated areas will be passed through an

oil

‐ and

‐ water separator prior to release, and discharges will be monitored for visible sheen. The

discharges may have slightly elevated levels of hydrocarbons but should be diluted rapidly to

undetectable levels within tens to hundreds of meters from the source. Minimal impacts on

water quality, plankton, and nekton are anticipated.

Other discharges in accordance with the NPDES permit, such as desalination unit brine and

uncontaminated cooling water, fire water, and ballast water, are expected to be diluted rapidly

and have little or no impact on water column biota.



### Impacts of Water Intakes

Seawater will be drawn from the ocean for once

‐ through, non

‐ contact cooling of machinery

on the drilling rig. Rigs considered for use for activities described in this SEP are not “new”

facilities as defined by the NPDES permit and therefore are not subject to the cooling water

intake regulations for Phase III facilities under Section 316(b) of the Clean Water Act.

The intake of seawater for cooling water will entrain plankton. The low intake velocity should

allow most strong

‐ swimming juvenile fishes and smaller adults to escape entrainment or

impingement. However, drifting plankton would not be able to escape entrainment with the

exception of a few fast

‐ swimming larvae of certain taxonomic groups. Those organisms

entrained may be stressed or killed, primarily through changes in water temperature during the

route from cooling intake structure to discharge structure and mechanical damage (turbulenceEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 54 in pumps and condensers). Due to the limited scope and short duration of drilling activities, any

short

‐ term impacts of entrainment are not expected to be biologically significant to plankton or

ichthyoplankton populations.



### Impacts of a Small Fuel Spill

Potential spill impacts on fisheries resources are discussed in recent EISs (MMS, 2007b, 2008).

For this SEP, there are no unique site

‐ specific issues with respect to spill impacts.

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer. In the unlikely event of a spill, implementation of

Anadarko’s OSRP will mitigate the potential for impacts on pelagic communities, including

ichthyoplankton. SEP Section H provides detail on spill response measures. Given the open

ocean location of the lease area, the duration of a small spill and opportunity for impacts to

occur would be very brief.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products. The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions at

the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours. The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

A small fuel spill could have localized impacts on phytoplankton, zooplankton, and nekton. Due

to the limited areal extent and short duration of water quality impacts, a small fuel spill would

be unlikely to produce detectable impacts on pelagic communities.



### Impacts of a Large Oil Spill (WCD)

A large oil spill could affect water column biota including phytoplankton, zooplankton,

ichthyoplankton, and nekton. A large spill that persisted for weeks or months would be more

likely to affect these communities. While adult and juvenile fishes may actively avoid a large

spill, planktonic eggs and larvae would be unable to avoid contact. Eggs and larvae of fishes are

especially vulnerable to oiling and they will die if exposed to certain toxic fractions of spilled oil.

Impacts potentially would be greater if local

‐ scale currents retained planktonic larval

assemblages (and the floating oil slick) within the same water mass.



### C.5.2 Essential Fish Habitat

Essential Fish Habitat (EFH) is defined as those waters and substrate necessary to fish for

spawning, breeding, feeding, and growth to maturity. Under the Magnuson

‐ Stevens Fishery

Conservation and Management Act, as amended, Federal agencies are required to consult on

activities that may adversely affect EFH designated in Fishery Management Plans developed by

the regional Fishery Management Councils.

The BOEM (2012) has reexamined the analysis for fish resources and EFH presented in recent

lease EISs (MMS, 2007a,b), in consideration of the Macondo event. No substantial new

information was found that would alter the impact conclusions for fish resources and EFH

presented in MMS (2007a,b).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 55 The Gulf of Mexico Fishery Management Council (GMFMC) has prepared Fishery Management

Plans for corals and coral reefs, shrimps, stone crab, spiny lobster, reef fishes, coastal migratory

pelagic fishes, and red drum. In 2005, the EFH for these managed species was redefined in

Generic Amendment No. 3 to the various Fishery Management Plans (GMFMC, 2005). The EFH

for most of these GMFMC

‐ managed species is on the continental shelf in waters shallower than

183 m (600 ft). The shelf edge is the outer boundary for coastal migratory pelagic fishes, reef

fishes, and shrimps. EFH for corals and coral reefs includes some shelf

‐ edge topographic

features on the Texas

‐ Louisiana OCS, which is located 38 miles (61 km) north

‐ northeast of the

lease area.

Highly migratory pelagic fishes, which occur as transients in the lease area, are the only

remaining group for which EFH has been identified in the deepwater Gulf of Mexico. Species in

this group, including tunas, swordfishes, billfishes, and sharks, are managed by NMFS. Highly

migratory species with EFH at or near the lease area include the following species and life stages

(NMFS, 2009):

 Atlantic bluefin tuna (spawn, eggs,

larvae, adults)

 Blue marlin (juveniles, adults)

 Longbill spearfish (juveniles, adults)

 Oceanic whitetip shark (all)  Skipjack tuna (spawn, adults)

 Swordfish (larvae, juveniles)

 White marlin (juveniles, adults)

 Yellowfin tuna (spawn, juveniles,

adults)

Recent research indicates the central and western Gulf of Mexico may be important spawning

habitat for Atlantic bluefin tuna, and NMFS (2009) has designated a Habitat Area of Particular

Concern (HAPC) for this species. The HAPC covers much of the deepwater Gulf of Mexico,

including the lease area ( Figure 3 ). The areal extent of the HAPC is approximately 300,000 km 2

(15,000 mi 2 ). The prevailing assumption is that Atlantic bluefin tuna follow an annual cycle of

foraging in June through March off the eastern U.S. and Canadian coasts, followed by migration

to the Gulf of Mexico to spawn in April, May, and June (NMFS, 2009).

