Air Quality Permit proposed to Shell Gulf of Mexico to Operate the
Frontier Discoverer Drillship in the Chukchi Sea, Alaska

PUBLIC COMMENT PERIOD: AUGUST 20 - OCTOBER 5, 2009

The U.S. Environmental Protection Agency (EPA) is seeking public comment on a proposed Clean Air Act
permit for Shell Gulf of Mexico Inc. (Shell), 3601C Street, Suite 1000, Anchorage. Alaska 99503. The proposed
permit will allow Shell to operate the Frontier Discoverer drillship and its fleet for a multi-year exploratory oil
and gas drilling program within its current lease blocks from lease sale 193 on the Chukchi Sea outer continental
shelf (OCS), beyond 25 miles from Alaska's seaward boundary. Because the drillship operations would be a
"major" source, the permit must ensure that the operations meet the requirements of the Prevention of
Significant Deterioration (PSD) program. The proposed permit is also based on non-guideline ISC3-PRIME
modeling system used to predict air pollutant concentrations.

You are invited to comment on the proposed Shell OCS/PSD permit for the Chukchi Sea. You may also
comment on the non-guideline methodology used to determine ambient air quality impacts. You may submit
oral or written comments on the proposed permit at the public hearings. You do not need to attend the public
hearings in order to submit written comments. You may send written comments to the address above. All
comments must be received by EPA by the end of the public comment period October 5, 2009.

Send comments on the proposed permit to:

EPA Region 10

Shell Chukchi OCS Air Permit

1200 6th Ave, Ste. 900, AWT-107

Seattle, Washington 98101

Fax: 206-553-0110

Email: R10ocsairpennits@epa.gov

For questions about the proposed permit,
contact:

Pat Nair, Permit Writer
EPA Region 10
Phone: 208-378-5754
Fax: 208-378-5744
Email: nair.pat@epa.gov

PUBLIC HEARINGS AND INFORMATIONAL MEETINGS

September 23, 2009

North Slope Borough Assembly Room
1689 Okpik Street, Barrow, Alaska
Informational meeting: 3 p.m. - 5 p.m.
Public hearing: 5 p.m. - (end of comments)

September 25, 2009

Loussac Public Library Assembly Chamber
3600 Denali Street, Anchorage, Alaska
Informational meeting: 10 a.m. - 11 a.m.
Public hearing: 11 a.m. - 2 p.m.

Inupiat translation will be available at the meeting and hearing in Barrow. You can also participate in the
public hearing by telephone at the teleconference centers in Atqasuk, Wainwriglit. Point Lay, and Point Hope.

For More Information

Suzanne Skadowski, Community Involvement Coordinator
EPA Region 10, Seattle, Washington
206-553-6689 or toll-free 800-424-4372
Email: skadowski.suzanne@epa. go v
Web: http://vosemite.epa.gov/R10/airoage.nsf/Pennits/chukchiaD

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PERMIT DOCUMENTS AVAILABLE

EPA has prepared a detailed document called a "statement of basis" that explains the derivation of the
proposed permit conditions and the reasons for them. The record for this permit action includes Shell's
application and addendums, all supplemental information submitted by Shell, the statement of basis, the
proposed OCS/PSD permit and all other materials relied on by EPA. The permit application, the statement of
basis for the permit, and the proposed OCS/PSD permit are available at the locations listed below. Please call
in advance for available viewing times.

Barrow City Office, 2022 Ahkovak Street, Barrow, Alaska, 907-852-4050

Wainwright City Office, 1217 Airport Road, Wainwright, Alaska, 907-763-2815

Atqasuk City Office, 5010 Ekosik Street, Atqasuk, Alaska, 907-633-6811

Kali School Library, 1029 Ugrak Ave, Point Lay, Alaska, 907-833-2312

Point Hope City Office, 530 Natchiq Street, Point Hope, Alaska, 907-368-2537

EPA Alaska Office, Federal Building, 222 West 7th Ave, Anchorage, Alaska, 907-271-5083

The permit application, statement of basis, proposed permit and a permit information sheet are also available
on the web at: http://vosemite.epa.gov/R10/airpage.nsf/Permits/chukcliiap. The permit record is available at
the EPA Region 10 Library, 1200 6th Ave, Seattle, Washington, 206-553-1259. To request a copy of these
materials or a copy of the permit record, contact Suzanne Skadowski as described above.

Any interested person may submit written comments on the proposed permit during the public comment
period. If you believe any condition of this permit is inappropriate, you must raise all reasonably
ascertainable issues and submit all reasonably available arguments supporting your position by the end of the
comment period. Any documents supporting your comments must be included in full and may not be
incorporated by reference unless they are already part of the record for this permit or consist of state or
federal statutes or regulations, EPA documents of general applicability, or other generally available
referenced materials. These proceedings are subject to the requirements of 40 C.F.R. Part 124.

