D 

HYDROGEN SULFIDE INFORMATION 

The objective sands to be developed within the Heidelberg Complex GC 859/GC 903 are 

correlative with sands that have been penetrated within the Tahiti complex to the north (GC 

596/GC640/GC 641). They have also been penetrated within the closer offsetting Caesar Tonga 

complex (GC 683/GC726/GC727/GC770/GC771), as well as in the GC 859-1 discovery well 

and GC 903-3 delineation well in Heidelberg. All in all the objective sand intervals have been 

penetrated in over 30 wells within this mini-basin in Green Canyon. To our knowledge, none of 

the wells listed above have encountered H2S in any of the intervals penetrated. 

Since no (H2S) was encountered in any of these wells, Anadarko hereby requests the area 

be classified as a "zone where the absence of H2s has been confirmed.”
 

E 

 BIOLOGICAL, PHYSICAL, AND SOCIOECONOMIC INFORMATION 

(a) Chemosynthetic Communities Report 

The seafloor disturbing activities proposed in this plan are in approximately 5,268’ - 5,355’ of water. The 

wells will be drilled with a DP Drillship or DP Semisubmersible drilling unit. 

Maps 

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

features, and surface location of the proposed well is included in Section A. 

Analysis 

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

within 2000 feet of each proposed muds and cuttings discharge location. 

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

within 250 feet of any seafloor disturbances. 

(b) Topographic Features Map 

The proposed activities are not within 1,000 feet of a no-activity zone or within the 3-mile radius 

zone of an identified topographic feature. Therefore, no map is required 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 identified topographic feature. Therefore, the topographic features 

statement required by NTL No. 2008-G04 is not applicable. 

(d) Live Bottoms (Pinnacle Trend) Map 

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

vertical relief equal to or greater than 8 feet. Therefore, no map is required per NTL No. 2008-

G04. 

(e) Live Bottoms (Low Relief) Map 

The activities proposed in this plan are not within 100 feet 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 plan are not within 200 feet of any potentially sensitive biological 

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

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

Green Canyon Blocks 859 & 903 are located within Deepwater Grid Area 10. This grid is 

considered to have “adequate ROV survey coverage”, and therefore, under the guidance set out 

in NTL No. 2008-G06, a Remotely Operated Vehicle Monitoring Survey Plan is not required. 

(h) Threatened and Endangered Species Information 

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

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

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

In accordance with the 30 CFR 250, Subpart B, effective May 14, 2007, and further outlined in 

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

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

habitat designated under the ESA and marine mammals 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 that one or more of these species could be seen 

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

threatened species 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 

Sei whale Balaenoptera borealis E Xa -- None 

Blue whale Balaenoptera musculus E Xa -- None 

Fin whale Balaenoptera physalus E Xa -- None 

North Atlantic right whale Eubalaena glacialis E Xa -- None 

Humpback whale Megaptera novaeangliae E Xa -- None 

Sperm whale Physeter macrocephalus E X -- None 

West Indian manatee Trichechus manatus latirostris E -- X Florida (Peninsular) 

Sea Turtles 

Loggerhead turtle Caretta caretta T X X None 

Green turtle Chelonia mydas T, Eb X X None 

Leatherback turtle Dermochelys coriacea E X X None 

Hawksbill turtle Eretmochelys imbricata E X X None 

Kemp’s ridley turtle Lepidochelys kempii 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 Acropora palmata E -- 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.

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 

Green Canyon Blocks 859 & 903 are not located in an area designated as having high archaeological potential and, 

as such, an Archaeological Report is not required per NTL No. 2011-JOINT-G01. However, an Archaeological 

Report prepared by Fugro Geoservices, Inc covering the proposed Green Canyon Blocks 859 & 903 well locations 

will be submitted along with this Supplemental Exploration Plan. The survey was conducted in accordance with the 

latest guidelines established by the BOEMRE in 2011. 

(j) Air and Water Quality Information

This EP does not propose activities for which the State of Florida is an affected 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 located offshore Florida. Therefore, socioeconomic information required 

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

F 

WASTE AND DISCHARGE INFORMATION 

The following estimates were prepared utilizing Anadarko’s experience with similar drilling operations. 

Estimated maximum discharge rates are reflected below. Projected amounts may vary during the course 

of drilling and/or completion operations. 

(a) Projected Generated Wastes 

Type of Waste Composition Projected Amount Treatment/Storage/Disposal 

Synthetic-based 

drilling fluids 

Synthetic-based drilling 

muds 

13,000 bbls/well Re-use and/or transport to shore in 

DOT approved containers to 

Fourchon, Louisiana and on to 

base/transfer station. If recycled, 

returned to vendor (Bariod or MI). 

Cuttings wetted with 

synthetic-based fluids 

Cuttings coated with 

synthetic drilling 

muds/fluids, including 

drilled out cement 

6,500 bbls/well

 

 

 

 

Treated and discharge 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) 

74,000 bbls/well** Discharge overboard or at seafloor 

Cuttings wetted with 

water-based fluids 

Cuttings coated with 

water-based drilling 

muds/fluids 

3,800 bbls/well Discharge overboard 

Chemical product 

waste (well treatment 

fluids) 

Ethylene glycol 

Methanol 

7,487 bbls total *** 

1,872 bbls total*** 

Transport to shore in DOT approved 

containers to Fourchon, Louisiana for 

pick up. 

Completion Fluids Brine, spent acid, prop 

sand, debris 

3,000 bbls/well*** Transport to shore in DOT approved 

containers 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 DOT approved 

containers to Fourchon, Louisiana and 

on to Newpark Base. 

Trash and debris Refuse generated during 

operations 

3,777 bbls total Transport to shore in disposal bags by 

vessel to shorebase for pickup by 

municipal operations. 

*Sanitary Wastes Treated human body 

waste 

11,330,000 gals total Chlorinate and discharge overboard 

*Domestic Waste Gray water 11,330,000 gals total Chlorinate and discharge overboard 

Deck drainage Platform washings and 

rainwater 

7,931,000 bbls total Treat for oil and grease and discharge 

overboard 

Produced water N/A N/A N/A 

Desalinization Unit Seawater 793,100 bbls total Discharge overboard 

Wash water Drill water (fresh) 113,300 bbls total Discharge overboard 

Blowout preventer 

fluid 

Blend (3% Stack Magic 

& Filtered Fresh Water) 

299,436 gals total Discharge at seafloor 

Ballast water Seawater 47,650 m3/year Discharge overboard 

Bilge water Seawater 718,322 bbls total Discharge overboard through 15 ppm 

equipment 

Excess cement at the 

seafloor 

Nitrified cement slurry 1200 bbls/well Discharge at seafloor 
 

Fire water Seawater 137,142 bbls/day/well Discharge overboard 

Cooling water Seawater 137,142 bbls/day/well Discharge overboard 

Produced Sand N/A N/A N/A 

Used oil Excess oil from engines 8,120 bbls total Transport in DOT approved containers 

to shore for recycling 

*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 personnel onboard during drilling and/or completion operations. 

**The actual volume ordered out will be an estimated 21,000 bbls/well of mud. Once on location this volume will be cut back 

and mixed with seawater to different desired mud weights which will increase the volume that is discharged at the seafloor. The 

estimated volume that will be discharged at the seafloor will be approximately 74,000 bbls/well (NOTE: there will be twelve 

wells for a total of 888,000 bbls). 

***This type of waste will not exist for the proposed GC 859 “J” and GC 903 “E” locations since only top-hole drilling for these 

wells will occur under this plan. This type of waste will only occur for the additional 10 well locations proposed in GC 859 and 

903 since these wells will be drilled to total depth and completed under this plan. 

(b) Projected Ocean Discharges

Type of Waste Total Amount to be 

Discharged 

Discharge Rate Discharge Method 

*Sanitary Wastes 11,330,000 gals total 25 gals per person daily Chlorinate and discharge overboard 

*Domestic waste 11,330,000 gals total 25 gals per person daily Chlorinate and discharge overboard 

Deck drainage 7,931,000 bbls total 3500 bbls/day Treat for oil and grease and discharge 

Blowout preventer fluid 299,436 gals total 925 gals/week/well; 

Vents on a weekly basis 

Discharge at seafloor 

Desalinization Unit 793,100 bbls total 350 bbls/day Discharge overboard 

Wash water 113,300 bbls total 50 bbls/day Discharge overboard 

Ballast water 47,650 m3/year Not continuous Discharge overboard 

Bilge water 718,322 bbls total 317 bbls/day Discharge overboard through 15 ppm 

equipment 

Excess cement at the 

seafloor 

14,400 bbls total 20 bbls/min Discharge at seafloor 

Fire water 310,763,772 bbls total 137,142 bbls/day Discharge overboard 

Cooling water 310,763,772 bbls total 137,142 bbls/day Discharge overboard 

Cuttings wetted with Waterbased fluids 45,600 bbls total 1,000 bbls/hr max Discharge overboard 

Water-based drilling fluids 888,000 bbls total** 1,000 bbls/hr max Discharge at seafloor or overboard 

Cuttings wetted with 

Synthetic-based fluids 

78,000 bbls total NA Treated and discharge 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. 

Non-pollutant completion 

fluids 

50,000 bbls total*** 100 bbl/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 personnel onboard during drilling and/or completion operations. 

**The actual volume ordered out will be an estimated 21,000 bbls/well of mud. Once on location this volume will be cut back 

and mixed with seawater to different desired mud weights which will increase the volume that is discharged at the seafloor. The 

estimated volume that will be discharged at the seafloor will be approximately 74,000 bbls/well (NOTE: there will be twelve 

wells for a total of 888,000 bbls). 

***This type of waste will not exist for the proposed GC 859 “J” and GC 903 “E” locations since only top-hole drilling for these 

wells will occur under this plan. This type of waste will only occur for the additional 10 well locations proposed in GC 859 and 

903 since these wells will be drilled to total depth and completed under this plan. 

 (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 = 3400D2/3 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? 

Yes 

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

Do you expect to encounter H2S 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 actual fuel usage from contracted drilling units. 

Actual fuel usage was calculated using data from the Ensco 8500 and Trans Ocean Discoverer Spirit rigs. 

A different rig could possibly be utilized but the actual fuel usage/air emissions will be equal to or less 

than the calculated plan emission amounts shown below. Air emissions worksheets are enclosed as 

Attachment G-1. 

(c) Summary Information 

The following tables summarize information regarding the peak year emissions generated from the Plan 

Emissions and Complex Total Emissions: 

If drilled with a DP Semisubmersible (Horsepower equal to or less than the Ensco 8500): 

Air Pollutant Plan Emission 

Amounts1

 (tons)

Calculated 

Exemption 

Amounts2

 (tons)

Calculated Complex 

Total Emission 

Amounts3

 (tons)

Particulate matter (PM) 73.40 4495.50 N/A 

Sulphur dioxide (SO2) 336.70 4495.50 N/A 

Nitrogen oxides (NOx) 2525.00 4495.50 N/A 

Volatile organic compounds (VOC) 77.50 4495.50 N/A 

Carbon monoxide (CO) 562.12 89474.94 N/A 

If drilled with a DP Drillship (Horsepower equal to or less than the T.O. Discoverer Spirit): 

Air Pollutant Plan Emission 

Amounts1

 (tons)

Calculated 

Exemption 

Amounts2

 (tons)

Calculated Complex 

Total Emission 

Amounts3

 (tons)

Particulate matter (PM) 111.06 4495.50 N/A 

Sulphur dioxide (SO2) 509.50 4495.50 N/A 

Nitrogen oxides (NOx) 3819.82 4495.50 N/A 

Volatile organic compounds (VOC) 116.34 4495.50 N/A 

Carbon monoxide (CO) 844.60 89474.94 N/A 
 

The air emission calculations were calculated by: 

Jill Fowler 

Regulatory Analyst 

(832) 636-1554 

jill.fowler@anadarko.com 
EXPLORATION PLAN (EP)

AIR QUALITY SCREENING CHECKLIST

O

OMB Approval Ex

COMPANY Anadarko Petroleum Corporation

AREA Green Canyon

BLOCK 859 & 903LEASE OCS-G 24194 & 24197

PLATFORMWELL GC903 "D & DD, E" and GC 859 "F, G, H, FF, GG, HH, I, II, J"COMPANY CONTACT Jill FowlerTELEPHONE NO. 832-636-1554REMARKS Drill and complete 10 wells, and conduct 2 topsets

Form MMS-138 (May 2001)Page 1 of 8
EMISSIONS FACTORS

Fuel Usage Conversion Factors Natural Gas Turbines Natural Gas Engines Diesel Recip. Engine R

SCF/hp-hr 9.524 SCF/hp-hr 7.143 GAL/hp-hr 0.0483 AP4

Equipment/Emission Factors units PM SOx NOx VOC CO RNG Turbines gms/hp-hr 0.00247 1.3 0.01 0.83 AP42 3NG 2-cycle lean gms/hp-hr 0.00185 10.9 0.43 1.5 AP4NG 4-cycle lean gms/hp-hr 0.00185 11.8 0.72 1.6 AP4NG 4-cycle rich gms/hp-hr 0.00185 10 0.14 8.6 AP4

Diesel Recip. < 600 hp. gms/hp-hr 1 1.468 14 1.12 3.03 AP4

Diesel Recip. > 600 hp. gms/hp-hr 0.32 1.468 11 0.33 2.4 AP4Diesel Boiler lbs/bbl 0.084 2.42 0.84 0.008 0.21 AP42 NG Heaters/Boilers/Burners lbs/mmscf 7.6 0.593 100 5.5 84 P42 1.4-NG Flares lbs/mmscf 0.593 71.4 60.3 388.5 AP4Liquid Flaring lbs/bbl 0.42 6.83 2 0.01 0.21 AP42 1Tank Vapors lbs/bbl 0.03 E&P Fugitives lbs/hr/comp. 0.0005 APGlycol Dehydrator Vent lbs/mmscf 6.6 LaGas Venting lbs/scf 0.0034

Sulfur Content Source Value Units

Fuel Gas 3.33 ppm

Diesel Fuel 0.4 % weight

Produced Gas( Flares) 3.33 ppm

Produced Oil (Liquid Flaring) 1 % weight

Form MMS-138 (May 2001)Page 2 of 8
EMISSIONS CALCULATIONS 1ST YEAR

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum CorporaGreen Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FF, Jill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

DRILLING PRIME MOVER>600hp diesel 21,532 1039.9956 24959.89 24 350 15.18 69.62 521.70 15.65 113.83 63.74 Ensco 8506 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 150 10.44 47.87 358.71 10.76 78.26 4.70 2 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 100 6.53 29.96 224.51 6.74 48.98 1.96 

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

MISC. BPD SCF/HR COUNTTANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 Completion GAS FLARE 625000 24 0 0.37 44.63 37.69 242.81 

2014 YEAR TOTAL 32.14 147.83 1149.54 70.84 483.89 70.40 

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4495.50 

135.0

Form MMS-138 (May 2001)Page 3 of 8
EMISSIONS CALCULATIONS 2ND YEAR

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum CorGreen Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FF, GJill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM S

DRILLING PRIME MOVER>600hp diesel 21,532 1039.9956 24959.89 24.00 365.00 15.18 69.62 521.70 15.65 113.83 66.47 30Ensco 8506 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0AUXILIARY EQUIP<600hp diesel 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6.00 156 10.44 47.87 358.71 10.76 78.26 4.88 22 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6.00 104 6.53 29.96 224.51 6.74 48.98 2.04 9

VESSELS>600hp diesel(tugs) 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

VESSELS>600hp diesel(crew) 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0VESSELS>600hp diesel(supply) 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0

MISC. BPD SCF/HR COUNTTANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

Completion GAS FLARE 625000 24 4 0.37 44.63 37.69 242.81 0

2015 YEAR TOTAL 32.14 147.83 1149.54 70.84 483.89 73.40 33

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4495.50 44

135.0

Form MMS-138 (May 2001)Page 4 of 8
EMISSIONS CALCULATIONS 3RD YEAR

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum CorGreen Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FF, GJill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM S

DRILLING PRIME MOVER>600hp diesel 21,532 1039.9956 24959.89 24 365 15.18 69.62 521.70 15.65 113.83 66.47 30Ensco 8506 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 156 10.44 47.87 358.71 10.76 78.26 4.88 22 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 104 6.53 29.96 224.51 6.74 48.98 2.04 9

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

MISC. BPD SCF/HR COUNT

TANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

Completion GAS FLARE 625000 24 2 0.37 44.63 37.69 242.81 0

2016 YEAR TOTAL 32.14 147.83 1149.54 70.84 483.89 73.40 33

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4495.50 44

135.0

Form MMS-138 (May 2001)Page 5 of 8
EMISSIONS CALCULATIONS 4TH YEAR

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum CorpGreen Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FF, GG Jill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

DRILLING PRIME MOVER>600hp diesel 21,532 1039.9956 24959.89 24 365 15.18 69.62 521.70 15.65 113.83 66.47 Ensco 8506 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 156 10.44 47.87 358.71 10.76 78.26 4.88 2 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 104 6.53 29.96 224.51 6.74 48.98 2.04 

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 MISC. BPD SCF/HR COUNT

TANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

Completion GAS FLARE 625000 24 4 0.37 44.63 37.69 242.81 

2017 YEAR TOTAL 32.14 147.83 1149.54 70.84 483.89 73.40 

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4495.50 

135.0

Form MMS-138 (May 2001)Page 6 of 8
EMISSIONS CALCULATIONS 5TH YEAR

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum CorpGreen Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FF, GG Jill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

DRILLING PRIME MOVER>600hp diesel 21,532 1039.9956 24959.89 24 365 15.18 69.62 521.70 15.65 113.83 66.47 Ensco 8506 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 156 10.44 47.87 358.71 10.76 78.26 4.88 2 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 104 6.53 29.96 224.51 6.74 48.98 2.04 

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 MISC. BPD SCF/HR COUNT

TANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

Completion GAS FLARE 625000 24 2 0.37 44.63 37.69 242.81 

2018 YEAR TOTAL 32.14 147.83 1149.54 70.84 483.89 73.40 

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4495.50 

135.0

Form MMS-138 (May 2001)Page 7 of 8
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum Cor Green Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FJill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR ESTIM

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM SOx 

DRILLING PRIME MOVER>600hp diesel 21,532 1039.9956 24959.89 24 365 15.18 69.62 521.70 15.65 113.83 66.47 304.95 Ensco 8506 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 156 10.44 47.87 358.71 10.76 78.26 4.88 22.40 2 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 104 6.53 29.96 224.51 6.74 48.98 2.04 9.35 

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

MISC. BPD SCF/HR COUNTTANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Completion GAS FLARE 625000 24 4 0.37 44.63 37.69 242.81 0.02 

2019 YEAR TOTAL 32.14 147.83 1149.54 70.84 483.89 73.40 336.72 

EXEMPTION 

CALCULATION DISTANCE FROM LAND IN MILES 4495.50 4495.50 

135.0
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum Cor Green Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FJill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR ESTIM

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM SOx 

DRILLING PRIME MOVER>600hp diesel 21,532 1039.9956 24959.89 24 89 15.18 69.62 521.70 15.65 113.83 16.21 74.36 Ensco 8506 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 38 10.44 47.87 358.71 10.76 78.26 1.19 5.46 2 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 25 6.53 29.96 224.51 6.74 48.98 0.49 2.25 

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

MISC. BPD SCF/HR COUNTTANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Completion GAS FLARE 625000 24 1 0.37 44.63 37.69 242.81 0.00 

2020 YEAR TOTAL 32.14 147.83 1149.54 70.84 483.89 17.89 82.07 

EXEMPTION 

CALCULATION DISTANCE FROM LAND IN MILES 4495.50 4495.50 

135.0
SUMMARY

COMPANY AREA BLOCK LEASE PLATFORM WELLAnadarko Petrol Green Canyon #REF! #REF! GC903 "D & DD, E