On 27 May 2011, after an extensive scientific review, NOAA announced that Atlantic bluefin

tuna currently do not warrant species protection under the ESA. NOAA said the species would

be classified as a species of concern, however, effectively placing bluefin tuna on a watch list as

the agency awaits new data on the impact of a stricter international management regimen.

A new amendment to the original EFH Generic Amendment was finalized in 2005

(GMFMC, 2005). One of the most significant proposed changes in this amendment reduced the

extent of EFH relative to the 1998 Generic Amendment by removing the EFH description and

identification from waters between 100 fathoms and the seaward limit of the Exclusive

Economic Zone (EEZ). The Highly Migratory Species Fisheries Management Plan was amended

in 2009 to update EFH and HAPC to include the bluefin tuna spawning area (NMFS, 2009).

There are current NTLs (2009

‐ G39 and 2009

‐ G40) that provide guidance and clarification of the

regulations with respect to biologically sensitive underwater features and areas and benthic

communities that are considered EFH (MMS, 2009a,b). A new EFH consultation has been

initiated between BOEM’s Gulf of Mexico Region and NOAA’s Southeastern Region. Some

EFH requirements may change with the new agreement. Until the new agreement is in place,East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 56 the 1999 Programmatic Consultation with the elements described above will be followed

(BOEMRE, 2011a; BOEM, 2012).

Other HAPCs have been identified by the GMFMC (2005). These include the Florida Middle

Grounds, Madison

‐ Swanson Marine Reserve, Tortugas North and South Ecological Reserves,

Pulley Ridge, and several individual reefs and banks of the northwestern Gulf of Mexico

( Figure 3 ). The nearest of these is West Flower Garden Bank, located approximately 51 miles

(82 km) northeast of the lease area.

Routine IPFs potentially affecting EFH include drilling rig presence, noise, and lights; effluent

discharges; water intakes; and two types of accidents

– a small fuel spill and a large oil spill

(WCD).



### Impacts of Drilling Rig Presence, Noise, and Lights

The drilling rig, as a floating structure in the deepwater environment, will act as an FAD. In

oceanic waters, the FAD effect would be most pronounced for epipelagic fishes such as tunas,

dolphin, billfishes, and jacks, which are commonly attracted to fixed and drifting surface

structures (Holland et al., 1990; Higashi, 1994; Relini et al., 1994; MMS, 2000, 2007b, 2008).

This FAD effect would possibly enhance feeding of epipelagic predators by attracting and

concentrating smaller fish species. Because the drilling rig is a single, temporary structure, any

impacts on EFH for highly migratory pelagic fishes are considered minor.



### Impacts of Effluent Discharges

Other effluent discharges affecting EFH by diminishing ambient water quality include drilling

muds and cuttings, treated sanitary and domestic wastes, deck drainage, and miscellaneous

discharges such as desalination unit brine and uncontaminated cooling water, fire water, and

ballast water. Impacts on water quality have been discussed previously. No significant impacts

on EFH for highly migratory pelagic fishes are expected from these discharges.



### Impacts of Water Intakes

As noted previously, cooling water intake will cause entrainment and impingement of plankton,

including fish eggs and larvae (ichthyoplankton). Due to the limited scope and short duration of

drilling activities, any short

‐ term impacts on EFH for highly migratory pelagic fishes are not

expected to be biologically significant.



### Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer. In the unlikely event of a spill, implementation of

Anadarko’s OSRP will help diminish the potential for impacts on EFH. SEP Section H provides

detail on spill response measures. Given the open ocean location of the lease area, the duration

of a small spill and opportunity for impacts to occur would be very brief.

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b, 2008). For this SEP,

there are no unique site

‐ specific issues with respect to spill impacts.

A small fuel spill in offshore waters would produce a slick on the water surface and increase the

concentrations of petroleum hydrocarbons and their degradation products. The extent and

persistence of impacts would depend on the meteorological and oceanographic conditions atEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 57 the time and the effectiveness of spill response measures. Section A.9.2 discusses the likely fate

of a small fuel spill and indicates that over 90% would be evaporated or dispersed naturally

within 24 hours. The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions.

A small fuel spill could have localized impacts on EFH for highly migratory pelagic fishes,

including tunas, swordfishes, billfishes, and sharks. These species occur as transients in the

lease area. A spill would also produce short

‐ term impact on water quality in the HAPC for

spawning bluefin tuna, which covers much of the deepwater Gulf of Mexico. The areal extent of

the affected area would represent a negligible portion of the HAPC.

A small fuel spill would not affect EFH for corals and coral reefs, the nearest EFH is located

38 miles (61 km) north

‐ northeast of the lease area. A small fuel spill would float and dissipate

on the sea surface and would not contact these features.



### Impacts of a Large Oil Spill (WCD)

Potential spill impacts on EFH are discussed in recent EISs (MMS, 2007b, 2008). For this SEP,

there are no unique site

‐ specific issues with respect to EFH.

An oil spill in offshore waters would temporarily increase hydrocarbon concentrations on the

water surface and potentially the subsurface as well. Given the extent of EFH designations in

the Gulf of Mexico (GMFMC, 2005; NMFS, 2009), some impact on EFH would be unavoidable.

