Response to Comments OCS-EPA-R4019 and - R4020 BlackHawk BlackHornet

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 4

Final Determination and Response to Comments for

Outer Continental Shelf Air Permits OCS-EPA-R4019 and OCS-EPA-R4020

Anadarko Petroleum Corporation

On November 14, 2014, the Region 4 office of the United States Environmental Protection Agency (EPA) 

requested public comment on two draft Outer Continental Shelf (OCS) air permits for Anadarko Petroleum 

Corporation (Anadarko), 1201 Lake Robbins Drive, The Woodlands, Texas 77380. The permits will regulate air 

pollutant emissions from exploratory drilling operations within the Eastern Gulf of Mexico of the OCS. The 

proposed project associated with permit OCS-EPA-R4019 will mobilize the exploratory drillship Diamond 

BlackHawk and the proposed project associated with permit OCS-EPA-R4020 will mobilize the exploratory 

drillship Diamond BlackHornet. The proposed projects are for exploratory drilling and well completion and 

maintenance activities only and do not include the establishment of any permanent production platforms.

The EPA prepared two draft permits for public comment, as well as a preliminary determination/statement of 

basis for each draft permit that explains the permit conditions. The draft permit conditions and preliminary 

determination documents are the same for both projects; they simply reference different drilling rigs. The 

preliminary determinations and the draft permits are available on the EPA Region 4’s website at: 

http://www.epa.gov/region4/air/permits/ocspermits/ocspermits.html and regulations.gov (docket #EPA-R04-

OAR-2014-0728). The permits incorporate applicable requirements from the federal Prevention of Significant 

Deterioration preconstruction and title V operating permit programs, New Source Performance Standards (NSPS), 

and National Emission Standards for Hazardous Air Pollutants (NESHAP), as required by the OCS Air Quality 

Regulations at 40 Code of Federal Regulations (CFR) part 55.

During the public comment period, which commenced on November 14, 2014, and ended on December 15, 2014, 

the EPA only received comments from Anadarko. The EPA did not receive a request for a public hearing and did

not hold a public hearing because it has determined that there was not a significant degree of public interest in the 

permit. The Response to Comments document summarizes the comments received, provides the EPA’s response, 

and summarizes the changes made to the permit. A copy of the comments is in the administrative record for the 

BlackHawk and BlackHornet permits and available at the website listed above. 

In addition, the EPA has clarified the Project Description section of the permit. The EPA removed the reference 

to “facilities on the sea floor” in the description of the well maintenance activities in the Project Description 

section. The EPA removed the reference to “facilities on the sea floor” in the description of the well maintenance 

activities in the Project Description section because there are no facilities on the sea floor associated with the 

permitted well maintenance activities. 

After consideration of the expressed view of all interested persons, the pertinent federal statutes and regulations, 

and additional material relevant to the application and contained in the administrative record, the EPA has made a 

final determination in accordance with title 40 CFR part 55 to issue two air permits to Anadarko for their 

proposed exploratory drilling operation. The final permits do not differ significantly from the draft permits

offered for public comment. 

The final permits, the EPA’s response to the public comments, and additional supporting information are 

available at http://www.epa.gov/region4/air/permits/ocspermits/ocspermits.html. Copies of the final permits and 

the EPA’s responses to the public comments are available for inspection during normal business hours at the EPA 
Response to Comments OCS-EPA-R4019 and - R4020 BlackHawk BlackHornet

Region 4 Office (please contact the EPA in advance for available viewing times) and are also available upon 

request. To request these documents or check available viewing times, please contact Ms. Rosa Yarbrough at: 

R4OCSpermits@epa.gov; (404) 562-9643; or EPA Region 4, APTMD; ATTN: Ms. Rosa Yarbrough, 61 Forsyth 

Street, SW; Atlanta, GA 30303.

Any person who filed comments on the draft permits may petition the Environmental Appeals Board (EAB) 

by January 30, 2015, to review any condition of the final permit. Others may petition for review only with 

respect to any changes from the draft to the final permit decision or other grounds that were not reasonably 

foreseeable during the public comment period on the draft permit. The petition must be filed with the Clerk 

of the EAB no later than January 30, 2015 and contain the information required by 40 CFR §§ 71.11(l) and 

124.19. Please see 40 CFR § 124.19, 40 CFR § 71.11(l), and the EAB’s website at http://www.epa.gov/eab/

for more information regarding the procedure for appeals to the EAB. Please also visit the EAB website for 

filing addresses and electronic filing information.

Please bring this announcement to the attention of all persons who you know would be interested in the 

matter.
Response to Comments OCS-EPA-R4019 and - R4020 BlackHawk BlackHornet

Summary of Comments Received from Anadarko Petroleum Corporation on 

Draft Outer Continental Shelf Air Permits OCS-EPA-R4019 and OCS-EPA-R4020 

Followed by EPA Responses:

Comment 1: Section 5.23 Transfer of Ownership (page 16) - Anadarko commented that this 

condition is not applicable in the offshore context, because it does not reflect the ownership of the 

permit and the drillship for projects on the OCS. Anadarko requested the language of this condition 

change, as reflected by the strikethrough and bold, to the following: 

In the event of any changes in control or ownership of the OCS source, t This permit shall be 

binding on all subsequent owners and operators if the permittee elects to transfer the permit. If 

transferred, the permittee shall notify the succeeding owner and operator of the existence of this 

permit and its conditions by letter, a copy of which shall be forwarded to EPA Region 4 in 

accordance with Condition 5.16.7.