Emitted Substance

Year

 PM SOx NOx VOC CO

2014 70.40 322.95 2419.91 72.60 527.98

2015 73.40 336.72 2525.11 77.50 562.12

2016 73.40 336.71 2524.04 76.59 556.29

2017 73.40 336.72 2525.11 77.50 562.12

2018 73.40 336.71 2524.04 76.59 556.29

2019 73.40 336.72 2525.11 77.50 562.12

2020 17.89 82.07 615.44 18.90 137.08

2021 0.00 0.00 0.00 0.00 0.00

2022 0.00 0.00 0.00 0.00 0.00

2023 0.00 0.00 0.00 0.00 0.00

Allowable 4495.50 4495.50 4495.50 4495.50 89474.94

Form MMS-138 (May 2001)Page 8 of 8
EXPLORATION PLAN (EP)

AIR QUALITY SCREENING CHECKLIST

O

OMB Approval Ex

COMPANY Anadarko Petroleum Corporation

AREA Green Canyon

BLOCK 859 & 903LEASE OCS-G 24194 & 24197

PLATFORMWELL GC903 "D & DD, E" and GC 859 "F, G, H, FF, GG, HH, I, II, J"COMPANY CONTACT Jill FowlerTELEPHONE NO. 832-636-1554REMARKS Drill and complete 10 wells, and conduct 2 topsets

Form MMS-138 (May 2001)Page 1 of 8
EMISSIONS FACTORS

Fuel Usage Conversion Factors Natural Gas Turbines Natural Gas Engines Diesel Recip. Engine R

SCF/hp-hr 9.524 SCF/hp-hr 7.143 GAL/hp-hr 0.0483 AP4

Equipment/Emission Factors units PM SOx NOx VOC CO RNG Turbines gms/hp-hr 0.00247 1.3 0.01 0.83 AP42 3NG 2-cycle lean gms/hp-hr 0.00185 10.9 0.43 1.5 AP4NG 4-cycle lean gms/hp-hr 0.00185 11.8 0.72 1.6 AP4NG 4-cycle rich gms/hp-hr 0.00185 10 0.14 8.6 AP4

Diesel Recip. < 600 hp. gms/hp-hr 1 1.468 14 1.12 3.03 AP4

Diesel Recip. > 600 hp. gms/hp-hr 0.32 1.468 11 0.33 2.4 AP4Diesel Boiler lbs/bbl 0.084 2.42 0.84 0.008 0.21 AP42 NG Heaters/Boilers/Burners lbs/mmscf 7.6 0.593 100 5.5 84 P42 1.4-NG Flares lbs/mmscf 0.593 71.4 60.3 388.5 AP4Liquid Flaring lbs/bbl 0.42 6.83 2 0.01 0.21 AP42 1Tank Vapors lbs/bbl 0.03 E&P Fugitives lbs/hr/comp. 0.0005 APGlycol Dehydrator Vent lbs/mmscf 6.6 LaGas Venting lbs/scf 0.0034

Sulfur Content Source Value Units

Fuel Gas 3.33 ppm

Diesel Fuel 0.4 % weight

Produced Gas( Flares) 3.33 ppm

Produced Oil (Liquid Flaring) 1 % weight

Form MMS-138 (May 2001)Page 2 of 8
EMISSIONS CALCULATIONS 1ST YEAR

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum CorporaGreen Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FF, Jill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

DRILLING PRIME MOVER>600hp diesel 33,732 1629.2556 39102.13 24 350 23.78 109.07 817.30 24.52 178.32 99.86 Discoverer Spirit PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 150 10.44 47.87 358.71 10.76 78.26 4.70 2 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 100 6.53 29.96 224.51 6.74 48.98 1.96 

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

MISC. BPD SCF/HR COUNTTANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 Completion GAS FLARE 625000 24 0 0.37 44.63 37.69 242.81 

2014 YEAR TOTAL 40.74 187.28 1445.14 79.70 548.38 106.51 

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4495.50 

135.0

Form MMS-138 (May 2001)Page 3 of 8
EMISSIONS CALCULATIONS 2ND YEAR

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum CorGreen Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FF, GJill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM S

DRILLING PRIME MOVER>600hp diesel 33,732 1629.2556 39102.13 24.00 365.00 23.78 109.07 817.30 24.52 178.32 104.14 47Discoverer Spirit PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0AUXILIARY EQUIP<600hp diesel 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6.00 156 10.44 47.87 358.71 10.76 78.26 4.88 22 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6.00 104 6.53 29.96 224.51 6.74 48.98 2.04 9

VESSELS>600hp diesel(tugs) 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

VESSELS>600hp diesel(crew) 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0VESSELS>600hp diesel(supply) 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0

MISC. BPD SCF/HR COUNTTANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

Completion GAS FLARE 625000 24 4 0.37 44.63 37.69 242.81 0

2015 YEAR TOTAL 40.74 187.28 1445.14 79.70 548.38 111.06 50

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4495.50 44

135.0

Form MMS-138 (May 2001)Page 4 of 8
EMISSIONS CALCULATIONS 3RD YEAR

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum CorGreen Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FF, GJill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM S

DRILLING PRIME MOVER>600hp diesel 33,732 1629.2556 39102.13 24 365 23.78 109.07 817.30 24.52 178.32 104.14 47Discoverer Spirit PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 156 10.44 47.87 358.71 10.76 78.26 4.88 22 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 104 6.53 29.96 224.51 6.74 48.98 2.04 9

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

MISC. BPD SCF/HR COUNT

TANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0

Completion GAS FLARE 625000 24 2 0.37 44.63 37.69 242.81 0

2016 YEAR TOTAL 40.74 187.28 1445.14 79.70 548.38 111.06 50

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4495.50 44

135.0

Form MMS-138 (May 2001)Page 5 of 8
EMISSIONS CALCULATIONS 4TH YEAR

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum CorpGreen Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FF, GG Jill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

DRILLING PRIME MOVER>600hp diesel 33,732 1629.2556 39102.13 24 365 23.78 109.07 817.30 24.52 178.32 104.14 Discoverer Spirit PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 156 10.44 47.87 358.71 10.76 78.26 4.88 2 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 104 6.53 29.96 224.51 6.74 48.98 2.04 

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 MISC. BPD SCF/HR COUNT

TANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

Completion GAS FLARE 625000 24 4 0.37 44.63 37.69 242.81 

2017 YEAR TOTAL 40.74 187.28 1445.14 79.70 548.38 111.06 

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4495.50 

135.0

Form MMS-138 (May 2001)Page 6 of 8
EMISSIONS CALCULATIONS 5TH YEAR

COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum CorpGreen Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FF, GG Jill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR 

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM 

DRILLING PRIME MOVER>600hp diesel 33,732 1629.2556 39102.13 24 365 23.78 109.07 817.30 24.52 178.32 104.14 Discoverer Spirit PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 156 10.44 47.87 358.71 10.76 78.26 4.88 2 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 104 6.53 29.96 224.51 6.74 48.98 2.04 

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 MISC. BPD SCF/HR COUNT

TANK- 0 0 0 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 

Completion GAS FLARE 625000 24 2 0.37 44.63 37.69 242.81 

2018 YEAR TOTAL 40.74 187.28 1445.14 79.70 548.38 111.06 

EXEMPTION 

CALCULATION

DISTANCE FROM LAND IN 

MILES 4495.50 

135.0

Form MMS-138 (May 2001)Page 7 of 8
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum Cor Green Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FJill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR ESTIMATED TONS

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM SOx NOx VOC CO

DRILLING PRIME MOVER>600hp diesel 33,732 1629.2556 39102.13 24 365 23.78 109.07 817.30 24.52 178.32 104.14 477.73 3579.75 107.39 781.04

Discoverer Spirit PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 156 10.44 47.87 358.71 10.76 78.26 4.88 22.40 167.88 5.04 36.63

2 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 104 6.53 29.96 224.51 6.74 48.98 2.04 9.35 70.05 2.10 15.28

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

 

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

 

MISC. BPD SCF/HR COUNT

TANK- 0 0 0 0.00 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Completion GAS FLARE 625000 24 4 0.37 44.63 37.69 242.81 0.02 2.14 1.81 11.66

2019 YEAR TOTAL 40.74 187.28 1445.14 79.70 548.38 111.06 509.50 3819.82 116.34 844.60

EXEMPTION 

CALCULATION DISTANCE FROM LAND IN MILES 4495.50 4495.50 4495.50 4495.50 89474.94

135.0
COMPANY AREA BLOCK LEASE PLATFORM WELL CONTACT PHONE REMARKS

Anadarko Petroleum Cor Green Canyon #REF! #REF! GC903 "D & DD, E" and GC 859 "F, G, H, FJill Fowler 832-636-1554 0

OPERATIONS EQUIPMENT RATING MAX. FUEL ACT. FUEL RUN TIME MAXIMUM POUNDS PER HOUR ESTIMATED TONS

Diesel Engines HP GAL/HR GAL/D

Nat. Gas Engines HP SCF/HR SCF/D

Burners MMBTU/HR SCF/HR SCF/D HR/D DAYS PM SOx NOx VOC CO PM SOx NOx VOC CO

DRILLING PRIME MOVER>600hp diesel 33,732 1629.2556 39102.13 24 89 23.78 109.07 817.30 24.52 178.32 25.39 116.49 872.87 26.19 190.44

Discoverer Spirit PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

PRIME MOVER>600hp diesel 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

BURNER diesel 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

AUXILIARY EQUIP<600hp diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

3 trips/week VESSELS>600hp diesel(crew) 14805 715.0815 17161.96 6 38 10.44 47.87 358.71 10.76 78.26 1.19 5.46 40.89 1.23 8.92

2 trips/week VESSELS>600hp diesel(supply) 9266 447.5478 10741.15 6 25 6.53 29.96 224.51 6.74 48.98 0.49 2.25 16.84 0.51 3.67

VESSELS>600hp diesel(tugs) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

 

FACILITY DERRICK BARGE diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

INSTALLATION MATERIAL TUG diesel 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

VESSELS>600hp diesel(crew) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

VESSELS>600hp diesel(supply) 0 0 0.00 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

 

MISC. BPD SCF/HR COUNT

TANK- 0 0 0 0.00 0.00 

Flowback After OIL BURN 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Completion GAS FLARE 625000 24 1 0.37 44.63 37.69 242.81 0.00 0.54 0.45 2.91

2020 YEAR TOTAL 40.74 187.28 1445.14 79.70 548.38 27.07 124.20 931.14 28.37 205.95

EXEMPTION 

CALCULATION DISTANCE FROM LAND IN MILES 4495.50 4495.50 4495.50 4495.50 89474.94

135.0
SUMMARY

COMPANY AREA BLOCK LEASE PLATFORM WELLAnadarko Petrol Green Canyon #REF! #REF! GC903 "D & DD, E

Emitted Substance

Year

 PM SOx NOx VOC CO

2014 106.51 488.63 3661.41 109.84 798.852015 111.06 509.50 3819.82 116.34 844.602016 111.06 509.50 3818.75 115.43 838.772017 111.06 509.50 3819.82 116.34 844.602018 111.06 509.50 3818.75 115.43 838.772019 111.06 509.50 3819.82 116.34 844.602020 27.07 124.20 931.14 28.37 205.952021 0.00 0.00 0.00 0.00 0.00

2022 0.00 0.00 0.00 0.00 0.00

2023 0.00 0.00 0.00 0.00 0.00

Allowable 4495.50 4495.50 4495.50 4495.50 89474.94

Form MMS-138 (May 2001)Page 8 of 8
 

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 September 25, 2013 for Anadarko Petroleum Corporation 

and its subsidiaries, Anadarko US Offshore Corporation 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) 

Houma, Louisiana 

Harvey, Louisiana 

Venice, Louisiana 

Lake Charles, Louisiana 

Galveston, Texas 

Fourchon, Louisiana 

Harvey, Louisiana 

Venice, Louisiana 

Cameron, Louisiana 

Galveston, Texas 

(iii) OSRO Information 

Anadarko maintains a contract with 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.cleangulfassoc.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 Corporation (MSRC) for 

spill response equipment. MSRC stages equipment 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 Helix Well Containment Group (HWCG), a combination of the 

Helix Fast Response System (HFRS) and the common equipment and services. This agreement 

allows access to subsea well containment and well shut-in equipment. 

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

provides access to containment response capabilities and includes subsea dispersant injection 

equipment. 
 

(iv) Worst-Case Scenario Determination 

Category Regional OSRP EP EP 

Type of Activity Exploratory Exploratory Exploratory 

Facility Location 

(area/block) GC 683 GC 859 GC 903 

Facility Designation GC 683 “G” GC 859 “J” GC 903 “E” 

Distance to Nearest 

Shoreline 120 miles 135 miles 135 miles 

 Storage Tanks (total) N/A N/A N/A 

 Flowlines (on facility) N/A N/A N/A 

 Pipelines N/A N/A N/A 

 Uncontrolled Blowout 410,000 bopd* 263,660 bopd 244,402 bopd 

Type of Oil(s) Oil Oil Oil 

API Gravity 28.9o 31.4o 31.4o

*The volume denoted in the Regional OSRP is higher than the NTL No. 2010-N06 (403,608 bopd) calculations approved 

under EP Plan Control No. S-7623. Anadarko elected to denote a higher volume in the Regional OSRP for planning 

purposes to demonstrate equipment response capabilities per previous discussions with Mr. Mike Tolbert. 

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

Supplemental EP does not supersede the worst-case scenario for Green Canyon Block 683 as 

previously filed in the Regional OSRP. 

Since Anadarko has the capability to respond to the worst-case spill scenario included in our 

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

worst-case scenario in our Regional OSRP last approved on September 25, 2013, 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 discharge, resulting from the activities proposed in our 

EP. 

(b) Worst-Case Discharge Volume Assumptions 

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

and requirements pursuant with NTL No. 2010-N06. The following information summarizes the 

WCD scenario and assumptions used for Green Canyon (GC) Blocks 859 & 903. Please note 

that EP location J is referred to as the GC 859 #3 well and location E is referred to as GC 903 #5 

in the following WCD summary: 

Discussions regarding geologic information are considered proprietary and have been omitted 

from this public copy of the EP. Note, some attachments have been not included due to 

proprietary information. 

(c) Oil Spill Response Discussion

For the purpose of NEPA analysis, the largest spill volume originating from the proposed 

activity would be an uncontrolled blowout of the well during drilling operations at 263,660 
 

BOPD with an API gravity of 31.4o. A discussion of the blowout scenario from this proposed 

activity is included within this Supplemental 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 Analysis 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 OCS Activities” (OCS Report MMS 2004-026), using the 

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

Green Canyon Blocks 859 & 903 are located within Launch Area 46. According to the BOEM 

OSRAM, the trajectory indicates a 3% probability of potential impact to the shoreline in 

Cameron and/or Plaquemines Parish, Louisiana. The results are shown in Table H-2. 

Cameron and/or Plaquemines Parish are identified as the most probable potential impacted parish 

or county within the Gulf of Mexico for this operation. Cameron Parish is located in Louisiana 

and includes Cameron Prairie National Wildlife Refuge (NWR), East Cove Unit (a part of the 

Cameron Prairie NWR), Lacassine NWR, and Sabine NWR. Plaquemines Parish is also located 

in Louisiana and includes Delta NWR, Pass-a-Loutre Wildlife Management Area (WMA), and 

Bohemia State 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 detection 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 of the well would be 

considered the largest potential spill volume at 263,660 BOPD. An ADIOS weathering model 

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

information, approximately 15% (39,549 bbls) of the initial volume would be 

evaporated/dispersed within 24 hours. 

If approved and appropriate, 4 sorties (8,000 gallons) from the Basler aircraft 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 during Deepwater Horizon, 

approximately 5% (13,183 bbls) of the total initial worst case discharge could be burned after 

natural evaporation/dispersion. 

Although unlikely in a spill lasting thirty (30) days, potential shoreline impact in Cameron and/or 

Plaquemines Parish, Louisiana could occur depending on environmental conditions (wind, 
 

currents and temperature) at the time of an incident. Nearshore response may include the use of 

shoreline boom on beach areas, or protection/sorbent boom on vegetated areas. Surveillance and 

real time trajectories would aide in determining the most appropriate strategies to respond to a 

spill. 

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

personnel to respond to a spill of 224,111 bbls, which is the estimated amount that would remain 

considering natural evaporation/dispersion at 24 hours. This amount could be further reduced 

through the application of aerial and subsea dispersants, and in-situ burning provided such 

applications/actions were approved. 

Anadarko’s contingency plan for dealing with this worst-case discharge would be to activate its 

Spill Management Team and equipment resources as described in its Gulf of Mexico Regional 

Oil Spill Response Plan (OSRP) and provide 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 incident is deemed complete or until released by 

Unified Command. 

Anadarko is a member of the Helix Well Containment Group (HWCG), a combination of the 

Helix Fast Response System (HFRS) and the common equipment and services. This agreement 

allows access to subsea well containment and well shut-in equipment. 

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

provides access to containment response capabilities and includes subsea dispersant injection 

equipment. 

In the event of a blowout, Anadarko may: 

 1. Evacuate personnel, if necessary. Deploy emergency 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 spilled and calculate additional potential of oil 

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

slick and the volume of oil on the water. Observations of the size of the slick on the 

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

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

dynamically positioned (DP) semi-submersible drilling rig would be determined by 

marine surveyors. Operations and Unified Command would continue to assess the 

adequacy of response 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 trajectories. If oil is seaward 

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

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

request approval to utilize dispersants. 

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

with natural resource specialists to determine if any threatened or endangered species 

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

application. 

 b. Upon approval, mobilize one Basler aircraft and two DC-3 aircrafts from Houma, with 

surveillance aircraft and spotter. Mobilize MSRC contracted aircraft(s) if needed. 

Rotate aircraft, spraying the leading edge of the spill and working back to the source. 

Monitor/sample for effectiveness (USCG SMART Team). Truck additional 

dispersants from CGA/MSRC stockpile to Houma, if necessary. 

 c. Dispersants are most effective when applied as soon after discharge as possible, since 

weathering of the oil decreases dispersant effectiveness. The estimated window of 

opportunity for most effective use of dispersants is within 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 the oil has been on the 

water for more than three days. Ultimately, 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 location 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 for long-duration, high-volume skimming. 

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

approximately 28 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 encounter 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 activated 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 vessels 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) would arrive on-scene between approximately 

14.8-23 hours of the initial release. These skimmers operate downstream of the HOSS 

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

large stationary skimmer. Each FRU has 200 barrels of on-board storage. Approval 

will be requested to decant water after gravity separation, through a hose forward of 

the skimmer, to optimize temporary storage capacity. A 42" Boom will be utilized to 

concentrate oil so that 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 only. 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, trajectories, 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 could be commenced again. Safety would 

remain the first priority. 

 10. Prepare Site-Specific Waste Management Plan, Site Safety Plan, Decontamination Plans, 

Communications and Medical Plans. 

 11. If oil becomes a threat to any shoreline, data from the aerial surveillance, weather reports, 

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

boom with reference to Area Contingency Plans 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 Removal Organization (OSRO) personnel to relieve equipment 

operators 

 Vessels for supporting offshore operations 

 Field safety personnel 

 Continued surveillance and monitoring of oil movement 

 Helicopter, video cameras 

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

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

storage barges to onshore disposal sites that 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 transported from Houston to Houma or other potential 

command post locations 

- Communications equipment and technicians 

 Logistics needed to support responder personnel 

- Medical aid stations 

- Safety personnel

- Food 

- Berthing 

- Additional clothing/safety supplies 

- Decontamination stations 

Louisiana CZM Containment Response Information 

Anadarko has the capability to respond and contain, to the maximum extent practicable as 

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

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

equipment is subject to availability and location, 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 details 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 during the Application for Permit to Drill (APD) 

process, including the Well Containment Screening 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 prevention, control, and/or cleanup. 
 