A large spill could affect the EFH for many managed species including shrimps, stone crab, spiny

lobster, reef fishes, coastal migratory pelagic fishes, and red drum. It would result in adverse

impacts on water quality and water column biota including phytoplankton, zooplankton, and

nekton. In coastal waters, sediments could be contaminated and result in persistent

degradation of the seafloor habitat for managed demersal fish and shellfish species.

The lease area is within the HAPC for spawning Atlantic bluefin tuna (NMFS, 2009). A large spill

could temporarily degrade the HAPC due to increased hydrocarbon concentrations in the water

column, with the potential for lethal or sublethal impacts on spawning tuna. Potential impacts

would depend in part on the timing of a spill, as this species migrates to the Gulf of Mexico to

spawn in April, May, and June (NMFS, 2009).

The topographic features located 38 miles (61 km) north

‐ northeast of the lease area are

designated as EFH under the corals and coral reefs management plan. An accidental spill would

be unlikely to affect this area, since a surface slick would not reach these features due to their

depth.



## C.6 Archaeological Resources

C.6.1 Shipwreck Sites

The BOEMRE (2011a), and BOEM, (2012) reexamined the analyses for archaeological resources

presented in MMS (2007b, 2008), based on additional information available since the

publication of these two documents and in consideration of the Macondo oil spill. Substantial

new information that alters the impact conclusion for archaeological resources presented in

MMS (2007b, 2008) has come to light as a result of BOEM

‐ sponsored studies and industry

surveys. Specifically, evidence of damage to significant cultural resources (i.e., historicEast Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 58 shipwrecks) has been shown to have occurred because of an incomplete knowledge of seafloor

conditions in lease areas >200 m (656 ft) deep that have been exempted from high

‐ resolution

surveys. Since significant historic shipwrecks have recently been discovered outside the

previously designated high

‐ probability areas (some of which show evidence of impacts from

permitted activities prior to their discovery), a survey is now required for exploration and

development projects.

The lease area is not on the list of leases with a high potential for historic shipwrecks. GEMS

(2012) site clearance letters indicated no evidence of shipwrecks or other archaeological

resources near the proposed SHLs. Anadarko will abide by the applicable requirements of

NTL 2005

‐ G07, which stipulate that work be stopped at the project site should any previously

undetected archaeological resource be discovered after work has begun until appropriate

surveys and evaluations have been completed.

Because there are no shipwreck sites in the lease area, there are no routine IPFs that are likely

to affect shipwrecks. The impacts of a large oil spill (WCD) is the only accident IPF considered.

A small fuel spill would not affect shipwrecks because the oil would float and dissipate on the

sea surface.



### Impacts of a Large Oil Spill (WCD)

MMS (2007b) estimated that a severe subsurface blowout could resuspend and disperse

sediments within a 300

‐ m (984

‐ ft) radius. Because there are no historic shipwrecks in the lease

area, this impact would not be relevant.

Previous analyses (MMS, 2007a, 2008) concluded that oil spills would be unlikely to affect

archaeological sites beyond the immediate vicinity of the wellhead (i.e., due to physical impacts

of a blowout) because the oil would rise quickly to the sea surface directly over the spill location.

However, during the Macondo spill, subsurface plumes were reported at a water depth of about

1,100 m (3,600 ft), extending at least 22 miles (35 km) from the wellsite and persisting for more

than a month (Camilli et al., 2010). The subsurface plumes apparently resulted from the use of

dispersants at the wellhead (Joint Analysis Group, 2010c). While the behavior and impacts of

subsurface plumes are not well known, a subsurface plume could have the potential to contact

shipwreck sites beyond the 300

‐ m (984

‐ ft) radius estimated by MMS (2007a, 2008), depending

on its extent, trajectory, and persistence. If oil from a subsea spill should come into contact with

wooden shipwrecks on the seafloor, it could adversely affect their condition or preservation.

Should there be any indication that potential shipwreck sites could be affected, in accordance

with NTL 2005

‐ G07 Anadarko will immediately halt operations, take steps to ensure that the site

is not disturbed in any way, and contact the BOEM Regional Supervisor, Leasing and

Environment, within 48 hours of its discovery. Anadarko would cease all operations within

305 m (1,000 ft) of the site until the Regional Supervisor provides instructions on steps to take

to assess the site’s potential historic significance and protect it.

A spill entering shallow coastal waters could conceivably contaminate an undiscovered

shipwreck site. As noted by MMS (2007b), should an oil spill contact a coastal historic site, such

as a fort or a lighthouse, the major impact would be a temporary, reversible visual impact from

oil contact and contamination of the site and its environment.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 59 

### C.6.2 Prehistoric Archaeological Sites

Available evidence suggests that sea level in the northern Gulf of Mexico was at least 90 m

(295 ft), and possibly as much as 130 m (427 ft), lower than present sea level during the period

20,000 to 17,000 years Before Present (B.P.) (Nelson and Bray, 1970). Sea level in the northern

Gulf reached its present stand around 3,500 years B.P. (Pearson et al., 1986).