Response: The EPA concurs that this comment does not reflect the mobile nature and ownership of 

OCS drilling vessels. The EPA has revised the condition to reference the requirements of 40 CFR 

71.7(d) for amending a permit to reflect changes in ownership or operational control.

Comment 2: Section 6.6 BlackHawk Emissions and Operating Limits (page 24) - Anadarko 

requested that the emission limits in Condition 6.6.1.1.9 through 6.6.1.1.12 for the main engines be 

changed consistent with previously requested BACT limits. 

Response: Condition 6.6.1.1.9 of the draft permit sets the VOC BACT limit for DR-ME-07 and DRME-08 at 6.2 lb/hr. Anadarko proposed a limit of 9.16 lb/hr in comments on the draft permit and in 

Anadarko’s August 2014 addendum submittal. As stated in EPA’s preliminary determination, the EPA 

used the stack test data in Appendix B of the Emissions Test Report received by the EPA on July 15, 

2014, to set the VOC BACT emission limit for DR-ME-07 and DR-ME-08 in the draft permit. The draft 

permit limit of 6.2 lb/hr was determined based on these stack test results and the 95% confidence 

interval of the highest emitting engine operating at 50% load. Anadarko calculated their proposed limit 

of 9.16 lb/hr by interpolating the stack test data from the smaller engines, DR-ME-01 through 

DR-ME-06, measured at 30% and 60% load.

The EPA concurs that the stack test results for the Hyundai-HiMsen (HHI) engines on the BlackHawk 

drillship represent a small data set upon which to base the emission limitation. However, EPA does not 

find the applicant’s methodology of using interpolated data from the smaller engines to be more reliable 

than actual emissions data from the larger engines operating at the permitted 50% load. Hence, EPA has 

retained the emission limit proposed in the draft permit. Revisions to the permitted limits may be 

necessary as additional operating data becomes available. 

Anadarko proposed PM/PM10/PM2.5 BACT emission limits for DR-ME-01 through DR-ME-08 in their 

comments for Conditions 6.6.1.1.10 through 6.6.1.1.12. The limits requested in Anadarko’s comments 

on the draft permit correspond to Anadarko’s July 18, 2014 submittal, which was subsequently updated 

in Anadarko’s August 2014 submittal. A summary of the July 18, 2014 and the August 2014 limits 

appears on page 2 of the August 2014 addendum submittal. The EPA relied on the PM/PM10/PM2.5
Response to Comments OCS-EPA-R4019 and - R4020 BlackHawk BlackHornet

BACT emission limits for DR-ME-01 through DR-ME-08 proposed in the revised August 2014 

submittal, as well as our independent analysis, to establish the PM/PM10/PM2.5 BACT emission limits 

for these engines in the permits. Anadarko did not provide any new information to substantiate a change 

in these permit limits to reflect those in Anadarko’s July 18, 2014 submittal, and therefore, the EPA

retained the limits as proposed in the draft permit. 

Comment 3: Section 6.6.1.3 Monitoring and Recordkeeping (page 26) - The condition requires the 

permittee to monitor and record NOx, CO, and O2 emissions in ppm. Anadarko commented that the 

monitoring system will record O2 emissions in percentage as opposed to ppm, and requested the 

condition change to reflect this. 

Response: The requested change is consistent with the application and the assumptions used in the 

EPA’s review. The EPA changed the units for O2 as requested to reflect the actual monitoring 

parameters. 

Comment 4: Section 6.6.7 Source Identification: DR-VG-01 through DR-VG-04 (page 32) -

Anadarko requested that greenhouse gas (GHG) limit be updated from the limit proposed in the 

September 2013 application to the limit submitted as part of the February 11, 2014 technical 

memorandum based on EPA’s revised global warming potentials. 

Response: The EPA has included the requested change in the final permit and updated the GHG limit to 

reflect the most recent GHG submittal from February 11, 2014. 

Comment 5: Section 6.7.1 (page 39) - This condition limits the fuel for all support vessels. Anadarko 

requested that the daily and annual fuel limits increase from the worst-case emissions for the supply boat 

to the total worst-case emissions for all support vessels. 

Response: The requested change is consistent with the application and the assumptions used in the 

EPA’s review. This condition limits the support vessels based on the modeling analysis. However, the 

corresponding fuel limit used in the modeling procedure included only the supply and the anchor 

handling boat. Therefore, Condition 6.7.1 has been modified to only apply to the supply and anchor 

handling boats. In addition, the EPA included specific fuel or hourly limits for the stimulation vessel, the 

tug, the barge, and the well evaluation vessel, to more accurately reflect the emissions that were 

modeled and the emission estimates used in the application. These additional operating limits are based 

on the information presented in Anadarko’s August 2014 submittal.

Comment 6: Section 6.11 (page 43) - This condition includes an inaccurate engine reference for the

well evaluation engines, DR-TP-12 through DR-TP-16. Anadarko has proposed that the description DRTP-16 through DR-TP-21 change to accurately reflect the well evaluation units, DR-TP-12 through DRTP-16.

Response: The EPA corrected this inadvertent error as requested. 
Response to Comments OCS-EPA-R4019 and - R4020 BlackHawk BlackHornet

Comment 7: Preliminary Determination and Statement of Basis Section 4.5.1 (page 13) - Anadarko 

requested removing language justifying the EPA’s decision for granting Anadarko an exemption under 

40 CFR part 55. 

Response: The EPA typically does not re-issue the preliminary determination document with the final 

permit nor change our justifications for permit terms that will not be revised. The EPA has determined 

that, based on currently available data, no emissions offsets will be required. If, however, the EPA 

determines that the facility emissions were misrepresented in the permit application, or for other reasons 

of material error, the EPA has the authority to open and revise the permit for cause.