Table H-1 

Worst Case Discharge Calculation 

(Based on Blowout during Drilling Operations)

Calculations for Uncontrolled Blowout> 10 miles from shore: Blocks 859 & 903 

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

 ii. API Gravity 31.4o

 iii. EP Location Used for NTL No. 2010-N06 WCD for GC 859 & 903 SEP GC 859 well “J” 

 iv. Largest Anticipated WCD Rate during blowout 263,660 BOPD 

 v. WCD Total for Drilling Operations for GC 859 & 903 (> 10 miles from 

shore): 263,660 BOPD 
 

Table H-2 

Trajectory by Land Segment 

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

particular launch area will contact a land segment as included in the BOEMRE Oil Spill Risk Analysis Model 

(OSRAM) for the Central Gulf of Mexico. This information can be found on the BOEMRE website using 3/10/30 

day potential impact, as applicable. The results are listed below. 

Area/Block OCS-G Launch 

Area Land Segment and/or Resource 

Conditional Probability (%) 

3 

days 

10 

days 

30 

days 

Green Canyon 

Blocks 859 & 903 

Drilling 

(135 miles from 

shore) 

G24194 

& 24197 

LA 46 

Central 

Planning 

Area 

Matagorda County, TX 

Brazoria County, TX 

Galveston County, TX 

Jefferson County, TX 

Cameron Parish, LA 

Vermilion Parish, LA 

Lafourche Parish, LA 

Terrebonne Parish, LA 

Plaquemines Parish, LA 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

-- 

1 

1 

2 

1 

3 

1 

1 

1 

3 
Table H-3 

WCD Scenario Drilling Activities – Based on a single well uncontrolled blowout (135 miles from shore) Green Canyon Blocks 859 & 903 263,660 BOPD (initial volume) 224,111 BOPD (after evaporation/dispersion) API Gravity 31.4o

Offshore Equipment from Spill Detection to Equipment Deployment Response Time: Green Canyon Blocks 85

Spill Team Area Responders (STARS) called out by Marine Spill Response Corporation (MSRC) Vessel of Opportunity=VOO EMS=Enterprise Marine Services K-Sea=K-Sea Operating Partnership 


Nearshore Equipment from Spill Detection to Equipment Deployment Response Time: Green Canyon Blocks 8
*Some equipment may be used offshore up to approximately 25 miles from shore 
 

H-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 Environmental Mitigation Measures 

(a) Monitoring 

If required, Anadarko will monitor loop currents per NTL 2005-G05. 

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

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

(b) Incidental Takes 

Although marine mammals may be seen in the 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 the Marine Mammal Protection Act. 

Anadarko will operate in accordance with applicable regulations, including: 

NTL No. 2012-G02 – “Implementation of Seismic Survey Mitigation Measures and 

Protected Species Observer Program” 

BSEE NTL No. 2012-G01 “Marine Trash and Debris Awareness and Elimination”, and 

JOINT NTL No. 2012-G01 “Vessel Strike Avoidance and Injured/Dead Protected 

Species Reporting” 
 

J 

LEASE STIPULATIONS INFORMATION 

Lease Sale # 182: 

Military Area: Green Canyon Blocks 859 & 903 is located within Military Warning Area 

W-92. Anadarko will contact the Naval Air Station, Air Operations Department, New 

Orleans, Louisiana in order to coordinate and control the electromagnetic emissions 

during these proposed operations. 

Marine Protected Species: This stipulation is meant to reduce the potential taking of 

marine protected species. Anadarko will operate in accordance with JOINT NTL 2012-

G01 to minimize the risk of vessel strikes to protected species and will report 

observations of injured or dead protected species. Anadarko will operate in accordance 

with BSEE NTL 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 N/A N/A N/A 

(b) Diesel Oil Supply Vessels 

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

a. Size of fuel supply vessel: 230 feet 

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

c. Frequency that fuel supply vessel will visit the facilities: twice 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 128 

miles to GC 859 & 903.

(c) Vicinity Map 

A vicinity map is included in this section as Attachment K-1. 

(d) Produced Liquid Hydrocarbons Transportation Vessels 

Produced liquid hydrocarbons from future flow tests on wells in Green Canyon Blocks 859 & 903 will be 

transported by barge. Anadarko will also flare a max volume of 30MMSCF/well total during the 48 hour 

flow test period. Flow tests will not exceed 48 hours/well without further approval. 

Transport Method Vessel Capacity Average Volume to be Loaded 

(per transfer) 

No. of Transfers 

(Yearly Average) 

Barge 1/well 

(e) Summary of Method to Transfer Liquid Hydrocarbons to the Transporting Vessel 

Production from the wells will be routed through portable surface well test equipment and safety controls 

aboard the rig. Gas will be flared and liquids (oil & water) will be collected in US Coast Guard approved 

tanks and a barge. The wells will be produced / cleaned up and measured using various meters through 

portable surface well test equipment including a separator. A three phase separator will be used to analyze 

water cut if present. All liquids (hydrocarbons and water) will then be transferred to a coast guard 

approved barge via tested & approved petroleum transfer hose. We will have a Safe Breakaway Coupling 

(KLAW) installed between the hoses connecting the barge-end and the rig-end. If this device parts the 

KLAW is designed to contain all fluids from both hoses. 
 

(e) 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 

mud 

Syntheticbased drilling 

muds 

156,000 bbls 13,000 bbls/well Re-use 

and/or 

transport to 

shore in 

DOT 

approved 

containers. 

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 

3,900-7,800 

bbls

325-650 

bbls/well* 

*An estimated 

5-10% of cuttings 

may be 

transported to 

shore 

Re-use 

and/or 

transport to 

shore in 

DOT 

approved 

containers. 

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 

7,487 bbls 

** 

1,872 bbls** 

100 bbls/month 

25 bbls/month 

Transport to 

shore in 

DOT 

approved 

containers 

for pick up 

Chemwaste in Sulphur, 

LA and Veolia Port 

Arthur, TX or to Newpark, 

Port Arthur as nonhazardous 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 

30,000 

bbls** 

3,000 bbls/well Transport to 

shore in 

DOT 

approved 

containers 

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 

30,000 

bbls** 

3,000 bbls/well Transport to 

shore in 

DOT 

approved 

containers 

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. 
 

Trash and 

debris 

Refuse 

generated 

during 

operations 

3,777 bbls 50 

bbls/month/well 

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 

8,120 bbls 430 bbls/120 

days/well 

Transport in 

DOT 

approved 

containers to 

shore for 

pick up 

American Recovery 

Fourchon, LA 

Recycled 

*Total amount assumes 12 wells with 2,266 Total No. of Days 

**This type of waste will not exist for the proposed GC 859 “J” and GC 903 “E” locations since only top-hole 

drilling for these wells will occur under this plan. This type of waste will only occur for the additional 10 well 

locations proposed in GC 859 and 903 since these wells will be drilled to total depth and completed under this plan. 
Green Canyon Blocks 859 and 903 

Environmental Impact Analysis for Supplemental Exploration Plan 

Figure 1. Location of Green Canyon Blocks 859 and 903. 
 

L 

ONSHORE SUPPORT FACILITIES INFORMATION

(a) General 

Per NTL No. 2008-G04, the following tables reflect the onshore facilities Anadarko may utilize 

to provide supplies and service support for the activities proposed in this EP. 

Name Primary Location(s) Existing/New/Modified 

Anadarko Service Base Fourchon, Louisiana Existing 

Anadarko Service Base (Helicopter base) Houma, 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 base cannot be utilized Anadarko will exercise the use of an alternate 

service base during drilling and/or completion operations.

**Helicopter base only 

(b) Support Base 

No support base construction or expansion is planned for these activities. 

(c) 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 disposed 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 

mud 

Syntheticbased drilling 

muds 

156,000 bbls 13,000 bbls/well Re-use 

and/or 

transport to 

shore in 

DOT 

approved 

containers. 

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 

3,900-7,800 

bbls

325-650 

bbls/well* 

*An estimated 

5-10% of cuttings 

may be 

transported to 

shore 

Re-use 

and/or 

transport to 

shore in 

DOT 

approved 

containers. 

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 

7,487 bbls 

** 

1,872 bbls** 

100 bbls/month 

25 bbls/month 

Transport to 

shore in 

DOT 

approved 

containers 

for pick up 

Chemwaste in Sulphur, 

LA and Veolia Port 

Arthur, TX or to Newpark, 

Port Arthur as nonhazardous 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 

30,000 

bbls** 

3,000 bbls/well Transport to 

shore in 

DOT 

approved 

containers 

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 

30,000 

bbls** 

3,000 bbls/well Transport to 

shore in 

DOT 

approved 

containers 

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. 

Trash and 

debris 

Refuse 

generated 

during 

operations 

3,777 bbls 50 

bbls/month/well 

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 

8,120 bbls 430 bbls/120 

days/well 

Transport in 

DOT 

approved 

containers to 

shore for 

pick up 

American Recovery 

Fourchon, LA 

Recycled 

*Total amount assumes 12 wells with 2,266 Total No. of Days 

**This type of waste will not exist for the proposed GC 859 “J” and GC 903 “E” locations since only top-hole 

drilling for these wells will occur under this plan. This type of waste will only occur for the additional 10 well 

locations proposed in GC 859 and 903 since these wells will be drilled to total depth and completed under this plan. 
 

M 

COASTAL ZONE MANAGEMENT ACT INFORMATION 
 

TEXAS COASTAL MANAGEMENT PROGRAM 

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 areas. The proposed activities are explorative in 

nature, so no facility construction is proposed. The proposed activities are located approximately 

245 miles from the Texas shoreline; therefore we expect no adverse impacts to CNRAs or beach 

access and use rights of the public. All activities shall be conducted in a manner that minimizes 

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 impact 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, therefore, 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 an approved Regional Oil Spill Response Plan. The 

plan is in place, practiced, and updated as necessary. The best practical techniques shall be 

utilized to prevent the release of pollutants or toxic substances into the environment. All involved 

vessels and facilities are designed to be capable of prompt response and adequate removal of 

accidental discharges of oil. In addition, the proposed activities are 245 miles from shore; 

therefore no damages to natural resources are expected as the result of an unauthorized discharge 

of oil into coastal waters. 

(Category 6) 

Discharge of Municipal and Industrial Waste Water to Coastal Waters 

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

are 245 miles from shore; therefore there will be no effect on coastal waters. 
 

(Category 8) 

Development in Critical Areas 

None of the proposed activities will occur in a critical area; therefore no effects to Texas’ coastal 

zone are expected. The activity will not jeopardize the continued existence of species listed as 

endangered or threatened, and will not result in likelihood of the destruction or adverse 

modification of a habitat determined to be a critical habitat under the Endangered Species Act. 

The activity will not cause or contribute to violation of any applicable surface water quality 

standards. The 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 proposed activities are not expected to have any adverse impacts on 

submerged lands. 

(Category 10) 

Dredging and Dredged Material Disposal and Placement 

No dredging or disposal/placement of dredged material is proposed; therefore no adverse effects 

to coastal waters, submerged lands, critical areas, coastal shore areas, or Gulf beaches are 

expected. 

(Category 11) 

Construction in the Beach / Dune System 

The proposed activities do not include any construction projects in critical dune areas or areas 

adjacent to or on Gulf beaches, therefore, no impact to Texas’ beach or dune systems are 

expected. 

(Category 15) 

Alteration of Coastal Historic Areas 

The proposed activities do not include any alteration 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 transportation 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 applicable air quality laws, 

standards, and regulations. Emissions from the proposed activities are not expected to have 

significant impacts on onshore air quality because of the prevailing atmospheric conditions, 

emission heights, emission rates, and the distance of these emissions from the coastline. The 
 

proposed activities will occur approximately 245 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 impoundment or diversion of state water, therefore, no 

impacts to Texas’ coastal zone is expected. 

(Category 20) 

Marine Fishery Management 

The proposed activities are located approximately 245 miles from shore and are not expected to 

have any effect on marine fishery 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 conclusion, 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 

with other uses of the vicinity. 

 

MISSISSIPPI COASTAL ZONE MANAGEMENT ACT INFORMATION 

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

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

proposed Federal license and permit activities affecting any coastal use or resources, in or 

outside of the Mississippi 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 practical techniques for drilling locations, drilling 

equipment guidelines for the prevention of adverse environmental effects, effective 

environmental protection, emergency 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 Fourchon, Louisiana. The activities 

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

Mississippi coastal areas will be conserved for water dependent industry. 

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

where a specific alteration of specific coastal wetlands would serve a higher public 

interest in compliance with the public purposes of the public trust in which the 

coastal wetlands are held. 

Goal 2 is addressed in Section N, Environmental Impact Analysis. The nearest proposed 

activities will be 210 miles from the Mississippi coast. 

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

connection with the revitalization of the seafood industry of the State of Mississippi. 

Goal 3 is addressed in Section N, Environmental Impact Analysis. Little impact to the 

seafood industry can be expected due to the activities occurring 210 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, agricultural, industrial, recreational and other 

legitimate beneficial uses. 

Goal 4 is addressed in Section B, General Information, Section G, Air Emissions 

Information, and Section N, Environmental Impact Analysis. 
 

Goal 5: To put to beneficial use to the fullest 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 OCS will be conducted in accordance with our 

Regional Oil Spill Response Plan referenced 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 E, Biological, Physical and Socioeconomic Information, 

and Section N, Environmental Impact Analysis. 

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

Goal 7 is addressed in Section F, Waste Discharges Information, Section H, Oil Spill 

Information, Section G, Air Emissions Information, and Section N, Environmental 

Impact Analysis. 

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

manner consistent with the coastal program. 

As the proposed activities are located 210 miles from the Mississippi 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

Green Canyon Blocks 859 and 903 (OCS-G 24197)

Offshore Louisiana

October 2013

Prepared for:

Jill Fowler

Regulatory Analyst

Anadarko Petroleum Corporation

1201 Lake Robbins Drive 

The Woodlands, Texas 77380

Telephone: (832) 636-1554

Prepared by:

CSA Ocean Sciences Inc.

8502 SW Kansas Avenue

Stuart, Florida 34997

Telephone: (772) 219-3000
Green Canyon Blocks 859 and 903 October 2013 

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

A.3 Air Pollutant Emissions...................................................................................................................8

A.4 Effluent Discharges.........................................................................................................................8

A.5 Water Intake...................................................................................................................................8

A.6 Onshore Waste Disposal.................................................................................................................9

A.7 Marine Debris................................................................................................................................. 9

A.8 Support Vessel and Helicopter Traffic ............................................................................................9

A.9 Accidents ........................................................................................................................................9

A.9.1 Types of Accidents Evaluated .............................................................................................9

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............................................................................16

B. Affected Environment...........................................................................................17

C. Impact Analysis.....................................................................................................17

C.1 Physical/Chemical Environment...................................................................................................17

C.1.1 Air Quality .........................................................................................................................17

C.1.2 Water Quality....................................................................................................................20

C.2 Seafloor Habitats and Biota..........................................................................................................22

C.2.1 Soft Bottom Benthic Communities...................................................................................23

C.2.2 High-Density Deepwater Benthic Communities...............................................................25

C.2.3 Designated Topographic Features....................................................................................27

C.2.4 Pinnacle Trend Area Live Bottoms....................................................................................28

C.2.5 Eastern Gulf Live Bottoms................................................................................................. 28

C.3 Threatened, Endangered, and Protected Species and Critical Habitat........................................28

C.3.1 Sperm Whale (Endangered)..............................................................................................30

C.3.2 West Indian Manatee (Endangered).................................................................................34

C.3.3 Endangered Mysticete Whales.........................................................................................35

C.3.4 Non-Endangered Marine Mammals (Protected)..............................................................35

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)..............................................................................................45

C.3.9 Smalltooth Sawfish (Endangered).....................................................................................45

C.3.10 Beach Mice (Endangered)................................................................................................. 46

C.3.11 Elkhorn Coral (Endangered)..............................................................................................47
Contents

(Continued)

Page

Green Canyon Blocks 859 and 903 October 2013

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...............................................................................49

C.5 Fisheries Resources ......................................................................................................................51

C.5.1 Pelagic Communities and Ichthyoplankton ......................................................................51

C.5.2 Essential Fish Habitat........................................................................................................53

C.6 Archaeological Resources.............................................................................................................56

C.6.1 Shipwreck Sites.................................................................................................................56

C.6.2 Prehistoric Archaeological Sites........................................................................................57

C.7 Coastal Habitats and Protected Areas..........................................................................................58

C.8 Socioeconomic and Other Resources...........................................................................................62

C.8.1 Recreational and Commercial Fishing ..............................................................................62

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

F. Mitigation Measures.............................................................................................68

G. Consultation .........................................................................................................69

H. Preparers..............................................................................................................69

I. References.............................................................................................................69
Green Canyon Blocks 859 and 903 October 2013 

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 3 will contact a certain parish, county, or coastline within 120 days 

(Modified from: BOEM, 2012b, Appendix C)........................................................................13

4 Benthic community data from stations near the lease area and in similar water 

depths sampled during the Northern Gulf of Mexico Continental Slope Habitats 

and Benthic Ecology Study (Adapted from: Wei, 2006; Rowe and Kennicutt, 2009)...........23

5 Federally listed endangered and threatened species potentially occurring in the 

lease area and along the northern Gulf Coast......................................................................29

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

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

2012b)...................................................................................................................................59

List of Figures 

Figure Page

1 Location of Green Canyon Blocks 859 and 903 ......................................................................2

2 Bathymetric map of the lease area showing the surface hole locations of the 

proposed wellsites................................................................................................................18

3 Location of selected environmental features in relation to the lease area .........................43
Green Canyon Blocks 859 and 903 October 2013 

Environmental Impact Analysis for Supplemental Exploration Plan Page v 

Acronyms and Abbreviations

Anadarko Anadarko Petroleum Corporation

ADIOS2 Automated Data Inquiry for Oil Spills 2 

bbl barrel

BHL bottom hole location

BML below mud line

BOEM Bureau of Ocean Energy Management

BOEMRE Bureau of Ocean Energy Management, 

Regulation and Enforcement

BOP blowout preventer

B.P. Before Present 

BSEE Bureau of Safety and Environmental 

Enforcement

CFR Code of Federal Regulations

CH4 methane

CO carbon monoxide

CO2 carbon dioxide

CGA Clean Gulf Associates

DP dynamic positioning

EEZ Exclusive Economic Zone

EFH Essential Fish Habitat

EIA Environmental Impact Analysis

EIS Environmental Impact Statement

EP Exploration Plan

ESA Endangered Species Act

FAD fish-attracting device

FR Federal Register

Fugro Fugro Geoconsulting, Inc.

GC Green Canyon

GMFMC Gulf of Mexico Fishery Management 

Council

GPS global positioning system

H2S 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

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

NO2 nitrogen dioxide

NOx 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

OBM oil-based mud

OCS Outer Continental Shelf

OSAT Operational Scientific Advisory Team

OSRA Oil Spill Risk Analysis

OSRP Oil Spill Response Plan

PAH polycyclic aromatic hydrocarbon

PM particulate matter

PSD Prevention of Significant Deterioration

SBM synthetic-based mud

SHL surface hole location

SOx 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 discharge
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 1 

Introduction

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

for Green Canyon (GC) Blocks 859 (GC 859) and 903 (GC 903). The EP includes 10 exploratory 

well locations: GC 859-F, GC 859-G, GC 859-H, GC 859-I, GC 859-FF, GC 859-GG, GC 859-HH, 

GC 859-II, GC 903-D, and GC 903-DD. All surface hole locations (SHLs) and bottom hole locations 

(BHLs) will be located in GC 859 or GC 903. This Environmental Impact Analysis (EIA) provides 

information on the exploratory wells based on the SHLs.