During periods that the continental shelf was exposed above sea level, the area was open to

habitation by prehistoric peoples. The advent of early man into the Gulf of Mexico region is

currently accepted to be around 12,000 years B.P. (Aten, 1983). The sea

‐ level curve for the

northern Gulf of Mexico proposed by Coastal Environments, Inc. (CEI) suggests that sea level at

12,000 years B.P. would have been approximately 45 to 60 m (148 to 197 ft) below the

present

‐ day sea level (CEI, 1977, 1982). On this basis, the continental shelf shoreward of the

45

‐ to 60

‐ m (148

‐ to 197

‐ ft) bathymetric contours has potential for prehistoric sites dating after

12,000 years B.P. Because of inherent uncertainties in both the depth of sea level and the entry

date of prehistoric man into North America, the MMS adopted the 60

‐ m (197

‐ ft) water depth as

the seaward extent for archaeological site potential in Gulf of Mexico region.

The wellsites are in water depths ranging from 1,156 to 1,262 m (3,794 to 4,139 ft), which is well

beyond the 60

‐ m (197

‐ ft) depth contour used by the BOEMRE as the seaward extent for

prehistoric archaeological site potential in the Gulf of Mexico. Because prehistoric

archaeological sites are not found in the lease area, the only relevant accident IPF is a large oil

spill (WCD). A small fuel spill would not affect prehistoric archaeological resources because the

oil would float and dissipate on the sea surface.



### Impacts of a Large Oil Spill (WCD)

Because prehistoric archaeological sites are not found in the lease area, they would not be

affected by the physical effects of a subsea blowout. The MMS (2007b) estimates that a severe

subsurface blowout could resuspend and disperse sediments within a 300

‐ m (984

‐ ft) radius.

Along the northern Gulf Coast, prehistoric sites occur frequently along the barrier islands and

mainland coast and along the margins of bays and bayous (MMS, 2007b). If a spill did reach a

prehistoric site along these shorelines it could coat fragile artifacts or site features and

compromise the potential for radiocarbon dating organic materials in a site (although other

dating methods are available and it is possible to decontaminate an oiled sample for

radiocarbon dating). Coastal prehistoric sites could also be damaged by spill cleanup operations

(e.g., by destroying fragile artifacts and disturbing the provenance of artifacts and site features).



## C.7 Coastal Habitats and Protected Areas

Coastal habitats in the northeastern Gulf of Mexico that may be affected by oil and gas activities

are described in recent EISs (MMS, 2007b, 2008) and in a literature review by Collard and Way

(1997). Coastal habitats inshore of the project area include barrier beaches and dunes,

wetlands, and submerged seagrass beds. Generally, most of the northeastern Gulf is fringed by

barrier beaches, with wetlands and/or submerged seagrass beds occurring in sheltered areas

behind the barrier islands and in estuaries.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 60 Due to the distance from shore, the only IPF associated with routine activities in the lease area

that potentially may affect beaches and dunes, wetlands, seagrass beds, coastal wildlife refuges,

wilderness areas, or any other managed or protected coastal area is related to support vessel

traffic. The primary support bases at Fourchon and Houma, Louisiana are not in wildlife refuges

or wilderness areas. Potential impacts of support vessel traffic are addressed briefly below.

A small fuel spill in the lease area would be unlikely to affect coastal habitats, as the lease area is

120 miles (194 km) from the nearest shoreline (Texas). As explained in Section A.9.2

, a small

fuel spill would not be expected to make landfall or reach coastal waters prior to breaking up.



### Impacts of Support Vessel Traffic

For OCS activities in general, support operations, including crew boats and supply boats, may

have a minor incremental impact on coastal habitats. Over time with a large number of vessel

trips, vessel wakes can erode shorelines along inlets, channels, and harbors. Support

operations, including crew boats and supply boats as detailed in SEP Section K

, may have a

minor incremental impact on coastal habitats or protected areas. Impacts will be minimized by

following the speed and wake restrictions in harbors and channels.



### Impacts of a Large Oil Spill (WCD)

Potential spill impacts on coastal habitats are discussed in recent EISs (MMS, 2007b, 2008).

Coastal habitats inshore of the project area include barrier beaches and dunes, wetlands, and

submerged seagrass beds. For this SEP, there are no unique site

‐ specific issues with respect to

coastal habitats.

The revised OSRA modeling summarized in Table 3 predicts that during spring there is a

30% probability of oil from a spill in the lease area reaching shorelines in Texas within 120 days,

and an 8% probability in summer of oil reaching Louisiana shorelines within 120 days.

The shorelines within the geographic range predicted by the OSRA modeling ( Table 3 ) include

extensive barrier beaches and wetlands, with submerged seagrass beds occurring in sheltered

areas behind the barrier islands and in estuaries. NWRs and other protected areas along the

coast are discussed in a recent lease sale EIS (MMS, 2007b) and Anadarko’s OSRP. Coastal and

near coastal wildlife refuges, wilderness areas, and State and National parks within the

geographic range of the potential shoreline contacts after 120 days are presented in Table 6

.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 61 Table 6. Wildlife refuges, wilderness areas, and State and National parks within the geographic

range of the potential shoreline contacts after 120 days (From: BOEM, 2012).