All timely comments will be considered in making the final decision, included in the record, and responded to
by EPA. EPA will prepare a statement of reasons for changes made in the final permit and a response to
comments received and will provide all commenters with notice of the final permit decision.

INFORMATION ABOUT THE PROPOSED PERMIT
Sources of Air Emissions

The Discoverer is a turret-moored drillsliip with air emission sources that include generators for the drilling
systems and associated self-powered equipment (such as air compressors, hydraulic pumps, cranes, boilers
and other small sources), small boilers for heating and a small incinerator. The Discoverer's operations at an
exploratory drill site will be supported by an associated fleet that consist of a primary icebreaker, a secondary
icebreaker, a supply ship, an oil spill response ship, and oil spill workboats. The supply ship will make up to
eight trips a year from Wainwright or Barrow to the Discoverer. As provided in the OCS regulations,
emissions from a support vessel are counted as emissions from the OCS source when the Discoverer is
anchored at a drill site and the support vessel is within 25 miles of the Discoverer.

The main pollutants that will be emitted from the Discoverer and its support vessels are nitrogen oxides
(NOx), sulfur dioxide (S02), particulate matter (PM, PM10, and PM2.5), carbon monoxide (CO), and volatile
organic compounds (VOC).

Air Pollution Controls

The proposed OCS/PSD permit requires Best Available Control Technology (BACT) on the Discoverer, to
limit emissions of air pollutants while the Discoverer is anchored at a drill site. Control measures on the
Discoverer include the use of ultra-low sulfur diesel fuel to reduce emissions of S02, Selective Catalytic
Reduction controls and an oxidation catalyst on the six largest engines to reduce emissions of NOx, and
catalyzed diesel particulate filters on all smaller, older engines to limit emissions of VOC, CO, and particulate

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matter (PM, PM10, and PM2.5). The proposed permit also requires the use of good operation and
maintenance procedures and good combustion practices on the Discoverer and the support vessels to ensure
emission limits are met. The permit also requires record-keeping and reporting necessary to determine
compliance with the permit terms and conditions.

Air Quality Demonstration

As part of the permit application process. Shell is required to use air quality monitoring information and
modeling to demonstrate that air quality in the vicinity of their drilling operations in the Chukchi Sea will
continue to meet the National Ambient Air Quality Standards and PSD increments.

In addition to emission limitations and permit requirements that impose BACT, the proposed Shell OCS/PSD
permit also includes annual emission limits for NOx, daily emission limits for PM10 and PM2.5, and other
operational restrictions to ensure that emissions from the Discoverer and its support vessels do not exceed the
National Ambient Air Quality Standards or PSD increments while the Discoverer is anchored at a drill site.
Examples of operational restrictions include: a limit on drilling to a total of 168 days between July 1 and
December 31 of each year, and limits on the amount of fuel that can be combusted.

The proposed permit is based on the non-guideline ISC3 -PRIME modeling system used to predict air
pollutant concentrations. This modeling system has not been approved by the EPA for general use, but has
been tested for use in arctic conditions. PSD increments are limits on the amount that air quality can be
degraded by actual emissions. The following percentages of the applicable PSD increments are predicted to
be consumed by Shell's operations: 3-hour Sulfur Dioxide (S02): 14.45 %; 24-hour S02: 30.77%; annual
S02: 10.50%; annual Nitrogen Dioxide (N02): 83.20%; 24-hour Particulate Matter Less than 10 (PM10):
94.00%; and annual PM10 11.18%.

The proposed permit, if effective, would allow the Discoverer and the support vessels to emit air pollutants as
specified in Table 1.

Table 1 - Permitted Air Pollutant Emissions from Discoverer and Associated Fleet as OCS Source at all Locations

Air Pollutant

Emissions



(tons per year)

Carbon Monoxide

762

Nitrogen Oxides (NOx)

1965

Particulate Matter Less than 2.5 (PM2.5)

184

Particulate Matter Less than 10 (PM10)

210

Particulate Matter

260

Sulfur Dioxide (S02)

181

Volatile Organic Compounds (VOC)

166

Additional Project Information

EPA Region 10 has also received five notices of intent from Shell requesting authorization for coverage
under the Arctic General Permit (AKG-28-0000) for exploration activities in its current leases blocks from
lease sale 193 within the Chukchi Sea. Shell's notices of intent and information about the Arctic General
Permit are available at: http://vosemite.epa.gov/RlOAVATER.NSF/NPDES+Permits/General+NPDES+Permits.

Mailing List

If you would like to be added to our mailing list to receive future information about this air permit or other
EPA permits in the Chukchi and Beaufort Seas, contact:

Suzanne Skadowski, Community Involvement Coordinator
EPA Region 10, Seattle, Washington
206-553-6689 or toll-free 800-424-4372
Email: skadowski.suzanne@epa.gov

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