Anadarko will also conduct top-hole drilling on two additional wells with SHLs in GC 903 (EP 

locations GC 859-J and GC 903-E). Waste discharges and air emissions associated with drilling 

these two wells to the final total depth, as well as completion operations, will be addressed in a 

future EP. The remaining drilling operations to total depth and completion operations will be 

conducted using a different drilling vessel to be discussed in the subsequent EP submittal. Only 

waste discharges and air emissions associated with the top-hole drilling of GC 859-J and GC 903-

E have been included in this plan.

The lease area is 135 miles (217 km) from the nearest shoreline, 144 miles (232 km) from the 

onshore support base at Port Fourchon, Louisiana, and 172 miles (277 km) from the helicopter 

base at Houma, Louisiana (Figure 1). Water depths at the wellsites range from 5,268 to 5,355 ft 

(1,606 to 1,632 m). The drilling rig is yet to be determined, but will be either a dynamic 

positioning (DP) drillship or a DP semisubmersible rig. Drilling is expected to commence in early 

2014 and be completed in mid 2020.

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

accordance with applicable regulations, including 30 Code of Federal Regulations 

(CFR) 550.212(o) and 550.227. The EIA is a project- and site-specific analysis of Anadarko’s 

planned activities under this EP. This EIA complies with guidance provided in existing Notices to 

Lessees and Operators (NTLs) issued by the former Minerals Management Service (MMS) and 

Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE), including 

NTL 2008-G04 and NTL 2013-G02. 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; BOEM, 2012a) and in multi-lease-sale EISs for the 

Western and Central Gulf of Mexico Planning Areas (MMS, 2007b; BOEM, 2012b). The analyses 

from these documents are incorporated here by reference.

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, 2012b).
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 2 

Figure 1. Location of Green Canyon Blocks 859 and 903. 
Green Canyon Blocks 859 and 903 October 2013 

Environmental Impact Analysis for Supplemental Exploration Plan Page 3 

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 the Bureau of 

Safety and Environmental Enforcement’s (BSEE’s) Final Drilling Safety Rule (75 Federal Register

[FR] 63365) issued following the Macondo incident, the baseline risk of a catastrophic blowout is 

estimated to be about once every 26 years.

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

Response Plan (OSRP) last approved on 17 April 2013 for Anadarko and its subsidiaries, 

Anadarko U.S. Offshore Corporation, and Anadarko E&P Company L.P. (Company Numbers 

00981, 02219, and 00148, respectively) in accordance with 30 CFR Part 254. The biennial 

update was submitted on 30 June 2013, and an amendment was submitted on 18 July 2013.

The OSRP details Anadarko’s plan to rapidly respond to 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 NTLs applicable to this EIA.

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

Analysis (EIA). 

NTL Title Summary

2013-G02 Extension of Prior Notices to 

Lessees

Extends the effective date of NTL 2008-G04 (and two other 

NTLs) until the end of the 2013 calendar year. 

2012-N06

Guidance to Owners and Operators 

of Offshore Facilities Seaward of 

the Coast Line Concerning Regional 

Oil Spill Response Plans 

Provides clarification, guidance, and information for 

preparation of regional Oil Spill Response Plans. 

Recommends description of response strategy for worst 

case discharge (WCD) scenarios to ensure capability to 

respond to oil discharges is both efficient and effective. 

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 guides be 

carried on all Gulf of Mexico petroleum vessels and that 

vessel operators and crews maintain a vigilant watch for 

marine mammals. Vessels are to slow down or stop to avoid 

striking protected species, and operators are required to 

report sightings of any injured or dead protected species.
Table 1. (Continued).

Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 4 

NTL Title Summary

2011-JOINT-G01

Revisions to the List of OCS Blocks 

Requiring Archaeological Resource 

Surveys and Reports

Provides new information of which Outer Continental Shelf

(OCS) blocks require archaeological surveys and reports and 

required survey 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 BOEM

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.

2009-G40 Deepwater Benthic Communities

Provides guidance for avoiding and protecting high-density 

deepwater benthic communities (including chemosynthetic 

and deepwater coral communities) from damage caused by 

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

Provides 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

Provides 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.
Green Canyon Blocks 859 and 903 October 2013 

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 BOEM-0142. 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)

The wells proposed in this EP will be drilled using either a DP drillship or a DP semisubmersible 

rig. DP drillships and DP semisubmersible rigs use a global positioning system (GPS), specific 

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

maintain position. Essentially, 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 any required station-keeping adjustment. This allows operations at sea where mooring 

or anchoring is not feasible.

The drilling rig for the wells proposed in this EP will be on site for an estimated total of 

2,266 days (ranging from 92 to 140 days per well for drilling and completion). Drilling the 

top-hole sections of GC 859-J and GC 903-E will take approximately 20 days total. 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 DP drillships and 

DP semisubmersible rigs 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.

A.2 Physical Disturbance to the Seafloor

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

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

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

generally about 0.25 ha (0.62 ac) (MMS, 2007a).
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 6 

Table 2. Matrix of impact-producing factors and affected environmental resources. X = potential impact; dash (--) = no impact or negligible impact.

Environmental Resources

Impact-producing Factors

Drilling Rig 

Presence (incl. 

noise & lights)

Physical 

Disturbance 

to Seafloor

Air 

Pollutant 

Emissions

Effluent 

Discharges

Water 

Intake

Onshore 

Waste 

Disposal

Marine 

Debris

Support 

Vessel/Helo 

Traffic

Accidents

Small Fuel 

Spill

Oil Spill 

(WCD)

Physical/Chemical Environment

Air quality and greenhouse gases -- -- --X(9) -- -- -- -- -- X(6) X(6)

Water quality -- -- -- X -- -- -- -- X(6) X(6)

Seafloor Habitats and Biota

Soft bottom benthic communities -- X -- X -- -- -- -- -- X(6)

High-density deepwater benthic communities -- --(4) -- --(4) -- -- -- -- -- X(6)

Designated topographic features -- --(1) -- --(1) -- -- -- -- -- --

Pinnacle trend area live bottoms -- --(2) -- --(2) -- -- -- -- -- --

Eastern Gulf live bottoms -- --(3) -- --(3) -- -- -- -- -- --

Threatened, Endangered, and Protected Species and Critical Habitat

Sperm whale (endangered) X(8) -- -- -- -- -- -- X(8) X(6,8) X(6,8)

West Indian manatee (endangered) -- -- -- -- -- -- -- X(8) -- X(6,8)

Endangered mysticete whales -- -- -- -- -- -- -- -- -- --

Non-endangered marine mammals (protected) X -- -- -- -- -- -- X X(6) X(6)

Sea turtles (endangered/threatened) X(8) -- -- -- -- -- -- X(8) X(6,8) X(6,8)

Piping Plover (threatened) -- -- -- -- -- -- -- -- -- X(6)

Whooping Crane (endangered) -- -- -- -- -- -- -- -- -- X(6)

Gulf sturgeon (threatened) -- -- -- -- -- -- -- -- -- X(6)

Smalltooth sawfish (endangered) -- -- -- -- -- -- -- -- -- X(6)

Beach mice (endangered) -- -- -- -- -- -- -- -- -- X(6)

Elkhorn coral (endangered) -- -- -- -- -- -- -- -- -- X(6)

Coastal and Marine Birds

Marine birds X -- -- -- -- -- -- X X(6) X(6)

Shorebirds and coastal nesting birds -- -- -- -- -- -- -- X -- X(6)

Fisheries Resources

Pelagic communities and ichthyoplankton X -- -- X X -- -- -- X(6) X(6)

Essential Fish Habitat X -- -- X X -- -- -- X(6) X(6)

Archaeological Resources

Shipwreck sites -- --(7) -- -- -- -- -- -- -- X(6)

Prehistoric archaeological sites -- --(7) -- -- -- -- -- -- -- X(6)

Coastal Habitats and Protected Areas

Beaches -- -- -- -- -- -- -- -- -- X(6)

Wetlands and seagrass beds -- -- -- -- -- -- -- -- -- X(6)

Coastal wildlife refuges and wilderness areas -- -- -- -- -- -- -- -- -- X(6)

Socioeconomic and Other Resources

Recreational and commercial fishing X -- -- -- -- -- -- -- X(6) X(6)

Public health and safety -- -- -- -- -- -- -- -- -- X(6)

Employment and infrastructure -- -- -- -- -- -- -- -- -- X(6)

Recreation and tourism -- -- -- -- -- -- -- -- -- X(6)

Land use -- -- -- -- -- -- -- -- -- X(6)

Other marine uses -- -- -- -- -- -- -- -- -- X(6)

WCD = worst case discharge.
Green Canyon Blocks 859 and 903 October 2013

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-mile zone of the Flower Garden Banks, or the 3-mile zone of Stetson Bank;

(b) 1,000-m, 1-mile, or 3-mile 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 any 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 400 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 H2S concentrations greater than 500 ppm might be encountered. 

• Green Canyon Blocks 859 and 903 were classified as H2S absent under the Initial Exploration Plan.

(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 archaeology 

survey blocks (BOEM, 2012c) 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. The site clearance 

surveys detected no man-made features within 610 m (2,000 ft) of any of the proposed wellsites. A

dynamic positioning (DP) drillship or DP semisubmersible rig will be used; therefore, seafloor 

disturbances due to anchoring will not occur.

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

or sea turtles or their critical habitats. 

• Impact-producing factors (IPFs) that may affect marine mammals, sea turtles, or their critical habitats 

include drilling rig presence, 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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 8 

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 drilling rig operations, 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 (SOx), nitrogen oxides (NOx), 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 lease area’s distance from 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 EP Section F. All offshore discharges will be in 

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

General Permit No. GMG290000 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 Port Fourchon, Louisiana, for recycling and/or 

disposal at 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 freshwater and seawater, and ballast water.

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. GMG290000 does 

not specify requirements for existing facilities (those that started construction before 

16 July 2006). The drilling vessel ultimately selected for this project will be in compliance with 

all cooling water intake structure requirements.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 9 

A.6 Onshore Waste Disposal

Wastes generated during drilling are tabulated in EP Section F. A total of approximately

3,777 bbl of trash will be generated 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 wastes 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 will use existing shorebase facilities at Port Fourchon, Louisiana, for onshore support 

for vessel activities. Air transportation (helicopters) will be based at facilities in Houma, Louisiana. 

No terminal expansion or construction is planned at either location. 

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 an estimated 10 round trips per week between the drilling vessel 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 

and 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. Additional guidelines and regulations specify that helicopters maintain an 

altitude of 305 m (1,000 ft) within 91 m (300 ft) of marine mammals (BOEM, 2012d).

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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 10 

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) and BOEM (2012b) analyzed 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 (2012a), 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, 2012b). 

The median size for spills <1 bbl is 0.024 bbl, and the median size for spills of 1 to 10 bbl is 3 bbl 

(BOEM, 2012a). 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, 2012b). 

The water-soluble fractions of diesel are dominated by two- and three-ringed polycyclic 

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

2003a). 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, 2003a) 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).

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 sea 

surface area 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 135 miles (217 km) from the nearest shoreline. Modeling results discussed

below indicate that a spill in the lease area would have a 4% or less probability of reaching the 

coastal areas of Louisiana 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. Slicks from spills are expected to persist for relatively 

short periods of time ranging from minutes (<1 bbl) to hours (<10 bbl) to a few days (10 to 

1,000 bbl) and rapidly spread out, evaporate and disperse into the water column
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 11 

(BOEM, 2012b). Because of the distance of these potential spills on the OCS and their lack of 

persistence, it is unlikely that a spill would make landfall prior to dissipation (BOEM, 2012b).

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. 

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

A.9.3 Crude Oil Spill (Worst Case Discharge)

Spill Size. Anadarko prepared this blowout scenario pursuant to guidance provided in 

NTL 2010-N06. GC 859-J is addressed in this blowout scenario since it is the location with the 

highest potential WCD rate for Green Canyon Blocks 859 and 903. A similar approach would be 

taken in the event of a blowout for the other wellsites in GC 859 and 903. Based on 

NTL 2010-N06 guidance, the maximum hydrocarbon discharge for GC 859 and 903 is calculated 

to be 263,660 bbl of oil per day. 

Time taken to mobilize a rig and drill a relief well. An estimated 7 to 21 days is required to 

suspend operations on a deepwater Gulf of Mexico well and begin drilling the relief well. This 

assumes 0 to 14 days to suspend current operations on an existing well and 7 days to mobilize 

and be ready to spud the relief well. The estimated time to drill the relief well is 100 days, 

which includes 20 days for additional directional work, for a total estimated time of 107 to 

121 days from time of blowout to finishing the relief well. The drilling days were based on the

proposed days to drill GC 859-J through the objective sands (interval of WCD), with additional 

time added for ranging.

The maximum total volume during a blowout could potentially be 31,902,860 bbl assuming 

121 days for the maximum duration of a blowout, multiplied by the worst case daily 

uncontrolled blowout volume of 263,660 bbl. The detailed analysis of this calculation can be 

found in EP 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 Macondo event; however, 

significant changes to the spill rates for the entire OCS are not anticipated (BOEMRE, 2011a; 

BOEM, 2012d). As noted in the Introduction, the baseline risk of a catastrophic blowout is 

estimated to be once every 26 years (BSEE Final Drilling Safety Rule, 75 FR 63365).

Included in EP 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 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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 12 

predict spill fate. Although this model has received some criticism (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 did it predict the fate 

of a release continuing 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 

BOEM 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 Western and 

Central Gulf of Mexico Planning Area Supplemental EISs (BOEMRE, 2011a; BOEM, 2012b) 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 3, the launch point nearest to the 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 on 

a daily basis to help position equipment and human resources throughout the duration of any 

major spill or uncontrolled release. 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 13 

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

Launch Point 3 will contact a certain parish, county, or coastline within 120 days

(Modified from: BOEM, 2012b, Appendix C).

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, State Percent Chance

Cameron, TX -- -- -- 2 -- -- -- -- -- -- -- 2 -- -- -- 2 

Willacy, TX -- -- -- 3 -- -- -- -- -- -- -- 2 -- -- -- 3 

Kenedy, TX -- -- -- 8 -- -- -- 1 -- -- -- 9 -- -- -- 5 

Kleberg, TX -- -- 1 6 -- -- -- -- -- -- -- 4 -- -- 1 6 

Nueces, TX -- -- 1 6 -- -- -- -- -- -- -- 2 -- -- 1 2 

Aransas, TX -- -- -- 5 -- -- -- 1 -- -- -- 3 -- -- -- 2 

Calhoun, TX -- -- 1 6 -- -- -- -- -- -- -- 6 -- -- 1 4 

Matagorda, TX -- -- 2 17 -- -- 3 4 -- -- -- 11 -- -- 1 6 

Brazoria, TX -- -- 3 12 -- -- 1 3 -- -- 2 8 -- -- 1 5 

Galveston, TX -- -- 3 10 -- -- 3 6 -- -- 2 5 -- -- 1 4 

Jefferson, TX -- -- 1 4 -- -- 7 9 -- -- 1 1 -- -- -- 2 

Cameron, TX -- -- 1 4 -- -- 11 12 -- 1 1 4 -- -- -- 4 

Vermilion, LA -- -- 1 2 -- -- 5 6 -- 1 1 2 -- -- -- --

Iberia, LA -- -- -- 1 -- -- 4 4 -- -- -- -- -- -- -- --

Terrebonne, LA -- 1 2 3 -- 4 12 14 -- -- -- 2 -- -- -- --

Lafourche, LA -- -- 1 1 -- 2 8 10 -- -- 1 2 -- -- -- --

Jefferson, LA -- -- -- 1 -- -- 2 2 -- -- 1 1 -- -- -- --

Plaquemines, LA -- -- -- 1 -- 2 10 12 -- -- 1 2 -- -- -- --

Jackson, MS -- -- -- -- -- -- 1 1 -- -- -- -- -- -- -- --

Baldwin, AL -- -- -- -- -- -- 1 1 -- -- -- -- -- -- -- --

Bay, FL -- -- -- -- -- -- -- 1 -- -- -- -- -- -- -- --

Franklin, FL -- -- -- 1 -- -- -- -- -- -- -- -- -- -- -- --

Monroe, FL -- -- -- -- -- -- -- -- -- -- -- 1 -- -- -- 1 

Miami-Dade, FL -- -- -- -- -- -- -- -- -- -- -- 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, 2003a).

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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 14 

Spill Response. BOEM has 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 (2012b) guidance is provided below.

NTL 2012-N06 – Guidance to Owners and Operators of Offshore Facilities Seaward of the 

Coast Line Concerning Regional Oil Spill Response Plans: This NTL, effective 10 August 2012, 

provides clarification, guidance, and information on the preparation and submittal of 

regional OSRPs for owners and operators of oil handling, storage, or transportation facilities, 

inclusive of pipelines, located seaward of the coastline. It states that lessees, designated 

operators, and pipeline right-of-way holders are responsible for preparation and submission 

of these plans. Some of the clarifications and recommended practices in the NTL are based 

on lessons learned from the Macondo oil spill response.

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 BOEMRE will evaluate whether 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 BOEMRE 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, to reduce the likelihood of a blowout, and to conduct effective and early 

intervention in the event of a blowout, including the arrangements for drilling relief wells 

and any other measures proposed. The early intervention methods of the third 

requirement could actually 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’s Regional OSRP was last approved on 17 April 2013. The biennial update was 

submitted on 30 June 2013, and an amendment was submitted on 18 July 2013. The OSRP 

provides a detailed plan for Anadarko to rapidly respond to and effectively manage oil spills that 

may result from drilling and production operations. The OSRP contains detailed information on 

“Quick Response” procedures, including:
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 15 

• 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 built 

into the hulls, below-deck storage, and marine electronics packages that include marine, aircraft 

and company-frequency radios; radar; moving map plotters; GPS; satellite phones; and depth 

finders. 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 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 their website at

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. MSRC equipment in the Gulf of 

Mexico includes seven oil spill response vessels, two fast-response vessels, five oil spill response 

barges, five platform supply vessels, 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 a particular focus on deepwater. The expansion is known as “Deep Blue.” Additional MSRC 

capabilities and a complete equipment listing are available on their website at

http://www.msrc.org/. 

Anadarko is also 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

(and 120 million standard cubic feet per day of gas) with potential for expansion.

See EP Section H for a detailed description of Anadarko’s site-specific response to the WCD for 

this plan.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 16 

A.9.4 Other Accidents Not Analyzed in Detail

BOEM (2012b) 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 (H2S) release. There are no other site-specific issues for the 

drilling of the wells proposed in this EP.

Chemical Spills. Chemicals are stored and used to condition drillling 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, 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, 2012b). 

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 fluids 

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 (>2,380 bbl) quantities of drilling fluids. Riser disconnect 

accidents are of particular concern when SBMs are in use (BOEMRE, 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 lease area, 

spilling 1,500 bbl. Diesel fuel is the product most frequently spilled, but oil, natural gas, 

corrosion inhibitor, hydraulic fluid, and lube oil have also been released as the result of vessel 

collisions. Human error accounted for approximately half of all reported vessel collisions from 

2006 to 2009. As summarized in MMS (2007b) and BOEM (2012b), 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 the NTL 2010-06 package 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 17 

submitted with the exploration plan, as required. The potential for a loss-of-well-control event 

will be minimized by adhering to the requirements of applicable regulations such as the Final 

Drilling Safety Rule and NTL 2010-N10, which specify additional safety measures for 

OCS activities.

H2S Release. GC 859 and GC 903 were classified as H2S absent under the Initial EP.

B. Affected Environment

Based on the site clearance survey conducted by Fugro Geoconsulting, Inc. (Fugro), water 

depths at the wellsites are anticipated to range from 1,606 to 1,632 m (5,268 to 5,355 ft) 

(Figure 2). The seafloor at the proposed wellsites is smooth, featureless, and appears stable. 