County or Parish Wildlife Refuge, Wilderness Area, or

State/National Park

Cameron County, Texas Lower Rio Grande Valley NWR

Laguna Atascosa NWR

Padre Island National Seashore

Isla Blanca Park

Andy Bowie County Park

Laguna Madre Estuarine and Coastal Marine Area

Willacy County, Texas Lower Rio Grande Valley National Wildlife Reserve

Laguna Atascosa National Wildlife Reserve

Padre Island National Seashore

Laguna Madre Estuarine And Coastal Marine Area

Kenedy County, Texas Padre Island National Seashore

Laguna Madre Estuarine and Coastal Marine Area

Kleberg County, Texas Padre Island National Seashore

Laguna Madre Estuarine and Coastal Marine Area

Nueces County, Texas Laguna Madre Estuarine and Coastal Marine Area

Mustang Island State Park

Lake Corpus Christi State Park

Port Aransas Park

Mission

‐ Aransas National Estuarine Research Reserve

Aransas County, Texas Mission

‐ Aransas National Estuarine Research Reserve

Aransas NWR

Goose Island State Park

Calhoun County, Texas Mission

‐ Aransas National Estuarine Research Reserve

Aransas NWR

Matagorda Island State Park

Guadalupe Delta WMA

Welder Flats Coastal Preserve

Matagorda County, Texas Big Boggy NWR

Aransas NWR

Mad Island WMA

San Bernard NWR

Brazoria County, Texas San Bernard NWR

Peach Point WMA

Brazoria NWR

Christmas Bay Coastal Preserve and Christmas Bay State Park

Galveston County, Texas Galveston Island State Park

Brazoria NWR

Apffel Park

Seawolf Park

Old Fort Travis Park

Atkinson Island WMA

Ft. Anahuc Park

Anahuac NWR

Mcfaddin NWRTable 6. (Continued).

East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 62 County or Parish Wildlife Refuge, Wilderness Area, or

State/National Park

Jefferson County, Texas Mcfaddin NWR

Sea Rim State Park

Murphree WMA

Texas Point NWR

Cameron Parish, Louisiana Sabine NWR

Cameron Prairie NWR

Lacassine NWR

Little Pecan Island Natural Area

Peveto Woods Natural Area

Lower Neches WMA

Rockefeller WMA

Vermilion Parish, Louisiana Louisiana Rockefeller WMA

Paul J. Rainey WMA

Plaquemines Parish, Louisiana Salvador WMA

Jean Lafitte National Historical Park and Preserve

Delta NWR

Pass A Loutre WMA

Breton NWR

St. Bernard State Park

NWR = National Wildlife Refuge; WMA = Wildlife Management Area.

The level of impacts from oil spills on coastal habitats depends on many factors, including the oil

characteristics, the geographic location of the landfall, and the weather and oceanographic

conditions at the time (MMS, 2007b). Oil that makes it to beaches may be either liquid

weathered oil, an oil

‐ and

‐ water mousse, or tarballs (MMS, 2007b). Oil is generally deposited on

beaches in lines defined by wave action at the time of landfall. Oil that remains on the beach

will thicken as its volatile components are lost. Thickened oil may form tarballs or aggregations

that incorporate sand, shell, and other materials into its mass. Tar may be buried to varying

depths under the sand. On warm days, both exposed and buried tarballs may liquefy and ooze.

Oozing may also serve to expand the size of a mass as it incorporates beach materials. Oil on

beaches may be cleaned up manually, mechanically, or both. Some oil can remain on the beach

at varying depths and may persist for several years as it slowly biodegrades and volatilizes.

Wetlands are highly sensitive to oiling. The MMS (2007b) predicted that for every 50 bbl of oil

contacting wetlands, approximately 2.7 ha (6.7 ac) of wetland vegetation will experience

dieback. Thirty percent of these damaged wetlands are assumed to recover within 4 years, and

85% within 10 years. About 15% of the contacted wetlands are expected to be converted

permanently to open

‐ water habitat. The critical concentration of oil is that concentration above

which impacts to wetlands will be long

‐ term and recovery will take longer than two growing

seasons, and which causes plant mortality and some permanent wetland loss. Critical

concentrations of various oils are expected to vary broadly for wetland types and wetland plant

species. Louisiana wetlands are assumed to be more sensitive to oil contact than elsewhere in

the Gulf because of high cumulative stress (MMS, 2007b). In addition to the direct impacts of

oil, cleanup activities in marshes may accelerate rates of erosion and retard recovery rates,

which have been reported to require from years to decades following a spill (MMS, 2007b).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 63 

## C.8 Socioeconomic and Other Resources

C.8.1 Recreational and Commercial Fishing

BOEM has reexamined the analysis for recreational and commercial fishing presented in

MMS (2007b, 2008) based on additional information and in consideration of the Macondo spill.

No new information was found that would alter the potential impacts on commercial fishing

(BOEMRE, 2011a; BOEM, 2012).

The main commercial fishing activity in deep waters of the northern Gulf of Mexico is pelagic

longlining for tunas, swordfishes, and other billfishes (Continental Shelf Associates, Inc., 2002).

Pelagic longlining has occurred historically in the project area, primarily during spring and

summer. In August 2000, the Federal government closed two areas in the northeastern Gulf of

Mexico to longline fishing (65 FR 47214, 1 August 2000). The lease is outside of the closure

areas.

Longline gear consists of monofilament line deployed from a moving vessel and generally

allowed to drift for 4 to 5 hours (Continental Shelf Associates, Inc., 2002). As the mainline is put

out, baited leaders and buoys are clipped in place at regular intervals. It takes 8 to 10 hours to

deploy a longline and about the same time to retrieve it. Longlines are often set near

oceanographic features such as fronts or downwellings, with the aid of sophisticated on

‐ board

temperature sensors, depth finders, and positioning equipment. Vessels typically are 10 to 30 m

(33 to 98 ft) long, and their trips last from about 1 to 3 weeks. The main Gulf of Mexico

homeports for longlining vessels are in Louisiana (Dulac and Venice) and Florida (Destin,

Madeira Beach, and Panama City).

