NC0000795_Permit Modification_20030423

NPDES DOCUHENT SCANNING COVER SHEET
NPDES Permit:
NC0000795
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Permit
History
Document Date:
April 23, 2003
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NCDENR
Mr. Barry L. Furr
Terminal Superintendent
ExxonMobil Refining & Supply Company
Post Office Box 18363
Greensboro, North Carolina 27419
Dear Mr. Furr:
Michael F. Easley
Governor
William G. Ross, Jr., Secretary
North Carolina Department of Environment and Natural Resources
Alan W. Klimek, P.E., Director
Division of Water Quality
April 23, 2003
Subject: Modification of NPDES Permit NC0000795
ExxonMobil Greensboro Terminal
Guilford County
The Division received your request to modify the subject permit on April 2, 2003. A review of the permit
condition you referenced noted that no due date was specified for the MTBE reduction plan. Your facility has also
not yet collected 12 MTBE samples. The Division is therefore granting your request to extend the sampling period.
This permit modification specifies the date by which the MTBE reduction plan must be submitted to the Division.
Please find enclosed the revised page, which should be inserted into your permit. The old page may then be
discarded. All other terms and conditions contained in the original permit remain unchanged and in full effect. This
permit modification is issued under the requirements of North Carolina General Statutes 143-215.1 and the
Memorandum of Agreement between North Carolina and the U.S. Environmental Protection Agency.
If any parts, measurement frequencies or sampling requirements contained in this permit modification are
unacceptable to you, you have the right to an adjudicatory hearing upon written request within thirty (30) days
following receipt of this letter. This request must be a written petition conforming to Chapter 150B of the North
Carolina General Statutes, filed with the Office of Administrative Hearings (6714 Mail Service Center, Raleigh, North
Carolina 27699-6714). Unless such demand is made, this decision shall be final and binding.
If you have any questions concerning this permit modification, please contact Charles Weaver of the NPDES
Unit at [phone], extension 511.
cc: Central Files
Winston-Salem Regional Office, Water Quality Section
NPDES Unit
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Sincerely,
tt.ihr)
an W. Klimek, P.E.
Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer Visir us ON THE irirERNEr @ http://h2o.enr.state.nc.us/NPDES

Permit NC0000795
EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
SPECIAL CONDITIONS
A. (2.) MTBE MONITORING
For the protection of public health, oil terminals discharging to waters classified as water supplies
("WS" waters) shall adhere to the following action plan:
1. Monthly monitoring for MTBE (except as modified under 2.) is required for the duration
of the permit [See Part A. (1.)].
2. After a one-year Test Period of monthly monitoring or after twelve (12) discharge events
have been sampled and analyzed, the Permittee shall review MTBE data. If MTBE is not
detected, the facility may request the Division to reduce the MTBE monitoring
frequency. Granting this request shall constitute a minor modification to the NPDES
permit.
3. If MTBE is detected during the Test Period, the Permittee shall submit an MTBE
Reduction Plan. This plan may include site -specific Best Management Practices (BMPs)
or engineering solutions. A copy of this plan shall be submitted to:
North Carolina Division of Water Quality
Water Quality Section
Attn: NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
4. The Division anticipates that an MTBE regulatory criterion or Water Quality Standard
will be established during the coming permit cycle. For the next cycle of permit renewals,
the Division expects to apply this criterion or standard to MTBE data collected during
this permit cycle. Should the permittee's MTBE data indicate discharge in excess of this
criterion or Water Quality Standard, an MTBE limit will be added to the permit
monitoring requirements at renewal.
5. The permittee shall submit the MTBE reduction plan no later than May 1, 2004.

ExxonMobil
Refining & Supply Company
Post Office Box 18363
Chrmiao26.N2tibgarolina 27419
North Carolina Division of Water Quality
Water Quality Section
Attn: NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
RE: ExxonMobil Greensboro Terminal
NPDES Permit No.: NC0000795
MTBE Data Review
Dear NPDES Contact,
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E(onMobil
Refining & Supply
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In accordance with Section A.(2)., MTBE Special Condition, of ExxonMobil Greensboro Terminal's
NPDES Permit No. NC0000795, a review of monthly monitoring data for MTBE has been conducted
and is summarized on the attached table. As can be seen from the data, since this permit became
effective in February 2003, the Greensboro Terminal has experience six discharges. Five of the MTBE
sample results were "Non -detect". One sample result indicated the presence of MTBE, but at a
concentration of 1.2 ug/I, which is only slightly above the. test detection limit of 1.0 ug/I.
The presence of MTBE in the December 2002 discharge has since been followed by a February 2003
"Non -detect" discharge sample result. (There was no stormwater discharge in January 2003). We have
inspected our site, reviewed our facilities and our operations and have not been able to identify an
apparent reason for the presence of MTBE in the sample results reported by the lab. Though a
laboratory error is unlikely, it cannot be ruled out.
Since the reported presence of MTBE in the discharge sample appears to be an isolated event and,
perhaps, may be the results of an analytical anomaly; we believe more data is needed before initiating
measures beyond those already in place to address reported MTBE in stormwater discharges.
Accordingly, we respectfully request that the requirement to submit a MTBE reduction plan be deferred
for one additional year. During this additional time, discharges will continue to be monitored monthly
and reviewed for the presence of MTBE. It is proposed that if MTBE is detected during this additional
one-year test period, the ExxonMobil Greensboro Terminal will then develop and submit to the Division
an MTBE Reduction Plan as described in permit condition A.(2.)3. Also. if no MTBE is detected during
the additional test period, the terminal may request the Division to reduce the MTBE monitoring
frequency.
Given the isolated and unclear basis for the report of the detection of a small amount of MTBE in one of
Greensboro Terminal's discharge samples, we believe the above request to be a reasonable and
prudent approach. We trust you will agree with the above and approve the conditions outlined above.
Thank you very much for your consideration of this matter. If you have any questions or comments,
please contact me at 336-855-4460.
Sincerely,
Barry tr. urr
Terminal Superintendent