The wellbore at GC 903-D will intersect a fault at 935 ft (285 m) below mud line (BML); GC 903-E 

will intersect a fault at 990 ft (302 m) BML; and GC 859-J will intersect a fault at 938 ft (286 m) 

BML. None of the other wellbores at the proposed wellsites will penetrate subsea faults. There 

is no evidence of fluid expulsion features, or high-density deepwater benthic communities near 

the wellsites (Fugro, 2013). A detailed description of the regional affected environment, 

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 is provided in MMS (2007b) and BOEM 

(2012b). 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. 

C. Impact Analysis

This section analyzes the potential direct and indirect impacts of routine activities and accidents. 

Impacts have been analyzed extensively in multi-lease-sale EISs for the Western and Central Gulf 

of Mexico Planning Areas (MMS, 2007b; BOEM, 2012b). 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). 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 18 

Figure 2. Bathymetric map of the lease area showing the surface hole locations of the proposed wellsites.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 19 

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 

BOEMRE (2011a) and BOEM (2012b).

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 and 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, SOx, NOx, 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, 

emission rates and heights, and resulting pollutant concentrations. The incremental 

contribution to cumulative impacts from activities similar to Anadarko’s proposed activities 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 (NO2). 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 area from shore, emissions from the activities described in 

Anadarko’s proposed EP are not likely to contribute to violations of any NAAQS onshore.

Carbon dioxide (CO2) and methane (CH4) 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 CO2 emissions from all OCS activities in the 

2007-2012 leasing program are about 0.08% to 0.016% of the global CO2 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 MMS (2007a,b). Because of 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 MMS (2007b), emissions 

of air pollutants from routine activities in the Central and Western 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. 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 20 

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. BOEM is required to notify the National Park Service (NPS) and the 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 189 miles (304 km) from the Breton 

Wilderness Area, and no air quality impacts on the Wilderness Area are expected. Anadarko will 

comply with all BOEM requirements regarding air emissions.

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 MMS (2007b) and BOEM (2012b,d). 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 could reduce the

potential impacts. EP Section H includes a 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 sea surface area 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 MMS (2007b) and BOEM (2012b,d).

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 NOx, SOx, 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’s distance from the nearest shoreline, most air quality impacts would 

occur in offshore waters with minimal chances 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 MMS (2007b), deepwater areas in the northern Gulf of Mexico are relatively 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 21 

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 185 miles (298 km) from the Macondo spill site. Based 

on the general circulation pattern seen in the Gulf of Mexico and satellite imagery, the surface 

slick from that discharge did not extend over the lease area during the spill, and it is unlikely 

that water quality in the lease area was affected.

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 

Port Fourchon, Louisiana, 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 MMS (2007b) and BOEM (2012a,b). 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 could 

potentially help mitigate and reduce the impacts. EP 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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 22 

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). 

The sea surface area 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, 2003a). The constituents of these oils are light 

to intermediate in molecular weight and can be readily degraded by aerobic microbial oxidation. 

Because the density of diesel is less than the density of seawater, diesel will not sink and pool on 

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, 2003a) 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 MMS (2007b) and BOEM (2012b,d). 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 sediments and be removed from the water column (Operational Scientific Advisory 

Team [OSAT], 2010).

Because of the lease area’s distance to the nearest shoreline, 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 project area range from 1,606 to 1,632 m (5,268 to 5,355 ft). The

seafloor at the proposed wellsites is smooth, featureless, and appears stable. One fault 

intersects the proposed GC 903-D wellbore at 935 ft BML. Several seafloor scarps are present

from 500 to 1,000 ft southwest of the GC 903-D wellsite, but the scarps dip away from the 

wellsite and will not be intersected by the wellbore (Fugro, 2013). 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 23 

Based on the absence of hard bottom areas detected by side-scan sonar during the site 

clearance survey, the seafloor within 610 m (2,000 ft) of the wellsites 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 within 

610 m (2,000 ft) of the wellsites, and the presence of chemosynthetic communities is considered 

negligible (Fugro, 2013).

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 collected at stations in water depths similar to the proposed drilling 

area.

Table 4. Benthic community data from stations near the lease area and in similar water depths 

sampled during the Northern Gulf of Mexico Continental Slope Habitats and Benthic 

Ecology Study (Adapted from: Wei, 2006; Rowe and Kennicutt, 2009).

Station Water Depth

(m)

Abundance

Meiofauna

(individuals/m2)

Macroinfauna

(individuals/m2)

Megafauna

(individuals/ha)

NB3 1,875 165,245 1,342 191

NB5 2,065 117,263 706 1,600

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 (1,606 to 1,632 m) typically range from 

approximately 190,000 to 343,000 individuals/m2 (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 2,062 individuals/m2

. 

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 3W, which includes the most complex bathymetric 

features in the northern Gulf of Mexico, including the Alaminos Canyon and the base of the 

Sigsbee Escarpment (Wei, 2006). The most abundant species in Zone 3W were the polychaetes 

Levinsenia uncinata, Paraonell monilaris, and Tachytrypane sp. A; the bivalve Heterodonta sp. B; 

and the isopod Macrostylis 256.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 24 

Megafaunal densities from nearby stations ranged from 0 to 1,600 individuals/ha. 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/m2 in the top 15 cm (6 in.) of sediments (Rowe and Kennicutt, 2009).

IPFs potentially affecting benthic communities are physical disturbance to the seafloor, effluent 

discharges (drilling muds and cuttings), and a large oil spill (WCD) resulting 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.

Physical Disturbance to the Seafloor

In water depths such as those encountered in the lease area, the areal extent of seafloor 

impacts will be small compared to the lease area itself. These types of soft bottom communities 

are ubiquitous along the northern Gulf of Mexico continental slope (Gallaway, 1988; Gallaway 

et al., 2003; Rowe and Kennicutt, 2009) and impacts from the physical disturbance of the 

seafloor during this project should 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 waterbased 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 wellsites. 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 H2S predominate (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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 25 

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 the wellsites 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 should 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 wellsites. 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).

Discussions in 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, 2003a).

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 approximately 38 miles (61 km) north of 

the lease area in GC 287. The nearest identified deep water coral communities are in GC 866, 

21 miles (34 km) east of the lease area. 

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 proposed drilling mud/cuttings 

discharge locations (Fugro, 2013).
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 26 

IPFs potentially affecting high-density deepwater benthic communities include physical 

disturbance 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 fuel would float and dissipate on the sea surface.

Physical Disturbance to the Seafloor

In water depths such as are encountered in the lease area, DP drillships or DP semisubmersibles 

disturb the seafloor only around the wellbore (SHL) where the bottom template and BOP are 

located. Depending upon the specific well configuration, this area is generally about 0.25 ha 

(0.62 ac).

The areal extent of these impacts from the DP drilling vessel 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. Based on the Fugro (2013) report, there should be no impacts on chemosynthetic or 

deepwater coral communities from this project.

Impacts of Effluent Discharges

The site clearance survey (Fugro, 2013) 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 

negligible. 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-m 

(984-ft) radius estimated by MMS (2007a, 2008), depending on its extent, trajectory, and 

persistence. Oil plumes that contact sensitive benthic communities before degrading could 

potentially impact the resource (BOEM, 2012b). 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. 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 27 

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 the 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 deep water 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) (BOEM, 2012d). 

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 Gulf of Mexico 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).

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 Ship Shoal South, in 

Ewing Bank Block 945, 63 miles (101 km) north of the lease area. 

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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 28 

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 in Main Pass Block 290, 205 miles (330 km) 

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 Eastern Gulf Live Bottoms

The lease area is not covered by the Live Bottom (Low-Relief) Stipulation, which pertains to 

seagrass communities and low-relief hard-bottom reef within the Eastern Gulf of Mexico

Planning Area blocks in water depths of 100 m (328 ft) or less and portions of Pensacola and 

Destin Dome Area blocks in the Central Gulf of Mexico Planning Area. The nearest block

covered by the live bottom stipulation, as defined by NTL 2009-G39, is Destin Dome Block 573, 

244 miles (393 km) northeast of the lease area.

There are no IPFs associated with either routine operations or accidents that could cause 

impacts to eastern Gulf 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). 

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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 29 

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

Sei whale Balaenoptera borealis E Xa -- None

Blue whale Balaenoptera musculus E Xa -- None

Fin whale Balaenoptera physalus E Xa -- None

North Atlantic right whale Eubalaena glacialis E Xa -- None

Humpback whale Megaptera novaeangliae E Xa -- None

Sperm whale Physeter macrocephalus E X -- None

West Indian manatee Trichechus manatus 

latirostris E -- X Florida (Peninsular)

Sea Turtles

Loggerhead turtle Caretta caretta T X X None

Green turtle Chelonia mydas T, Eb X X None

Leatherback turtle Dermochelys coriacea E X X None

Hawksbill turtle Eretmochelys imbricata E X X None

Kemp’s ridley turtle Lepidochelys kempii 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 Acropora palmata E -- 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.

As mandated by the ESA, MMS 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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 30 

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 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, 2012b). The existing consultation recognizes that BOEM-required mitigations and other 

reasonable and prudent measures should reduce the likelihood of impacts from all 

BOEM-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) discussed in MMS (2007b) and BOEM 

(2012b) are no longer federally listed as endangered or threatened. These are discussed in 

Section C.4.2, Shorebirds and Coastal Nesting Birds. 

There are five sea turtle and six marine mammal species that are currently listed as endangered 

and threatened by the ESA and known to occur within OCS and slope waters of the Gulf of 

Mexico. The listed sea turtles include the leatherback turtle, Kemp’s ridley turtle, hawksbill

turtle, loggerhead turtle, and green turtle. Listed marine mammal species include one 

odontocete (toothed) whale (sperm whale) and five mysticete (baleen) whales (blue whale, 

fin whale, humpback whale, North Atlantic right whale, and sei whale)(Pritchard, 1997; Würsig 

et al., 2000). No critical habitat has been designated for these species in the Gulf of Mexico.

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 MMS (2007b). Gulf of Mexico sperm 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 31 

whales are classified as an endangered species and a “strategic stock” (defined as a stock that 

may have unsustainable human-caused impacts) by NOAA Fisheries (Waring et al., 2012). 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, 2012b). 

Impacts of Drilling Rig Presence, Noise, and Lights

Noise generated from the drilling rig and from routine drilling activities may be audible to sperm 

whales and so has the potential to disturb individuals near the lease area. The drilling rig used 

during the proposed activity will be located within a deepwater, open ocean environment and 

will remain stationary during drilling operations. Sounds generated by the rig and by drilling 

operations will be generally continuous (with some variability in sound level, considering 

thruster activity). This analysis assumes that the continuous nature of sounds produced by the 

drilling rig will provide individual whales with cues relative to the direction and relative distance 

(sound intensity) of the sound source, and the fixed position of the drilling rig will provide 

multiple options for active avoidance of potential physical impacts. 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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 32 

sound source levels and concluded that drilling is not expected to produce amplitudes sufficient 

to cause hearing or behavioral effects in sperm whales; therefore, these effects are insignificant 

(NMFS, 2007).

In addition, 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. Drilling-related noise associated with this 

project will contribute to increases in the ambient noise environment of the Gulf of Mexico, but 

it is not expected in amplitudes sufficient to cause either hearing or behavioral effects to sperm 

whales.

Drilling rig lighting and rig presence are not identified as IPFs for sperm whales (MMS, 2007b; 

BOEM, 2012a,b,d; NMFS, 2007). 

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 MMS (2007b). To reduce the 

potential for vessel strikes, the 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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 33 

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 animal. Although responses are possible (Smultea 

et al., 2008), the NMFS (2007) and BOEM (2012d) concluded that this altitude would minimize 

the potential for disturbing sperm whales. Therefore, no significant impacts are expected. 

Impacts of a Small Fuel Spill

Potential spill impacts on marine mammals including sperm whales are discussed in MMS 

(2007b), BOEM (2012a,b,d), and NMFS (2007). Oil impacts on marine mammals are discussed 

by Geraci and St. Aubin (1990). For this EP, 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 could 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 sea surface area 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 MMS 

(2007b), BOEM (2012a,b,d), and NMFS (2007). For this EP, 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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 34 

migration (MMC, 2011). Ackleh et al. (2012) hypothesized that sperm whales may have 

temporarily relocated away from areas near the Macondo spill in 2010.

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 by 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 due to the 

distance to the nearest shoreline. 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 this NTL 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. In addition, 

guidelines and regulations specify that helicopters maintain an altitude of 305 m (1,000 ft) 

within 91 m (300 ft) of marine mammals (BOEM, 2012a,d). 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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 35 

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).

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.

Because of 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 whale 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 MMS (2007b) and BOEM (2012a,b,d), 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, including 2 species of 

mysticete whales, 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 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 and 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 36 

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.

Bottlenose dolphins. The bottlenose dolphin (Tursiops truncatus) is a common inhabitant of the 

northern Gulf of Mexico, particularly within continental shelf waters. There are two ecotypes of 

bottlenose dolphins, a coastal form and an offshore form, which are genetically isolated from 

each other (Waring et al., 2012). The offshore form of the bottlenose dolphin may occur within 

the lease area. Inshore populations of coastal bottlenose dolphins in the northern Gulf of 

Mexico are separated into 37 geographically distinct population units, or stocks, for 

management purposes by the NMFS (Waring et al., 2012). NMFS (2013) has proposed to classify 

the Gulf of Mexico Northern Coastal Stock, Western Coastal Stock, and all 32 of the Bay, Sound, 

and Estuarine Stocks as strategic stocks. A “strategic” stock is defined by the MMPA as a marine 

mammal stock

• for which the level of direct human-caused mortality exceeds the potential biological 

removal level;

• which, based on the best available scientific information, is declining and is likely to be listed 

as a threatened species under the ESA within the foreseeable future; or

• which is listed as a threatened or endangered species under the ESA, or is designated as 

depleted under the MMPA.

The strategic stock designation in this case was based primarily on the occurrence of an 

“unusual mortality event” of unprecedented size and duration that has affected these stock 

areas. This unusual mortality event began in February 2010 and is ongoing. Carmichael et al. 

(2012) hypothesized that the unusual number of bottlenose dolphin strandings in the northern 

Gulf of Mexico during this time may have been associated with environmental perturbations 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 37 

including sustained cold weather and the Macondo spill in 2010 as well as large volumes of cold 

freshwater discharge in the early months of 2011.

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 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.

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 generated during drilling operations is 

generally continuous and fixed in location. Noise intensity associated with these operations is 

relatively weak. Stronger noise levels will occur during thruster use in dynamic positioning. 

Thruster noise impacts would be expected at greater distances than vessel noise alone 

(LGL Ecological Research Associates, Ltd., 2006), but are dependent on variables relating to 

thruster type and usage. It is expected that marine mammals within or near the lease area 

would be able to detect the presence of the drilling rig and avoid exposure to higher energy 

sounds, particularly within an open ocean environment. Some odontocetes have shown 

increased feeding activity around lighted platforms at night (Todd et al., 2009). Even temporary 

drilling rigs present an attraction to pelagic food sources that may attract both cetaceans and 

sea turtles. Therefore, prey congregation could pose an attraction to protected species that 

exposes them to higher levels or longer durations of noise that might otherwise be avoided. 

There are other OCS facilities and activities near the lease area, and the region as a whole has a 

large number of similar sources. Species in the northern Gulf of Mexico have been exposed to 

noise from anthropogenic sources for a long period of time and over large geographic areas and 

likely do not represent a naïve population with regard to sound (National Research Council, 

2003b). This project would represent a temporary contribution to the overall noise regime

within the lease area, and potential impacts are expected to be biologically insignificant to 

marine mammal populations.

Drilling rig lighting and rig presence are not identified as IPFs for marine mammals (MMS, 

2007b, 2008; BOEMRE, 2011a; BOEM, 2012a,b).

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 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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 38 

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. In addition, guidelines and regulations specify that helicopters maintain 

an altitude of 305 m (1,000 ft) within 91 m (300 ft) of marine mammals (BOEM, 2012a,d). 

Maintaining this altitude will minimize the potential for disturbing marine mammals, and no 

significant impacts are expected (BOEM, 2012a,d).

Impacts of a Small Fuel Spill

Potential spill impacts on marine mammals are discussed in MMS (2007b) and BOEM (2012a,b); 

oil impacts on marine mammals in general are discussed by Geraci and St. Aubin (1990). For this 

EP, 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. EP 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 sea surface area 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.

Impacts of a Large Oil Spill (WCD)

Potential spill impacts on marine mammals are discussed in MMS (2007b) and BOEM (2012a,b). 

For this EP, 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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 39 

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).

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 turtle (Dermochelys coriacea), Kemp’s ridley turtle (Lepidochelys kempii), and 

hawksbill turtle (Eretmochelys imbricata) turtles are endangered. The loggerhead turtle 

(Caretta caretta) is currently 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).

Leatherback and loggerhead turtles 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 on the northern Gulf of Mexico coast 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, 2012);

• 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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 40 

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. 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.

Impacts of Support Vessel and Helicopter Traffic

Noise generated from support vessel traffic has the potential to disturb sea turtles, and there is 

also a risk of vessel strikes. Data show that vessel strike 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 water 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).

Noise generated from support 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 MMS (2007b), BOEM (2012a,b), and the 

NMFS Biological Opinion (NMFS, 2007). For this EP, 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. 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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 41 

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 sea surface area 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 (MMS, 2007b; NMFS, 2010b; BOEM, 2012b,d). 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 due to 

the distance from nearest shoreline. 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, and 

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. EP 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).
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 42 

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. 

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, 2012b). 

BOEMRE (2011a) and BOEM (2012b) 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.

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 

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). 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 43 

Figure 3. Location of selected environmental features in relation to the lease area.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 44 

Impacts of a Large Oil Spill (WCD)

The lease area is 133 miles (214 km) from the nearest shorelines inhabited by Piping Plovers 

(Figure 3). The revised OSRA results (BOEMRE, 2011a; BOEM, 2012b) summarized in 

Section A.9.3 (Table 3) predict that there is a 4% 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 MMS (2007b) 

and BOEM (2012a). A large oil spill (WCD) is the only IPF potentially affecting Whooping Cranes. 

A small fuel spill in the lease area would 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

356 miles (573 km) from its critical habitat designated in the Aransas NWR. The revised 

OSRA modeling (BOEM, 2012b) predicts that there is a 0.5% or less probability that an oil spill 

originating in the lease area would reach the Aransas NWR within 30 days and a 5% 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. 
Green Canyon Blocks 859 and 903 October 2013

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 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 MMS (2007b) and BOEM (2012a,b) and 

by NMFS (2007). For this EP, there are no unique site-specific issues with respect to this species.

The lease area is approximately 202 miles (325 km) from the nearest Gulf sturgeon critical 

habitat. The revised OSRA modeling (BOEM, 2012b) 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 Thousand 

Islands/Everglades Unit, which comprises approximately 250,506 ha (619,013 ac) of coastal 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 46 

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 MMS (2007b), BOEM (2012a), and by the NMFS (2007) in its Biological 

Opinion. For this EP, 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. They are 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 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 MMS (2007b, 2008), BOEMRE (2011a), 

and BOEM (2012a). For this EP, there are no unique site-specific issues with respect to these 

species that were not analyzed in these documents. 

The beach mouse habitat is 273 miles (439 km) from the lease area. The revised OSRA modeling 

summarized in Section A.9.3 predicts that a spill in the lease area has a 1% 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 activities 

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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 47 

C.3.11 Elkhorn Coral (Endangered)

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 of Mexico, 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 of Mexico. 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). The GulfCet II study did not estimate bird densities; however, Powers (1987) indicates 

that seabird densities over the open ocean typically are <10 birds/km2

. 