It is unlikely that any commercial fishing activity other than longlining occurs at or near the

project area. Benthic species targeted by commercial fishers occur on the upper continental

slope, well inshore of the project area. Royal red shrimp are caught by trawlers in water depths

of about 250 to 550 m (820 to 1,804 ft). Tilefish are caught by bottom longlining in water

depths from about 165 to 450 m (540 to 1,476 ft) (Continental Shelf Associates, Inc., 2002).

Most recreational fishing activity in the region occurs in water depths less than 200 m (656 ft)

(Continental Shelf Associates, Inc., 1997, 2002). In deeper water, the main attraction to

recreational fishers would be petroleum rigs offshore Texas and Louisiana. Due to the distance

from shore, it is unlikely that recreational fishing activity is occurring in the lease area.

The only routine IPF potentially affecting fisheries is drilling rig presence (including noise and

lights). Two potential types of accidents are also addressed below

– a small fuel spill and a large

oil spill (WCD).



### Impacts of Drilling Rig Presence

There is a slight possibility of pelagic longlines becoming entangled in the drilling rig. For

example, in January 1999, a portion of a pelagic longline snagged on the acoustic Doppler

current profiler of a drillship working in the Gulf of Mexico (Continental Shelf Associates, Inc.,

2002). The line was removed without incident. Generally, longline fishers use radar and are

aware of offshore structures and ships when placing their sets. Therefore, little or no impact on

pelagic longlining is expected.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 64 Because it is unlikely that any recreational fishing activity is occurring in the project area, no

adverse impacts are anticipated. Other factors such as effluent discharges are likely to have

negligible impacts on commercial or recreational fisheries due to rapid dispersion, the small

area of ocean affected, and the intermittent nature of the discharges.



### Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer. In the unlikely event of a spill, implementation of

Anadarko’s OSRP will potentially mitigate and reduce the potential for impacts. SEP Section H

provides detail on spill response measures. Given the open ocean location of the lease area, the

duration of a small spill and opportunity for impacts to occur would be very brief.

Pelagic longlining activities in the lease area, if any, could be interrupted in the event of a small

fuel spill. The area of the sea surface with diesel fuel on it would range from 0.5 to 5 ha

(1.2 to 12 ac), depending on sea state and weather conditions. Fishing activities could be

interrupted due to the activities of response vessels operating in the lease area. A small fuel

spill would not affect coastal water quality because the spill would not be expected to make

landfall or reach coastal waters prior to breaking up (see Section A.9.2 ).



### Impacts of a Large Oil Spill (WCD)

Potential spill impacts on fishing activities are discussed in recent EISs (MMS, 2007b, 2008). For

this SEP, there are no unique site

‐ specific issues with respect to this activity.

Pelagic longlining activities in the lease area and other fishing activities in the northern Gulf of

Mexico could be interrupted in the event of a large oil spill. A spill may or may not result in

fishery closures, depending on the duration of the spill, the oceanographic and meteorological

conditions at the time, and the effectiveness of spill response measures. The recent Macondo

spill provides information about the maximum potential extent of fishery closures in the event

of a large oil spill in the Gulf of Mexico (NMFS, 2010d). At its peak on 12 July 2010, closures

encompassed 217,821 km 2 (84,101 mi 2 ), or 34.8% of the U.S. Gulf of Mexico EEZ.



### C.8.2 Public Health and Safety

There are no IPFs associated with routine operations that are expected to affect public health

and safety. Impacts of a small fuel spill and a large oil spill (WCD) are addressed below.



### Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer. In the unlikely event of a spill, implementation of

Anadarko’s OSRP will potentially alleviate the potential for impacts. SEP Section H provides

detail on spill response measures.

A small fuel spill would not have any impacts on public health and safety because it would affect

only a small area of the open ocean 120 miles (194 km) from the nearest shoreline (Texas) and

nearly all of the diesel fuel would evaporate or disperse naturally within 24 hours. Response

crews would be equipped with appropriate safety equipment to avoid injury and health effects.

A small fuel spill would not be expected to make landfall or reach coastal waters prior to

breaking up (see Section A.9.2 ).East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 65 

### Impacts of a Large Oil Spill (WCD)

In the event of a large spill from a blowout, the main safety and health concerns are those of the

offshore personnel involved in the incident and those responding to the spill. The drilling rig

maintains a Shipboard Oil Pollution Emergency Plan as required under MARPOL 73/78.

Depending on the spill rate and duration, the physical/chemical characteristics of the oil,

meteorological and oceanographic conditions at the time, and the effectiveness of spill response

measures, the public could be exposed to oil on the water and along the shoreline, including

skin contact or breathing VOCs. Crude oil is a highly flammable material, and any smoke or

vapors from a crude oil fire can cause irritation, and in large quantities may pose a health

hazard.

Data from the recent Macondo spill provide relevant information about the types of health

issues that may occur in the event of a large oil spill (Centers for Disease Control and Prevention,

2010a). Wildlife cleaning and rehabilitation workers have reported concerns including scrapes

and cuts, itchy or red skin or rash, and symptoms of headache or feeling faint, dizzy, or fatigued.

Hand, shoulder, or back pain was also reported by some wildlife

‐ cleaning workers. Personnel

working on offshore vessels or providing direct oversight to offshore vessels, including

USCG personnel, civilian contractors, and other responders who were exposed to oil and

dispersants, had a 7 to 12 times higher prevalence of upper respiratory symptoms and cough

than those not exposed (Centers for Disease Control and Prevention, 2010b). Another potential

occupational hazard for spill response workers in general was heat stress from work in a hot and

humid environment. Initial symptoms from cleanup workers who sought medical care in

Louisiana were typical of acute exposure to hydrocarbons or H 2 S such as headaches, dizziness,

nausea, vomiting, cough, respiratory distress, and chest pain (Solomon and Janssen, 2010).



### C.8.3 Employment and Infrastructure

There are no IPFs associated with routine operations that are expected to affect employment

and infrastructure. The project involves drilling with support from existing shorebase facilities in

Louisiana. No new or expanded facilities will be constructed, and no new employees are

expected to move permanently into the area. The project will have a negligible impact on

socioeconomic conditions such as local employment, existing offshore and coastal infrastructure

(including major sources of supplies, services, energy, and water), and minority and lower

income groups. Impacts of a small fuel spill and a large oil spill (WCD) are addressed below.



### Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer. In the unlikely event of a spill, implementation of

Anadarko’s OSRP will potentially mitigate and reduce the potential for impacts. SEP Section H

provides detail on spill response measures. Given the open ocean location of the lease area, the

duration of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill that is dissipated within a few days would have little or no economic impact, as

the spill response would use existing facilities, resources, and personnel.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 66 

### Impacts of a Large Oil Spill (WCD)

Potential socioeconomic impacts of an oil spill are discussed in recent EISs (MMS, 2007b, 2008).

For this SEP, there are no unique site

‐ specific issues with respect to employment and coastal

infrastructure. A large spill could cause economic impacts in several ways: it could result in

extensive fishery closures that put fishermen out of work; it could result in temporary

employment as part of the response effort; it could result in adverse publicity that affects

employment in coastal recreation and tourism industries; and it could result in another

suspension of OCS drilling activities, including service and support operations that are an

important part of local economies.

In addition to the analyses presented by MMS (2007b, 2008) and BOEM (2012), a recent study

explored the economic impacts of the Macondo spill on oil and gas industry employment due to

suspension of deepwater drilling (Inter

‐ Agency Economic Report, 2010). The study indicates

that during the moratorium, the number of oil industry workers in the Gulf of Mexico fell by

about 2,000 and may have indirectly caused a temporary loss of 8,000 to 12,000 jobs along the

Gulf Coast. Total spending by drilling operators is estimated to have declined by $1.8 billion

over a six

‐ month period; this direct reduction in spending affected employment in the industries

that supply the Gulf drilling industry and in all other industries affected by declines in consumer

and business spending (Inter

‐ Agency Economic Report, 2010).



### C.8.4 Recreation and Tourism

BOEM has reexamined the analyses for recreation and tourism presented in MMS (2007b, 2008)

based on additional information and in consideration of the Macondo oil spill event. No new

information was found that would alter the potential impacts on recreation and tourism

(BOEMRE, 2011a; BOEM, 2012).

There are no known recreational uses of the lease area. Recreational resources and tourism in

coastal areas would not be affected by any routine activities due to the distance from shore.

Compliance with NTL 2012

‐ BSEE

‐ G01 will minimize the chance of trash or debris being lost

overboard from the drilling rig and subsequently washing up on beaches.



### Impacts of a Small Fuel Spill

The probability of a fuel spill will be minimized by Anadarko’s preventative measures during

routine operations including fuel transfer. In the unlikely event of a spill, implementation of

Anadarko’s OSRP will potentially help mitigate and reduce the potential for impacts.

SEP Section H provides detail on spill response measures. Given the open ocean location of the

lease area, the duration of a small spill and opportunity for impacts to occur would be very brief.

A small fuel spill in the lease area would be unlikely to affect recreation and tourism. There are

no known recreational or tourism activities occurring in the lease area, and as explained in

Section A.9.2

, a small fuel spill would not be expected to make landfall or reach coastal waters

prior to breaking up.



### Impacts of a Large Oil Spill (WCD)

Potential impacts of an oil spill on recreation and tourism are discussed in recent EISs

(MMS, 2007b, 2008). For this SEP, there are no unique site

‐ specific issues with respect to these

impacts.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 67 Impacts on recreation and tourism would vary depending on the duration of the spill and its fate

including the effectiveness of response measures. A large spill that reached coastal waters and

shorelines could adversely affect recreation and tourism by contaminating beaches and

wetlands, resulting in negative publicity that encourages people to stay away. Based on the

revised OSRA modeling (BOEM, 2012) as summarized in Section A.9.3 ( Table 3 ), there is a

30% probability in spring of oil from a spill in the lease area reaching shorelines in Texas and an

8% chance in summer of contacting shorelines in Louisiana within 120 days.

In addition to the analysis presented by MMS (2007b, 2008), recent and ongoing studies have

explored the economic impacts of the Macondo spill including tourism and “brand” damage

(IEM, 2010; Oxford Economics, 2010). The U.S. Travel Association has estimated the economic

impact of the Macondo spill on tourism across the Gulf Coast over a three

‐ year period at

$22.7 billion (Oxford Economics, 2010).



### C.8.5 Land Use

Land use along the northern Gulf Coast is discussed in recent lease sale EISs (MMS, 2007b,

2008). There are no routine IPFs potentially affecting land use. The project will use existing

onshore support facilities in Louisiana. The land use at the existing shorebase sites is industrial.