The distributions and relative densities of seabirds within the deepwater areas of the Gulf of 

Mexico, including the project area, vary temporally (i.e., seasonally) and spatially. In GulfCet II 

studies, species diversity and densities varied by hydrographic environment and by the presence 

and relative location of mesoscale features such as Loop Current eddies that may enhance

nutrient levels and productivity of surface waters where these seabird species forage (Hess and 

Ribic, 2000). 

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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 48 

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.

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 MMS (2007b) and BOEM (2012 a,b,d). 

For this EP, 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 could 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 sea surface area 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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 49 

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 MMS (2007b) and BOEM 

(2012 a,b,d). For this EP, 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, 2012b).

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 [<656 ft]). Powers (1987) indicates that 

seabird densities over the open ocean typically are <10 birds/km2

. The number of pelagic birds 

that could be affected in open, offshore waters would depend on the extent and persistence of 

the oil slick.

Data collected following the Macondo spill provided 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 MMS (2007b) and BOEM (2012a).

The Brown Pelican (Pelecanus occidentalis) was delisted from Federal endangered status in 2009 

(USFWS, 2010c). However, this species remains listed as endangered on the Louisiana list of 

Endangered Species (Louisiana Department of Wildlife and Fisheries, 2013), is listed as a species 

of greatest conservation need by the State of Mississippi (Mississippi Department of Wildlife, 

Fisheries and Parks, 2005), 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).
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 50 

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, due to the lease area’s distance from the nearest 

shoreline. 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).

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 are 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)

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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 51 

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. Brown Pelicans are especially at risk from direct and indirect impacts from spilled oil within 

inner shelf and inshore waters, such as embayments. The range of this species is generally 

limited to these waters and surrounding coastal habitats. Brown Pelicans feed on mid-sized fish 

that they capture by diving from above (“plunge diving”) and then scooping the fish into their 

expandable gular pouch. This behavior makes them susceptible to plumage oiling if they feed in 

areas with surface oil or an oil sheen. They may also capture prey that has been physically 

contaminated with oil or has ingested oil. Issues for Brown Pelicans include direct contact with 

oil, disturbance by cleanup activities, and long-term habitat contamination. The Bald Eagle may 

also be at risk from direct and indirect impacts from spilled oil. This species often captures fish 

within shallow water areas (snatching prey from the surface or wading into shallow areas to 

capture prey with their bill) and so may be susceptible to plumage oiling and, as with the Brown 

Pelican, they may also capture prey that has been physically contaminated with oil or has 

ingested oil.

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).

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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 52 

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. The drilling rig ultimately chosen for this project will be in compliance with all 

cooling water intake requirements.

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 (turbulence 

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 MMS (2007b) and

BOEM (2012a,d). For this EP, 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 could mitigate the potential for impacts on pelagic communities, including 

ichthyoplankton. 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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 53 

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 sea surface area 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 because they inhabit the upper layers of the water column and 

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 (2012b) has reexamined the analysis for fish resources and EFH presented in 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). 

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, the nearest of which are, located approximately 61 miles 

(98 km) northwest 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):
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 54 

• Atlantic bluefin tuna (spawn, eggs, 

larvae, adults)

• Bigeye tuna (juveniles, adults)

• Bigeye thresher shark (all)

• Blue marlin (juveniles, adults)

• Longbill spearfish (juveniles, adults)

• Longfin mako shark (all)

• Oceanic whitetip shark (all)

• Sailfish (adults)

• Silky shark (all)

• Skipjack tuna (spawn, adults)

• Swordfish (larvae, juveniles, adults)

• Whale shark (all)

• 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 km2 

(15,000 mi2). 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. However, NOAA did classify 

the bluefin tuna as a species of concern, effectively placing the species 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, 

the 1999 Programmatic Consultation with the elements described above will be followed 

(BOEMRE, 2011a; BOEM, 2012b).

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 HAPC is Jakkula Bank, located approximately 74 miles (119 km) from the 

lease area. 

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).
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 55 

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 could help diminish the potential for impacts on EFH. 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.

Potential spill impacts on EFH are discussed in MMS (2007b) and BOEM (2012a,d). For this EP, 

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 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 sea surface area 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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 56 

A small fuel spill would not affect EFH for corals and coral reefs, the nearest EFH located 

approximately 61 miles (98 km) from 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 MMS (2007b) and BOEM (2012a,d). For this EP, 

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 in 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 61 miles (98 km) from 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 BOEM (2012b) 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., historic 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 OCS blocks with a high potential for historic shipwrecks 

(BOEM, 2012c) and no man-made features were identified within 600 m (2,000 ft) of any of the 

proposed wellsites during the site clearance surveys (Fugro, 2013). Anadarko will abide by the 

applicable requirements of NTL 2005-G07, which stipulate that work be stopped at the project 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 57 

site if any previously undetected archaeological resource is 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. Impacts of a large oil spill (WCD) are the only IPFs 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.

C.6.2 Prehistoric Archaeological Sites

Available evidence suggests that sea level in the northern Gulf of Mexico was at least 91 m 

(300 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. 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 (Coastal Environments, Inc., 1977, 1982). On this basis, the continental 

shelf shoreward of the 45- to 60-m (148- to 197-ft) bathymetric contours has potential for 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 58 

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. 

With water depths between 1,606 and 1,632 m (5,268 and 5,355 ft), the lease area is well 

beyond the 60-m (197-ft) depth contour used by the BOEM 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 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 MMS (2007b), BOEM (2012a,b,d), 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.

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 relate to support vessel 

traffic. The support bases at Port 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 due to the lease 

area’s distance from the nearest shoreline. 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 EP Section K, may have a minor 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 59 

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 MMS (2007b) and BOEM (2012a,b,d). 

Coastal habitats inshore of the project area include barrier beaches and dunes, wetlands, and 

submerged seagrass beds. For this EP, there are no unique site-specific issues with respect to 

coastal habitats.

The revised OSRA modeling summarized in Table 3 predicts that there is a 17% probability of oil 

from a spill in the lease area reaching Texas shorelines within 120 days, a 14% probability of oil 

from a spill in the lease area reaching Louisiana shorelines within 120 days, and a 1% chance of 

oil from a spill in the lease area reaching Mississippi 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 MMS (2007b), BOEM (2012b), 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. 

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, 2012b). 

County or Parish, State Wildlife Refuge, Wilderness Area, or

State/National Park

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 National Wildlife Refuge

Goose Island State Park

Calhoun County, Texas

Mission-Aransas National Estuarine Research Reserve

Aransas National Wildlife Refuge

Matagorda Island State Park

Guadalupe Delta Wildlife Management Area

Welder Flats Coastal Preserve

Matagorda County, Texas

Aransas National Wildlife Refuge

Mad Island Wildlife Management Area

Big Boggy National Wildlife Refuge

San Bernard National Wildlife Refuge

Brazoria County, Texas

San Bernard National Wildlife Refuge

Peach Point Wildlife Management Area

Brazoria National Wildlife Refuge

Christmas Bay State Park 

Christmas Bay Coastal Preserve 
Table 6. (Continued).

Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 60 

County or Parish, State Wildlife Refuge, Wilderness Area, or

State/National Park

Galveston County, Texas

Brazoria National Wildlife Refuge 

Galveston Island State Park

Apffel Park

Seawolf Park

Old Fort Travis Park 

Atkinson Island Wildlife Management Area 

Ft. Anahuac Park

Anahuac National Wildlife Refuge 

McFaddin National Wildlife Refuge

Candy Abshier Wildlife Management Area

Atkinson Island Wildlife Management Area

Chambers County, Texas Anahuac National Wildlife Refuge

McFaddin National Wildlife Refuge

Jefferson County, Texas

McFaddin National Wildlife Refuge

Sea Rim State Park 

Murphree Wildlife Management Area 

Texas Point National Wildlife Refuge 

Cameron Parish, Louisiana

Sabine National Wildlife Refuge 

Cameron Prairie National Wildlife Refuge 

Lacassine National Wildlife Refuge 

Little Pecan Island Natural Area 

Peveto Woods Natural Area

Lower Neches Wildlife Management Area 

Rockefeller Wildlife Management Area 

Vermilion Parish, Louisiana Rockefeller Wildlife Management Area 

Paul J. Rainey Wildlife Management Area

Iberia Parish, Louisiana

Marsh Island Wildlife Management Area

Cypremort Point State Park

Shell Keys National Wildlife Refuge

St. Mary Parish, Louisiana Atchafalaya Delta Wildlife Management Area

Bayoue Teche National Wildlife Refuge

Terrebonne Parish, Louisiana

Atchafalaya Delta Wildlife Management Area

Mandalay National Wildlife Refuge

Isles Dernieres Barrier Islands Refuge

Point Au Chein Wildlife Management Area

Lafourche Parish, Louisiana Point Au Chein Wildlife Management Area

Wisner Wildlife Management Area

Jefferson Parish, Louisiana

Grand Isle State Park

Salvador Wildlife Management Area

Jean Lafitte National Historical Park and Preserve

Lafitte Woods Natural Area

Plaquemines Parish, Louisiana

Salvador Wildlife Management Area

Jean Lafitte National Historical Park and Preserve

Delta National Wildlife Refuge

Pass A Loutre Wildlife Management Area

Breton National Wildlife Refuge

St. Bernard State Park

St. Bernard Parish, Louisiana

Breton National Wildlife Refuge

St. Bernard State Park

Biloxi Wildlife Management Area

Bayou Sauvage National Wildlife Refuge
Table 6. (Continued).

Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 61 

County or Parish, State Wildlife Refuge, Wilderness Area, or

State/National Park

Hancock and Harrison Counties, Mississippi

Hancock County Coastal Marsh Reserve

Buccaneer State Park

Jourdan River Coastal Reserve

Biloxi River Coastal Reserve

Gulf Islands National Seashore

Bayou Sauvage National Wildlife Refuge

Big Branch Marsh National Wildlife Refuge

Pearl River Wildlife Management Area

Wolf River Coastal Reserve

Grand Bayou Coastal Preserve

Bayou Portage Coastal Reserve

Biloxi Marshes State Coastal Preserve

Deer Island State Coastal Preserve

Jackson County, Mississippi

Gulf Islands National Seashore

Davis Bayou Coastal Preserve

Mississippi Sandhill Crane National Wildlife Refuge

Pascagoula River Coastal Reserve

Grand Bay National Estuarine Research Reserve

Grand Bay National Wildlife Refuge

Grand Bay Savannah Coastal Preserve

Deer Island State Coastal Preserve

Old Fort Bayou Coastal Reserve

Bellefontaine Point Coastal Reserve

Graveline Bay Coastal Reserve

Mobile County, Alabama

Grand Bay National Wildlife Refuge

The Grand Bay Savanna Tract

Penalver State Park

Bon Secour National Wildlife Refuge

W.L. Holland Wildlife Management Area

Baldwin County, Alabama

Bon Secour National Wildlife Refuge

Meaher State Park

Weeks Bay National Estuarine Research Reserve

Gulf State Park

Lillian Swamp Mitigation Area

Tarklin Bayou State Preserve

W.L. Holland Wildlife Management Area

Escambia County, Florida

Perdido Key State Recreation Area

Big Lagoon State Recreation Area

Fort Pickens State Park Aquatic Preserve

Gulf Islands National Seashore

Pensacola Bay SWIM Area

Yellow River Wildlife Management Area

Okaloosa County, Florida

Gulf Islands National Seashore

Pensacola Bay SWIM Area

Choctawatchee Bay SWIM Area

Walton County, Florida

Choctawatchee Bay SWIM Area

Henderson State Park

Point Washington Outstanding Florida Water

Walton County, Florida (Continued)

Deer Lake State Park

Grayton Beach State Park Outstanding Florida Water

St. Andrew Bay Watershed SWIM Area
Table 6. (Continued).

Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 62 

County or Parish, State Wildlife Refuge, Wilderness Area, or

State/National Park

Bay County, Florida

Point Washington Outstanding Florida Water

St. Andrew Bay Watershed SWIM Area

St. Andrews State Park Aquatic Preserve

St. Andrews State Park

Gulf County, Florida

St. Andrew Bay Watershed SWIM Area

St. Joseph Peninsula State Park

St. Joseph Bay State Buffer Preserve

Franklin County, Florida

St. Vincent National Wildlife Refuge

Apalachicola National Estuarine Research Reserve

Apalachicola Bay Aquatic Preserve Outstanding Florida Water

Apalachicola River and Bay SWIM Area

Apalachicola River Wildlife and Environmental Area

St. George Island State Park

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; 

BOEMRE, 2011a; BOEM, 2012b).

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, 2012b). 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 63 

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. 

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 onboard 

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 (Pleoticus robustus) are caught by 

trawlers in water depths of about 250 to 550 m (820 to 1,804 ft). Tilefishes (primarily 

Lophalotilus chamaeleonticeps) 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 types of potential 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.

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 could potentially mitigate and reduce the potential for impacts. EP Section H
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 64 

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 sea surface area 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 MMS (2007b) and BOEM (2012b,d). 

For this EP, 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. Data obtained 

following the Macondo spill provided 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 km2 (84,101 mi2

), 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 could potentially alleviate the potential for impacts. EP 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 135 miles (217 km) from the nearest shoreline, 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).

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 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 65 

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 obtained following the Macondo spill provided 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 H2S (e.g., 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 could potentially mitigate and reduce the potential for impacts. 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 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.

Impacts of a Large Oil Spill (WCD)

Potential socioeconomic impacts of an oil spill are discussed in MMS (2007b) and

BOEM (2012a,b,d). For this EP, 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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 66 

In addition to the analyses presented by MMS (2007b, 2008) and BOEM (2012b), 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, 2012b).

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 could potentially help mitigate and reduce the potential for impacts. 

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 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 MMS (2007b) and

BOEM (2012a,b,d). For this EP, there are no unique site-specific issues with respect to these 

impacts.

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, 2012b) as summarized in Section A.9.3 (Table 3), there is a 

12% probability of oil from a spill in the lease area reaching shorelines in Louisiana within 

30 days and a 17% chance of oil contacting shorelines in Texas within 120 days.

In addition to the analysis presented by MMS (2007b; BOEMa,b,d), recent and ongoing studies 

have explored the economic impacts of the Macondo spill, including tourism and “brand” 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 67 

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 3-year period at 

$22.7 billion (Oxford Economics, 2010). 

C.8.5 Land Use

Land use along the northern Gulf Coast is discussed in MMS (2007b) and BOEM (2012a,b,d). 

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 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 Area W-92. Anadarko will comply with BOEM 

requirements and lease stipulations to avoid impacts on uses of the area by military vessels and 

aircraft.

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.

Impacts of a Large Oil Spill (WCD)

An accidental spill would be unlikely to significantly affect shipping or other marine uses. 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.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 68 

D. Environmental Hazards

D.1 Geologic Hazards

The site clearance surveys conducted by Fugro (2013) concluded that the wellsites are free of 

any significant geological hazards and are suitable for the proposed activities. See EP 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 rig 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.

E. Alternatives

No formal alternatives were evaluated in this EIA for an EP. 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 EP Section H. 
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 69 

G. Consultation

No persons or agencies were consulted during the preparation of this EIA.

H. Preparers

The EIA was prepared by CSA Ocean Sciences Inc. Contributors included: 

• M. John Thompson (Senior Scientist);

• John M. Tiggelaar II (Project Scientist);

• Keith VanGraafeiland (Geospatial Manager); 

• Kevin Noack (Geospatial Coordinator); 

• Kristen L. Metzger (Library and Information Services Director);

• LeslieAnn Weekes (Technical Editor); and

• Kim Dunleavy (Technical Editor). 

I. References 

Ackleh, A., G.E. Loup, J.W. Loup, B. Ma, J.J. Newcomb, N. Pal, N.A. Sidorovskaia, and C. Tiemann. 2012. Assessing 

the Deepwater Horizon oil spill impact on marine mammal population through acoustics: Endangered sperm 

whales. J. Acoust. Soc. Am. 131(3): 2,306-2,314.

Anderson, C.M. and R.P. LaBelle. 2000. Update of comparative occurrence rates for offshore oil spills. In: Spill 

Science & Technology Bulletin, Vol. 6, No. 5/6, pp. 303-321. Elsevier Science Ltd., PII: S1353-2561(01) 

00049-4. U.S. Minerals Management Service, Herndon, VA.

Antonio, F.J., R.S. Mendes, and S.M. Thomaz. 2011. Identifying and modeling patterns of tetrapod vertebrate 

mortality rates in the Gulf of Mexico oil spill. Aquatic Toxicology 105(1-2):177-179.

Aten, L.E. 1983. Indians of the upper Texas coast. New York, NY: Academic Press. 370 pp.

Barkaszi, M.J., M. Butler, R. Compton, A. Unietis, and B. Bennet. 2012. Seismic survey mitigation measures and 

marine mammal observer reports. U.S. Department of the Interior, Bureau of Ocean Energy 

Management, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study BOEM 2012-015. 53 pp.

Barkuloo, J.M. 1988. Report on the conservation status of the Gulf of Mexico sturgeon, Acipenser oxyrinchus 

desotoi. U.S. Department of the Interior, U.S. Fish Wildlife Service, Panama City, FL. 33 pp.

Bélanger, L. and J. Bédard. 1989. Responses of staging Greater Snow Geese to human disturbance. J. Wildl. 

Manage. 53:713-719.

Biggs, D.C. and P.H. Ressler. 2000. Water column biology, pp. 141-187. In: Continental Shelf Associates, Inc. 

Deepwater Program: Gulf of Mexico Deepwater Information Resources Data Search and Literature Synthesis. 

Volume I: Narrative Report. U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico 

OCS Region, New Orleans, LA. OCS Study MMS 2000-049.

Boehm, P., D. Turton, A. Raval, D. Caudle, D. French, N. Rabalais, R. Spies, and J. Johnson. 2001. Deepwater 

program: Literature review, environmental risks of chemical products used in Gulf of Mexico deepwater oil 

and gas operations. Volume I: Technical report. U.S. Department of the Interior, Minerals Management 

Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 2001-011. 326 pp.

Brooke, S., and W.W. Schroeder. 2007. State of deep coral ecosystems in the Gulf of Mexico region: Texas to the 

Florida Straits, pp. 271-306. In: S.E. Lumsden, T.F. Hourigan, A.W. Bruckner, and G. Dorr (eds.), The State of 

Deep Coral Ecosystems of the United States. NOAA Tech. Memo. CRCP-3. Silver Spring, MD. 365 pp.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 70 

Bureau of Ocean Energy Management, Regulation and Enforcement. 2010. Federal & Academic Scientists Return 

from Deep-sea Research Cruise in Gulf of Mexico: Scientists Observe Damage to Deep-sea Corals. Online news 

dated 4 November 2010. Website accessed 4 February 2013. 

http://www.noaanews.noaa.gov/stories2010/20101104_coralcruise.html

Bureau of Ocean Energy Management, Regulation and Enforcement. 2011a. Gulf of Mexico OCS Oil and Gas Lease 

Sale: 2011. Western Planning Area Lease Sale 218 Final Supplemental Environmental Impact Statement. 

U.S. Department of the Interior, Bureau of Ocean Energy Management, Regulation and Enforcement Gulf of 

Mexico OCS Region. OCS EIS/EA BOEMRE 2011-034. Accessed 22 January 2013. 

http://www.boem.gov/BOEM-Newsroom/Library/Publications/2011/2011-034-v1.aspx

Bureau of Ocean Energy Management, Regulation and Enforcement. 2011b. Bureau of Ocean Energy 

Management, Regulation and Enforcement Spills – Statistics and Summaries 1996-2011. Website accessed 

4 February 2013. http://www.boem.gov/search-results.aspx?q=spills

Bureau of Ocean Energy Management. 2012a. Gulf of Mexico OCS Oil and Gas Lease Sales: 2012-2017. Western 

Planning Area Lease Sales 229, 233, 238, 246, and 248. Central Planning Area Lease Sales 227, 231, 235, 241, 

and 247. Final Environmental Impact Statement. U.S. Department of the Interior, Bureau of Ocean Energy 

Management, Gulf of Mexico OCS Region. OCS EIS/EA BOEM 2012-019. 3 vols.