The project will not involve any new construction or changes to existing land use and, therefore,

will not have any impacts. Levels of boat and helicopter traffic, as well as demand for goods and

services including scarce coastal resources, will represent a small fraction of the level of activity

occurring at the shorebases.

A large oil spill (WCD) is the only relevant accident IPF. A small fuel spill would not have any

impacts on land use, as the response would be staged out of existing shorebases and facilities.



### Impacts of a Large Oil Spill (WCD)

The initial response for a large oil spill would be staged out of existing facilities, with no effect on

land use. A large spill could have limited temporary impacts on land use along the coast if

additional staging areas were needed. For example, during the Macondo spill, temporary

staging areas were established in Louisiana, Mississippi, Alabama, and Florida for spill response

and cleanup efforts. In the event of a large spill in the lease area, similar temporary staging

areas could be needed. These areas would eventually return to their original use as the

response is demobilized.



### C.8.6 Other Marine Uses

The lease area is located within Military Warning Areas W

‐ 602 and W

‐ 147E and Anadarko will

comply with BOEM requirements and lease stipulations to avoid impacts on military vessels and

aircraft operating in or near the lease site. There are existing wells and Anadarko pipelines

within 610 m (2,000 ft) of the proposed wellsites (GEMS, 2012) and Anadarko will avoid these.

There are no IPFs from routine project activities that are likely to affect other marine uses of the

lease area. A large oil spill (WCD) is the only relevant accident IPF. A small fuel spill would not

have any impacts on other marine uses because spill response activities would be mainly within

the lease area and the duration would be brief.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 68 

### Impacts of a Large Oil Spill (WCD)

An accidental spill would be unlikely to significantly affect shipping or other marine uses. The

blocks are not located within any USCG

‐ designated fairway or shipping lane. In the event of a

large spill requiring numerous response vessels, coordination would be required to manage the

vessel traffic for safe operations. Anadarko will comply with BOEM requirements and lease

stipulations to avoid impacts on uses of the area by military vessels and aircraft.

In the event of a large spill requiring numerous vessels in the area, coordination would be

required to ensure that no anchoring or seafloor

‐ disturbing activities occur near the existing

pipelines and flowlines.



## D. Environmental Hazards

D.1 Geologic Hazards

Site clearance letters prepared by GEMS (2012) concluded that the wellsites are free of any

significant geological hazards and are suitable for the proposed activities. Caution is advised

when drilling through seafloor faults and avoidance of seafloor mounds is recommended.

See SEP Section C for supporting geological and geophysical information.



## D.2 Severe Weather

Under most circumstances, weather is not expected to have any effect on the proposed

activities. Extreme weather, including high winds, strong currents, and large waves, was

considered in the design criteria for the drilling rigs under consideration for this project. High

winds and limited visibility during a severe storm could disrupt support activities (vessel and

helicopter traffic) and make it necessary to suspend some activities on the drilling rig for safety

reasons until the storm or weather event passes. In the event of a hurricane, procedures as

outlined in the Hurricane Evacuation Plan would be adhered to.



## D.3 Currents and Waves

Metocean conditions such as sea states, wind speed, ocean currents, etc. will be continuously

monitored. Under most circumstances, physical oceanographic conditions are not expected to

have any effect on the proposed activities. Strong currents (e.g., caused by Loop Current eddies

and intrusions) and large waves were considered in the design criteria for the drilling rigs under

consideration for this project. High waves during a severe storm could disrupt support activities

(i.e., vessel and helicopter traffic) and make it necessary to suspend some activities on the

drilling rig for safety reasons until the storm or weather event passes.East Breaks Blocks 645, 689, and 690 May 2012

Environmental Impact Analysis for Supplemental Exploration Plan Page 69 

## E. Alternatives

No formal alternatives were evaluated in this EIA for an SEP. However, various technical and

operational options, including the location of the wellsites and the selection of a drilling unit,

were considered by Anadarko in developing the proposed action.



## F. Mitigation Measures

The proposed action includes numerous mitigation measures required by laws, regulations, and

BOEM lease stipulations and NTLs. The project will comply with all applicable Federal, State,

and local requirements concerning air pollutant emissions, discharges to water, and solid waste

disposal. All project activities will be conducted under guidance by Anadarko’s OSRP and will

include the measures described in SEP Section H

.



## G. Consultation

No persons or agencies were consulted during the preparation of this EIA.



## H. Preparers

The EIA was prepared by CSA International, Inc. Contributors included

 Carlyle Kalloo (Senior Scientist);

 M. John Thompson (Senior Scientist);

 Neal Phillips, Ph.D. (Senior Scientist);

 Luis Lagera, Jr., Ph.D. (Senior Scientist);

 Keith VanGraafeiland (GIS/Remote Sensing Specialist);

 Kristen L. Metzger (Library and Information Services Director); and

 Danielle Johnson (Technical Editor).



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### O

ADMINISTRATIVE INFORMATION

(a) Proprietary Information

Proprietary copies of this plan contain inform ation not available to the public and include

structure maps, seismic information, cross sections, depths of wells, etc.

(b) Bibliography

 Shallow Hazards Reports previously submitted with Plan Control No:

N-9591, N-4734, N-7162

 Site Clearance Letters incl uded with this EP submittal

 Final Sale Package for Western Gulf of Mexico Lease Sale 207