Bureau of Ocean Energy Management. 2012b. Gulf of Mexico OCS Oil and Gas Lease Sale: 2012. Central Planning 

Area Lease Sale 216/222. Final Supplemental Environmental Impact Statement. U.S. Department of the 

Interior, Bureau of Ocean Energy Management. Gulf of Mexico OCS Region. New Orleans, LA. 2 volumes. 

OCS EIS/EA BOEM 2012-058. Accessed 19 January 2012.

Bureau of Ocean Energy Management. 2012c. Archaeology Survey Blocks. Website accessed on 22 January 2013. 

http://www.boem.gov/Environmental-Stewardship/Archaeology/surveyblocks-pdf.aspx. 

Bureau of Ocean Energy Management. 2012d. Outer Continental Shelf Oil and Gas Leasing Program: 2012-2017. 

Final Programmatic Environmental Impact Statement. U.S. Department of the Interior, Bureau of Ocean 

Energy Management. OCS EIS/EA BOEM 2012-030.

Camilli, R., C.M. Reddy, D.R. Yoerger, B.A.S. Van Mooy, M.V. Jakuba, J.C. Kinsey, C.P. McIntyre, S.P. Sylva, and 

J.V. Maloney. 2010. Tracking hydrocarbon plume transport and biodegradation at Deepwater Horizon. 

Science DOI: 10.1126/science.1195223.

Carmichael, R.H., W.M. Graham, A. Aven, G.Worthy, and S. Howden. 2012. Were multiple stressors a ‘perfect 

storm’ for northern Gulf of Mexico bottlenose dolphins (Tursiops truncatus) in 2011? PLoS ONE 7(7): e41155. 

doi:10.1371/journal.pone.0041155. 

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0041155

Carr, A. 1996. Suwannee River sturgeon, pp. 73-83. In: M.H. Carr (ed.), A Naturalist in Florida. Yale University 

Press, New Haven, CT.

Centers for Disease Control and Prevention. 2010a. Deepwater Horizon response: NIOSH ongoing health hazard 

evaluation. Website accessed 22 January 2013, updated 24 August 2011. 

http://www.cdc.gov/niosh/topics/oilspillresponse/gulfspillhhe.html

Centers for Disease Control and Prevention. 2010b. Health Hazard Evaluation of Deepwater Horizon Response 

Workers, HETA 2010-0115. Interim Report #6A. 11 pp. Website accessed 4 September 2012. 

http://www.cdc.gov/niosh/hhe/pdfs/interim_report_6.pdf

Clapp, R.B., R.C. Banks, D. Morgan-Jacobs, and W.A. Hoffman. 1982a. Marine birds of the southeastern United 

States and Gulf of Mexico. Part I. Gaviiformes through Pelicaniformes. U.S. Fish and Wildlife Service, Office of 

Biological Services, Washington, DC. FWS/OBS-82/01. 637 pp.

Clapp, R.B., D. Morgan-Jacobs, and R.C. Banks. 1982b. Marine birds of the southeastern United States and Gulf of 

Mexico. Part II. Anseriformes. U.S. Fish and Wildlife Service, Office of Biological Services, Washington, DC. 

FWS/OBS-82/20. 492 pp.

Clapp, R.B., D. Morgan-Jacobs, and R.C. Banks. 1983. Marine birds of the southeastern United States and Gulf of 

Mexico. Part III. Charadriiformes. U.S. Fish and Wildlife Service, Office of Biological Services, Washington, DC. 

FWS/OBS-83/30. 853 pp.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 71 

Coastal Environments, Inc. 1977. Cultural Resources Evaluation of the Northern Gulf of Mexico Continental Shelf. 

Prepared for the U.S. Department of the Interior, National Park Service, Office of Archaeology and Historic 

Preservation, Interagency Archaeological Services, Baton Rouge, LA. 4 vol.

Coastal Environments, Inc. 1982. Sedimentary Studies of Prehistoric Archaeological Sites. Prepared for the U.S. 

Department of the Interior, National Park Service, Division of State Plans and Grants, Baton Rouge, LA.

Collard, S.B. and C. Way. 1997. Chapter 5 – The biological environment. In: Science Applications International 

Corporation (ed.), Northeastern Gulf of Mexico Coastal and Marine Ecosystem Program: Data Search and 

Synthesis; Synthesis Report. U.S. Department of the Interior, U.S. Geological Survey, Biological Resources 

Division and Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. 

USGS/BRD/CR-1997-0005. OCS Study MMS 96-0014. 313 pp.

Continental Shelf Associates, Inc. 1997. Characterization and trends of recreational and commercial fishing from 

the Florida panhandle. U.S. Department of Interior, Minerals Management Service, Gulf of Mexico 

OCS Region, New Orleans, LA. USGS/BRD/CR-1997-0001 and OCS Study MMS 97-0020. 333 pp.

Continental Shelf Associates, Inc. 2002. Deepwater Program: Bluewater fishing and OCS activity, interactions 

between the fishing and petroleum industries in deepwaters of the Gulf of Mexico. U.S. Department of the 

Interior, Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study 

MMS 2002-078.

Continental Shelf Associates, Inc. 2004. Final Report: Gulf of Mexico Comprehensive Synthetic Based Muds 

Monitoring Program. Report prepared for SBM Research Group, Houston, TX. October 2004. 3 volumes.

Continental Shelf Associates, Inc. 2006. Effects of oil and gas exploration and development at selected continental 

slope sites in the Gulf of Mexico. Volume II: Technical report. U.S. Department of the Interior, Minerals 

Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 2006-045.

Cruz-Kaegi, M.E. 1998. Latitudinal variations in biomass and metabolism of benthic infaunal communities. 

Ph.D. dissertation, Texas A&M University, College Station, TX.

CSA International, Inc. 2007. Characterization of northern Gulf of Mexico deepwater hard- bottom communities 

with emphasis on Lophelia coral. U.S. Department of the Interior, Minerals Management Service, Gulf of 

Mexico OCS Region, New Orleans, LA. OCS Study MMS 2007-044. 169 pp. + app.

Davis, R.W. and G.S. Fargion. 1996. Distribution and abundance of cetaceans in the north-central and western 

Gulf of Mexico: Final report. U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico 

OCS Region, New Orleans, LA. Website accessed 4 February 2013. 

Vol I. http://www.data.boem.gov/PI/PDFImages/ESPIS/3/3296.pdf

Vol. II. http://www.data.boem.gov/PI/PDFImages/ESPIS/3/3297.pdf

Vol. III. http://www.data.boem.gov/PI/PDFImages/ESPIS/3/3301.pdf

Davis, R.W., J.G. Ortega-Ortiz, C.A. Ribic, W.E. Evans, D.C. Biggs, P.H. Ressler, J.H. Wormuth, R.R. Leben, K.D. Mullin, 

and B. Würsig. 2000. Cetacean habitat in the northern Gulf of Mexico, pp. 217-253. In: R.W. Davis, 

W.E. Evans, and B. Würsig (eds.), Cetaceans, sea turtles, and seabirds in the northern Gulf of Mexico: 

Distribution, abundance and habitat associations. Volume II: Technical report. U.S. Geological Survey, 

Biological Resources Division, USGS/BRD/CR-1999-0006 and U.S. Department of the Interior, Minerals 

Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 2000-003. 346 pp. 

Website accessed 4 September 2012.

http://www.tamug.edu/marb/davisdocs/Deep-Sea%20Res%202001%20Davis%20etal.pdf

Ditty, J.G. 1986. Ichthyoplankton in neretic waters of the northern Gulf of Mexico off Louisiana: Composition, 

relative abundance, and seasonality. Fish. Bull. 84(4):935-946.

Ditty, J.G., G.G. Zieske, and R.F. Shaw. 1988. Seasonality and depth distribution of larval fishes in the northern 

Gulf of Mexico above 26°00’N. Fish. Bull. 86:811-823.

Earthjustice. 2011. Comments on Shell Exploration Plan S-7445, Document ID: BOEM-2011-0006-0001, 

Docket ID: BOEM-2011-0006, 6 February 2011. 18 pp.

Efroymson, R.A., W.H. Rose, S. Nemeth, and G.W. Suter II. 2000. Ecological risk assessment framework for low 

altitude overflights by fixed-wing and rotary-wing military aircraft. Report prepared by Oak Ridge National 

Laboratory, Oak Ridge, TN. ORNL/TM-2000/289: ES-5048.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 72 

Ehrlich, P.R., D.S. Dobkin, and D. Wheye. 1992. Birds in Jeopardy: The Imperiled and Extinct Birds of the United 

States and Canada, including Hawaii and Puerto Rico. Stanford University Press, Palo Alto, CA. 261 pp.

Florida Fish and Wildlife Conservation Commission. 2012. Florida's endangered and threatened species. Website 

accessed 28 August 2013. http://myfwc.com/media/1515251/Threatened_Endangered_Species.pdf

Flower Garden Banks National Marine Sanctuary. 2011. Cnidarian species. Website accessed 4 September 2012, 

updated 22 August 2012. http://flowergarden.noaa.gov/about/cnidarianlist.html

Fox, D.A., J.E. Hightower, and F.M. Paruka. 2000. Gulf sturgeon spawning migration and habitat in the 

Choctawhatchee River system, Alabama-Florida. Trans. Am. Fish. Soc. 129:811-826.

Fritts, T.H. and R.P. Reynolds. 1981. Pilot study of the marine mammals, birds, and turtles in OCS areas of the Gulf 

of Mexico. U.S. Department of the Interior, Fish and Wildlife Service, Biological Services Program. 

FWS/OBS-81/36.

Fugro Geoconsulting, Inc. 2013. Wellsite Clearance Letters for Proposed Wellsites, Blocks GC 859 and GC 903. 

Green Canyon Area, Gulf of Mexico. Letter Report Nos. 27.2013-2632-903-D, 27.2013-2632-903-E, 27.2013-

2632-859-F, 27.2013-2632-859-G, 27.2013-2632-859-H, 27.2013-2632-859-I, and 37.2013-2632-859-J. 

Gallaway, B. (ed.). 1988. Northern Gulf of Mexico continental slope study, final report: Year 4. Volume II: 

Synthesis report. Final report submitted to the Minerals Management Service, New Orleans, LA. 

Contract No. 14-12-0001-30212.

Gallaway, B.J., J.G. Cole, and R.G. Fechhelm. 2003. Selected Aspects of the Ecology of the Continental Slope Fauna 

of the Gulf of Mexico: A Synopsis of the Northern Gulf of Mexico Continental Slope Study, 1983-1988. 

U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. 

OCS Study MMS 2003-072.

Geraci, J.R. and D.J. St. Aubin. 1987. Effects of offshore oil and gas development on marine mammals and turtles, 

pp. 587-617. In: D.F. Boesch and N.N. Rabalais (eds.), Long Term Environmental Effects of Offshore Oil and 

Gas Development. Elsevier Applied Science Publ. Ltd., London and New York.

Geraci, J.R. and D.J. St. Aubin. 1990. Sea Mammals and Oil: Confronting the Risks. Academic Press, San Diego.

Goold, J.C. and S.E. Jones. 1995. Time and frequency domain characteristics of sperm whale clicks. J. Acoust. Soc. 

Am. 98:1,279–1,291.

Gulf of Mexico Fishery Management Council. 2005. Generic Amendment Number 3 for addressing Essential Fish 

Habitat Requirements, Habitat Areas of Particular Concern, and adverse effects of fishing in the following 

Fishery Management Plans of the Gulf of Mexico: Shrimp fishery of the Gulf of Mexico, United States waters 

red drum fishery of the Gulf of Mexico, reef fish fishery of the Gulf of Mexico coastal migratory pelagic 

resources (mackerels) in the Gulf of Mexico and South Atlantic, stone crab fishery of the Gulf of Mexico, spiny 

lobster in the Gulf of Mexico and South Atlantic, coral and coral reefs of the Gulf of Mexico. Gulf of Mexico 

Fishery Management Council, Tampa, FL.

Hazen, T.C., E.A. Dubinsky, T.Z. DeSantis, G.L. Andersen, Y.M. Piceno, N. Singh, J.K. Jansson, A. Probst, S.E. Borglin, 

J.L. Fortney, W.T. Stringfellow, M. Bill, M.S. Conrad, L.M. Tom, K.L. Chavarria, T.R. Alusi, R. Lamendella, 

D.C. Joyner, C. Spier, J. Baelum, M. Auer, M.L. Zemla, R. Chakraborty, E.L. Sonnenthal, P. D’haeseleer, 

H.N. Holman, S. Osman, Z. Lu, J.D. Van Nostrand, Y. Deng, J. Zhou, and O.U. Mason. 2010. Deep-sea oil plume 

enriches indigenous oil-degrading bacteria. Science DOI: 10.1126/science.1195979.

Hess, N.A. and C.A. Ribic. 2000. Seabird ecology, pp. 275-315. In: R.W. Davis, W.E. Evans, and B. Würsig (eds.), 

Cetaceans, sea turtles, and seabirds in the northern Gulf of Mexico: Distribution, abundance and habitat 

associations. Volume II: Technical report. U.S. Geological Survey, Biological Resources Division, 

USGS/BRD/CR-1999-0006 and U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico 

OCS Region, New Orleans, LA. OCS Study MMS 2000-003. 346 pp.

Higashi, G.R. 1994. Ten years of fish aggregating device (FAD) design and development in Hawaii. Bull. Mar. 

Sci. 55(2-3):651-666.

Holand, P. 1997. Offshore Blowouts: Causes and Control. Gulf Publishing Co., Houston, TX. ISBN 0884155145.

Holland, K.R., R.W. Brill, and R.K.C. Chang. 1990. Horizontal and vertical movements of yellowfin and bigeye tuna 

associated with fish aggregating devices. Fish. Bull. 88:493-507.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 73 

Holt, M. M., D.P. Noren, V. Veirs, C.K. Emmons, and S. Veirs. 2009. Speaking up: Killer whales (Orcinus orca) 

increase their call amplitude in response to vessel noise. J. Acoust. Soc. Am. 125(1):27-32.

IEM. 2010. A Study of the Economic Impact of the Deepwater Horizon Oil Spill. Prepared for Greater 

New Orleans, Inc. October 2010. Website accessed 4 February 2013. 

http://gnoinc.org/wp-content/uploads/Economic_Impact_Study_Part_I_-_Full_Report.pdf

http://gnoinc.org/wp-content/uploads/Economic_Impact_Study_Part_II_-_Moratoria_FINAL.pdf

http://gnoinc.org/wp-content/uploads/Economic_Impact_Study_Part_III_-_Public_Perception_FINAL.pdf

Inter-Agency Economic Report. 2010. Estimating the effects of the deepwater drilling moratorium on the Gulf 

coast economy. September 2010. Website accessed 4 September 2012. 

http://www.esa.doc.gov/Reports/estimating-economic-effects-deepwater-drilling-moratorium-gulf-coasteconomy

Intergovernmental Panel on Climate Change. 2007. Climate Change 2007: Synthesis Report. Contribution of 

Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate 

Change. Geneva, Switzerland. 104 pp.

International Association of Oil & Gas Producers. 2010. Risk assessment data directory: Blowout frequencies. 

IAGP Report No. 434-2. March 2010. Website accessed 4 September 2012. 

http://www.ogp.org.uk/pubs/434-02.pdf

Ji, Z-G., W.R. Johnson, C.F. Marshall, and E.M. Lear. 2004. Oil-Spill Risk Analysis: Contingency Planning Statistics 

for Gulf of Mexico OCS Activities. U.S. Department of the Interior, Minerals Management Service, Gulf of 

Mexico OCS Region. OCS Report MMS 2004-026.

Jochens, A., D. Biggs, K. Benoit-Bird, D. Engelhaupt, J. Gordon, C. Hu, N. Jaquet, M. Johnson, R. Leben, B. Mate, 

P. Miller, J. Ortega-Ortiz, A. Thode, P. Tyack, and B. Würsig. 2008. Sperm whale seismic study in the Gulf of 

Mexico: Synthesis report. U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico 

OCS Region, New Orleans, LA. OCS Study MMS 2008-006. 341 pp.

Johnsgard, P.A. 1990. Hawks, Eagles, and Falcons of North America; Biology and Natural History. Smithsonian 

Institute Press, Washington. 403 pp.

Joint Analysis Group. 2010a. Joint Analysis Group (JAG) review of preliminary data to examine subsurface oil in 

the vicinity of MC252#1 May 19 to June 19, 2010. Website accessed 4 September 2012. 

http://gomex.erma.noaa.gov/layerfiles/7229/files/JAG_Data_Report_2_Subsurface%20Oil_Final.pdf

Joint Analysis Group. 2010b. Joint Analysis Group (JAG) review of R/V Brooks McCall data to examine subsurface 

oil. Website accessed 4 February 2013. 

http://www.noaa.gov/sciencemissions/PDFs/JAG_Report_1_BrooksMcCall_Final_June20.pdf

Joint Analysis Group. 2010c. Joint Analysis Group (JAG) review of preliminary data to examine oxygen levels in the 

vicinity of MC252#1 May 8 to August 9, 2010. Website accessed 4 September 2012. 

http://www.noaa.gov/sciencemissions/PDFs/JAG_Oxygen_Report%20%28FINAL%20090410%29.pdf

Kennicutt, M.C. II. 2000. Chemical Oceanography, pp. 123-139. In: Continental Shelf Associates, Inc. Deepwater 

Program: Gulf of Mexico deepwater information resources data search and literature synthesis. Volume I: 

Narrative report. U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, 

New Orleans, LA. OCS Study MMS 2000-049.

LGL Ecological Research Associates, Ltd. 2006. Assessment of the effects of underwater noise from the proposed 

Neptune LNG Project - Supplementary Biological Effects Report to Ecology and Environment, Inc. LGL Report 

No. 4200-2a, 8 August 2006. 11 pp.

Lohoefener, R., W. Hoggard, K. Mullin, C. Roden, and C. Rogers. 1990. Association of sea turtles with petroleum 

platforms in the north-central Gulf of Mexico. U.S. Department of the Interior, Minerals Management Service, 

Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 90-0025. 90 pp.

Louisiana Department of Wildlife and Fisheries. 2013. Tracking List and Fact Sheets. Website accessed 

2 April 2013. http://www.wlf.louisiana.gov/wildlife/rare-animals-fact-sheets 

Lutcavage, M.E., P.L. Lutz, G.D. Bossart, and D.M. Hudson. 1995. Physiologic and clinicopathologic effects of crude 

oil on loggerhead sea turtles. Arch. Environ. Contam. Toxicol. 28:417-422.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 74 

Lutcavage, M.E., P. Plotkin, B. Witherington, and P.L. Lutz. 1997. Human impacts on sea turtle survival, 

pp. 387-409. In: P.L. Lutz and J.A. Musick (eds.), The Biology of Sea Turtles. CRC Press, Boca Raton, FL.

MacDonald, I.R. (ed.). 2002. Stability and Change in Gulf of Mexico Chemosynthetic Communities. Volume II: 

Technical Report. U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, 

New Orleans, LA. OCS Study MMS 2002-036. 456 pp.

Marine Mammal Commission. 2011. Assessing the long-term effects of the BP Deepwater Horizon oil spill on

marine mammals in the Gulf of Mexico: A statement of research needs. Website accessed 22 January 2013. 

http://www.mmc.gov/reports/workshop/pdf/longterm_effects_bp_oilspil.pdf

Minerals Management Service. 2000. Gulf of Mexico Deepwater Operations and Activities: Environmental 

Assessment. U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, 

New Orleans, LA. OCS EIS/EA MMS 2000-001.

Minerals Management Service. 2007a. Outer Continental Shelf Oil & Gas Leasing Program: 2007-2012 Final 

Environmental Impact Statement. U.S. Department of the Interior, Minerals Management Service, Herndon, 

VA. OCS EIS/EA MMS 2007-003. April 2007.

Minerals Management Service. 2007b. Gulf of Mexico OCS Oil and Gas Lease Sales: 2007-2012. Western Planning 

Area Sales 204, 207, 210, 215, and 218; Central Planning Area Sales 205, 206, 208, 213, 216, and 222. Final 

Environmental Impact Statement. U.S. Department of the Interior, Minerals Management Service, Gulf of 

Mexico OCS Region. OCS EIS/EA MMS 2007-018. April 2007.

Minerals Management Service. 2008. Gulf of Mexico OCS Oil and Gas Lease Sales: 2009-2012; Central Planning 

Area Sales 208, 213, 216, and 222; Western Planning Area Sales 210, 215, and 218. Final Supplemental 

Environmental Impact Statement. U.S. Department of the Interior, Minerals Management Service, Gulf of 

Mexico OCS Region, New Orleans, LA. OCS EIS/EA MMS 2008-041. September 2008.

Minerals Management Service. 2009a. NTL No. 2009-G39: Biologically Sensitive Underwater Features and Areas. 

U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. 

Minerals Management Service. 2009b. NTL No. 2009-G40: Deepwater Benthic Communities. U.S. Department of 

the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA.

Mississippi Department of Wildlife, Fisheries and Parks. 2005. Mississippi’s species of greatest conservation need 

by ecoregion. In: Mississippi's Comprehensive Wildlife Conservation Strategy 2005 – 2015, App. VIII 

pp. 375-380. Website accessed 9 September 2013. http://www.mdwfp.com/media/63792/cwcs.pdf

Morrow, J.V., Jr., J.P. Kirk, K.J. Killgore, H. Rugillio, and C. Knight. 1998. Status and recovery of Gulf sturgeon in the 

Pearl River system, Louisiana-Mississippi. North American Journal of Fisheries Management 18:798-808.

Mullin, K., W. Hoggard, C. Roden, R. Lohoefener, C. Rogers, and B. Taggart. 1991. Cetaceans on the upper 

continental slope in the north-central Gulf of Mexico. OCS Study/MMS 910027. U.S. Department of the 

Interior, Minerals Management Service, Gulf of Mexico OCS Regional Office, New Orleans, LA. 108 pp.

National Marine Fisheries Service. 2007. Endangered Species Act, Section 7 Consultation – Biological Opinion. 

Gulf of Mexico Oil and Gas Activities: Five-Year Leasing Plan for Western and Central Planning Areas 

2007-2012. 29 June 2007.

National Marine Fisheries Service. 2009. Final Amendment 1 to the Consolidated Atlantic Highly Migratory 

Species Fishery Management Plan Essential Fish Habitat. Highly Migratory Species Management Division, 

Office of Sustainable Fisheries, Silver Spring, MD. June 2009. Website accessed 4 September 2012. 

http://www.nmfs.noaa.gov/sfa/hms/EFH/Final/FEIS_Amendment_Total.pdf

National Marine Fisheries Service. 2010a. Final Recovery Plan for the Sperm Whale (Physeter macrocephalus). 

Website accessed 4 September 2012. 

http://www.nmfs.noaa.gov/pr/pdfs/recovery/final_sperm_whale_recovery_plan_21dec.pdf

National Marine Fisheries Service. 2010b. Gulf sturgeon (Acipenser oxyrinchus desotoi). Website accessed 

4 September 2012, updated 14 March 2012. http://www.nmfs.noaa.gov/pr/species/fish/gulfsturgeon.htm

National Marine Fisheries Service. 2010c. Sea turtles, dolphins, and whales and the Gulf of Mexico oil spill. 

Website accessed 4 September 2012, updated 12 September 2011. 

http://www.nmfs.noaa.gov/pr/health/oilspill.htm
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 75 

National Marine Fisheries Service . 2010d. Deepwater Horizon/BP oil spill: size and percent coverage of fishing 

area closures due to BP oil spill. Website accessed 4 February 2013. 

http://sero.nmfs.noaa.gov/deepwater_horizon/size_percent_closure/index.html

National Marine Fisheries Service. 2013. Draft marine mammal stock assessment reports (SARs). Updated 

January 23, 2013. http://www.nmfs.noaa.gov/pr/sars/draft.htm

National Marine Fisheries Service , U.S. Fish and Wildlife Service, and SEMARNAT. 2011. Bi-National Recovery Plan 

for the Kemp‘s Ridley Sea Turtle (Lepidochelys kempii), Second Revision. National Marine Fisheries Service. 

Silver Spring, Maryland. Website accessed 4 February 2013. 

http://www.nmfs.noaa.gov/pr/pdfs/recovery/kempsridley_revision2.pdf

National Oceanic and Atmospheric Administration. 2006. Fact Sheet: Small Diesel Spills (500-5,000 gallons). 

NOAA Scientific Support Team, Hazardous Materials Response and Assessment Division, National Oceanic and 

Atmospheric Administration. Seattle, Washington. 2 pp.

National Park Service. 2010. Breton Wilderness 300 km Radius. Website accessed 4 February 2013. 

http://www2.nature.nps.gov/air/Permits/ARIS/docs/bretMap300.pdf

National Research Council. 1983. Drilling Discharges in the Marine Environment. National Academy Press, 

Washington, DC. 180 pp.

National Research Council. 2003a. Oil in the Sea III: Inputs, Fates, and Effects. National Academies Press, 

Washington, DC. 182 pp. + app.

National Research Council. 2003b. Ocean Noise and Marine Mammals. Ocean Studies Board, National Academies 

Press, Washington, DC. 204 pp.

Nederlandse Aardolie Maatschappij. 2007. Green light to birds: Investigation into the effect of bird-friendly 

lighting. Nederlandse Aardolie Maatschappij, Assen, The Netherlands.

Neff, J.M. 1987. Biological effects of drilling fluids, drill cuttings and produced waters, pp. 469-538. 

In: D.F. Boesch and N.N. Rabalais (eds.), Long-Term Effects of Offshore Oil and Gas Development. Elsevier 

Applied Science Publishers, London.

Neff, J.M., S. McKelvie, and R.C. Ayers, Jr. 2000. Environmental impacts of synthetic based drilling fluids. 

Prepared by Robert Ayers & Associates, Inc. U.S. Department of the Interior, Minerals Management Service, 

Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 2000-064. 118 pp.

Neff, J.M., A.D. Hart, J.P. Ray, J.M. Limia, and T.W. Purcell. 2005. An assessment of seabed impacts of 

synthetic-based drilling-mud cuttings in the Gulf of Mexico. 2005 SPE/EPA/DOE Exploration and Production 

Environmental Conference, 7-9 March 2005, Galveston, Texas, USA. SPE 94086.

Nelson, H.F. and E.E. Bray. 1970. Stratigraphy and History of the Holocene Sediments in the Sabine-High Island 

Area, Gulf of Mexico. In: Morgam, J.P. (ed.) Deltaic Sedimentation; Modern and Ancient. Special Publn. 

No. 15. Tulsa, OK: SEPM.

Nowlin, W.D., Jr., A.E. Jochens, S.F. DiMarco, R.O. Reid, and M.K. Howard. 2001. Deepwater Physical 

Oceanography Reanalysis and Synthesis of Historical Data: Synthesis Report. U.S. Department of the Interior, 

Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA. OCS Study MMS 2001-064. 

528 pp.

Operational Science Advisory Team. 2010. Summary report for sub-sea and sub-surface oil and dispersion 

detection: Sampling and monitoring. Operational Science Advisory Team (OSAT) Unified Area Command

131 pp.

OSPAR Commission. 2012. Report of the OSPAR Workshop on research into possible effects of regular platform 

lighting on specific bird populations.

Oxford Economics. 2010. Potential impact of the Gulf oil spill on tourism. Report prepared for the U.S. Travel 

Association. Website accessed 4 September 2012. 

http://www.ustravel.org/sites/default/files/page/2009/11/Gulf_Oil_Spill_Analysis_Oxford_Economics_710.pdf.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 76 

Peake, D.E. 1996. Bird surveys, pp. 271-304. In: R.W. Davis and G.S. Fargion (eds.), Distribution and abundance of 

cetaceans in the north-central and western Gulf of Mexico, Final report. Volume II: Technical report. 

Prepared by the Texas Institute of Oceanography and the National Marine Fisheries Service. U.S. Department 

of the Interior, Minerals Management Service, Gulf of Mexico OCS Region Office, New Orleans, LA. OCS Study 

MMS 96-0027. 357 pp.

Pearson, C.E., D.B. Kelley, R.A. Weinstein, and S.W. Gagliano. 1986. Archaeological investigations on the Outer 

Continental Shelf: A study within the Sabine River valley, offshore Louisiana and Texas. U.S. Department of 

the Interior, Minerals Management Service, Reston, VA. OCS Study MMS 86-0119. 314 pp.

Poot, H., B.J. Ens, H. de Vries, M.A.H. Donners, M.R. Wernand, and J.M. Marquenie. 2008. Green light for 

nocturnally migrating birds. Ecology and Society 13(2):47. Website accessed 22 January 2013. 

http://www.ecologyandsociety.org/vol13/iss2/art47/

Powers, K. 1987. Seabirds, pp. 194-201. In: J.D. Milliman and W.R. Wright (eds.), The Marine Environment of the 

U.S. Atlantic Continental Slope and Rise. Jones and Bartlett Publ., Inc. Boston/Woods Hole, MA. 275 pp.

Pritchard, P.C.H. 1997. Evolution, phylogeny, and current status.pp. 1-28. In: Lutz, P.L. and J.A. Musick (eds.), The

Biology of Sea Turtles. Boca Raton, FL: CRC Press.

Rathbun, G.B. 1988. Fixed-wing airplane versus helicopter surveys of manatees. Mar. Mamm. Sci. 4(1):71-75.

Relini, M., L.R. Orsi, and G. Relini. 1994. An offshore buoy as a FAD in the Mediterranean. Bull. Mar. Sci. 

55(2-3):1,099-1,105.

Richards, W.J., T. Leming, M.F. McGowan, J.T. Lamkin, and S. Kelley-Farga. 1989. Distribution of fish larvae in 

relation to hydrographic features of the Loop Current boundary in the Gulf of Mexico. Rapp. P.-v. Reun.

Cons. Int. Explor. Mer. 191:169-176.

Richards, W.J., M.F. McGowan, T. Leming, J.T. Lamkin, and S. Kelley. 1993. Larval fish assemblages at the Loop 

Current boundary in the Gulf of Mexico. Bull. Mar. Sci. 53(2):475-537.

Richardson, W.J., C.R. Greene, Jr., C.I. Malme, and D.H. Thomson. 1995. Marine Mammals and Noise. Academic 

Press, San Diego. 576 pp.

Rodgers, J., Jr, and S. Schwikert. 2002. Buffer Zone Distances to Protect Foraging and Loafing Waterbirds from 

Disturbances by Personal Watercraft and Outboard-Powered Boats. Conservation Biology 16:216-224.

Rowe, G.T. and M.C. Kennicutt II. 2009. Northern Gulf of Mexico Continental Slope Habitats and Benthic Ecology 

Study. Final Report. U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico 

OCS Region, New Orleans, LA. OCS Study MMS 2009-039. 456 pp.

Russell, R.W. 2005. Interactions between migrating birds and offshore oil and gas platforms in the northern Gulf 

of Mexico: Final Report. U.S. Department of the Interior, Minerals Management Service, Gulf of Mexico 

OCS Region, New Orleans, LA. OCS Study MMS 2005-009. 348 pp.

Salmon, M. and J. Wyneken. 1990. Do swimming loggerhead sea turtles (Caretta caretta) use light cues for 

offshore orientation? Marine and Freshwater Behaviour and Physiology 17(4): 233-246.

Share the Beach. 2010. Nesting season statistics. Website accessed 4 September 2012. 

http://www.alabamaseaturtles.com/nesting-season-statistics/

Smultea, M.A., J.R. Mobley, Jr., D. Fertl, and G.L. Fulling. 2008. An unusual reaction and other observations of 

sperm whales near fixed wing aircraft. Gulf and Caribbean Research 20:75-80.

Solomon, G.M. and S. Janssen. 2010. Health Effects of the Gulf Oil Spill. Journal of the American Medical 

Association. Website accessed 4 September 2012.

http://www.asquifyde.es/uploads/documentos/Health-Effects-of-the-Gulf-Oil-Spill.pdf

Southall, B.L., A.E. Bowles, W.T. Ellison, J.J. Finneran, R.L. Gentry, C.R. Greene, Jr., D. Kastak, D.R. Ketten, J.H. Miller, 

P.E. Nachtigall, W.J. Richardson, J.A. Thomas, and P.L.Tyack. 2007. Marine mammal noise exposure criteria: 

initial scientific recommendation. Aquatic Mammals 33, 411–521

Sulak, K.J. and J.P. Clugston. 1998. Early life history stages of Gulf sturgeon in the Suwannee River, Florida. 

Trans. Am. Fish. Soc. 127:758-771.

Todd, V. L. G., W.D. Pearse, N.C. Tregenza, P.A. Lepper, and I.B. Todd. 2009. Diel echolocation activity of harbour 

porpoises (Phocoena phocoena) around North Sea offshore gas installations. ICES Journal of Marine Science, 

66: 734–745.
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 77 

Tuxbury, S.M. and M. Salmon. 2005. Competitive interactions between artificial lighting and natural cues during 

seafinding by hatchling marine turtles. Biol. Conserv. 121: 311-316.

U.S. Fish and Wildlife Service. 2001. Florida manatee recovery plan (Trichechus manatus latirostris), Third 

Revision. U.S. Fish and Wildlife Service, Southeast Region, Atlanta, GA.

U.S. Fish and Wildlife Service. 2003. Recovery plan for the Great Lakes Piping Plover (Charadrius melodus). 

Fort Snelling, Minnesota. September 2003.

U.S. Fish and Wildlife Service. 2007. International Recovery Plan: Whooping Crane (Grus americana), Third 

Revision. Albuquerque, New Mexico. March 2007.

U.S. Fish and Wildlife Service. 2010a. All about piping plovers. Website accessed 4 February 2013. 

http://www.fws.gov/plover/facts.html

U.S. Fish and Wildlife Service. 2010b. Beach Nesting Birds of the Gulf. Website accessed 4 February 2013. 

http://www.fws.gov/home/dhoilspill/pdfs/DHBirdsOfTheGulf.pdf

U.S. Fish and Wildlife Service. 2010c. Species information, threatened and endangered animals and plants. 

Website accessed 4 February 2013. http://www.fws.gov/endangered/

U.S. Fish and Wildlife Service. 2010d. Weekly bird impact data and consolidated wildlife reports. Website 

accessed 4 February 2013. http://www.fws.gov/home/dhoilspill/collectionreports.html

U.S. Fish and Wildlife Service. 2010e. Effects of oil on wildlife and habitat. Website accessed 4 February 2013. 

http://www.fws.gov/home/dhoilspill/pdfs/DHJICFWSOilImpactsWildlifeFactSheet.pdf

U.S. Fish and Wildlife Service. 2011. FWS Deepwater Horizon Oil Spill Response. Bird Impact Data and 

Consolidated Wildlife Reports. Deepwater Horizon Bird Impact Data from the DOI-ERDC NRDA Database 

12 May 2011. Website accessed 4 February 2013. 

http://www.fws.gov/home/dhoilspill/pdfs/Bird%20Data%20Species%20Spreadsheet%2005122011.pdf

U.S. Fish and Wildlife Service and Gulf States Marine Fisheries Commission. 1995. Gulf Sturgeon Recovery Plan. 

Atlanta, Georgia. 170 pp. Website accessed 4 September 2012. 

http://www.nmfs.noaa.gov/pr/pdfs/recovery/sturgeon_gulf.pdf

Wakeford, A. 2001. State of Florida conservation plan for Gulf sturgeon (Acipencer oxyrinchus desotoi). Florida 

Marine Research Institute Technical Report TR-8. St. Petersburg, FL.

Waring, G.T., E. Josephson, K. Maze-Foley, and P.E. Rosel (eds.). 2012. U.S. Atlantic and Gulf of Mexico Marine 

Mammal Stock Assessments - 2011. NOAA Tech Memo NMFS NE 221. 330 pp. 

http://nefsc.noaa.gov/publications/tm/tm221/tm221.pdf. 

Wartzok, D. and D. Ketten. 1999. Marine mammal sensory systems, pp. 117-175. In: J.E. Reynolds and S. Rommel 

(eds.), Biology of Marine Mammals. Smithsonian Institution Press, Washington.

Weilgart, L. and H. Whitehead. 1993. Coda communication by sperm whales (Physeter macrocephalus) off the 

Galapagos Islands. Can. J. Zool. 71:744–752.

White, H.K., P. Hsing, W. Cho, T.M. Shank, E.E. Cordes, A.M. Quattrini, R.K. Nelson, R. Camilli, A.W.J. Demopoulous, 

C.R. German, J.M. Brooks, H.H. Roberts, W. Shedd, C.M. Reddy, and C.R. Fisher. 2012. Impact of the 

Deepwater Horizon oil spill on a deep-water coral community in the Gulf of Mexico. Proceedings of the 

National Academy of Sciences (Early Edition). doi:10.1073/pnas.1118029109. Website accessed 

22 January 2013. http://www.pnas.org/content/early/2012/03/23/1118029109.full.pdf+html?sid=56e8cdfe2830-43f8-9d08-8eca0efd27e2

Whooping Crane Eastern Partnership. 2010. About whooping cranes and their recovery. Website accessed 

4 February 2013. http://www.bringbackthecranes.org/technicaldatabase/index.html#RecoveryReports

Wiese, F.K., W.A. Montevecchi, G.K. Davoren, F. Huettmann, A.W. Diamond, and J. Linke. 2001. Seabirds at risk 

around offshore oil platforms in the north-west Atlantic. Mar. Poll. Bull. 42(12):1,285-1,290.

Wei, C-L. 2006. The bathymetric zonation and community structure of deep-sea macrobenthos in the northern 

Gulf of Mexico. M.S. thesis, Texas A&M University. Website accessed 4 September 2012. 

http://repository.tamu.edu/handle/1969.1/4927

Wilson, J. 2003. Manatees in Louisiana. Louisiana Marine Education Resources. July/August 2003. 7 pp. Website 

accessed 4 September 2012. http://www.lamer.lsu.edu/pdfs/Manatees_LaConservArticle.pdf
Green Canyon Blocks 859 and 903 October 2013

Environmental Impact Analysis for Supplemental Exploration Plan Page 78 

Witherington, B.E. 1997. The problem of photopollution for sea turtles and other nocturnal animals, pp. 303-328. 

In: J.R. Clemmons and R. Buchholz (eds.), Behavioral Approaches to Conservation in the Wild. Cambridge 

University Press, Cambridge, England.

Würsig, B., S.K. Lynn, T.A. Jefferson, and K.D. Mullin. 1998. Behaviour of cetaceans in the northern Gulf of Mexico 

relative to survey ships and aircraft. Aquatic Mammals 24: 41-50.

Würsig, B., T.A. Jefferson, and D.J. Schmidly. 2000. The Marine Mammals of the Gulf of Mexico. Texas A&M 

University Press, College Station, TX. 232 pp.
 

O 

ADMINISTRATIVE INFORMATION 

(a) Proprietary Information 

Proprietary copies of this plan contain information not available to the public and include 

structure maps, seismic information, cross sections, depths of wells, etc. 

(b) Bibliography 

Shallow Hazards Report 

Final Sale Package for Central Gulf of Mexico Sale Number 182.