NC0000795_Permit Modification_19961216

NPDES DOCUMENT 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:
December 16, 1996
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State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governor
Jonathan B. Howes, Secretary
A. Preston Howard, Jr., P.E., Director
Mr. Michael Slemp
Exxon Company, U.S.A.
P.O. Box 30451
Charlotte, North Carolina 28230
December 16, 1996
Subject: Permit Modification
NPDES Permit NC0000795
Exxon Products Terminal #4187
Guilford County
Dear Mr. Slemp:
As you may be aware, the public in the Paw Creek area near Charlotte is very concerned with
any activities associated with the oil terminals (including renewal of NPDES permits). The Division
held a public hearing on May 16, 1996, for the renewal of several oil terminal NPDES permits in the
Paw Creek area. Many people attended the hearing and the Division received numerous comments at
the hearing and during the public comment period. As a result of these comments, the Division re-
examined and researched several issues, including chlorophenols. Chlorophenols required a more
extensive research effort than other issues raised during the public comment period. This letter
documents and summarizes changes to chlorophenols requirements in your permit, and also addresses
some other changes to the permit which reflect concerns raised by the public.
It should be noted that changes to permits pertain to facilities that discharge to water -supply
classified waters only. Permits will not change for facilities discharging to non -water -supply waters.
In response to comments pertaining to the chlorophenol monitoring requirements in the draft
permits, the Division re -investigated the following two questions: (1) Why was there a requirement to
monitor for eight individual chlorophenols in addition to those specified in EPA Method 625; and (2)
What is the proper laboratory procedure to analyze for these eight chlorophenols?
After some additional research and discussion, two determinations were made. First, although
all chlorophenols have the potential to cause taste and odor problems in drinking water supplies and
tainting of fish tissue, the eight chlorophenols not covered by EPA Method 625 (and singled out for
individual monitoring in the permit) are not considered to be carcinogens. Second, when phenol is
exposed to chlorine, certain chlorophenols form before others. This is significant because a few key
"early -forming" chlorophenols can be used to "screen" the stormwater discharge for the presence of
chlorophenols. Specifically, the five chlorophenols included in EPA Method 625 can be used as
indicators of all chlorophenols because these five compounds would be the first to form when chlorine
reacts with phenol.
Therefore, EPA Method 625 will be used as an initial screen. If no chlorophenols are detected,
no additional monitoring will be required. However, if one or more chlorophenols are detected at
concentrations greater than 50 µg/1, then the oil terminal would be required to monitor for the eight
additional chlorophenols beginning with the next scheduled monitoring event and continue to monitor
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone] FAX [phone]
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semi-annually until the permit expired. The additional chlorophenol monitoring would include
identifying and quantifying all chlorophenols present in the sample(s).
Although the chlorophenol monitoring requirement change was the most significant, another
concern raised by the public pertained to xylene monitoring. Several members of the public noticed that
xylene monitoring was not required in the draft permits. Xylene is not included in EPA Methods 624/625
and therefore, the Division acknowledges that xylene monitoring should and will be included in the oil
terminals' final NPDES permits.
Please find enclosed the modified section of the permit referenced in the preceding paragraphs.
Replace the original sections in your permit with the newer enclosed sections and discard the original
sections. All other terms and conditions contained in the original permit remain unchanged and in full
effect. These permit modifications are issued pursuant to 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 in the form of a
written petition, conforming to Chapter 150B of the North Carolina General Statutes, an filed with the
Office of Administrative Hearings, Post Office Drawer 27447, Raleigh, North Carolina 27611-7447.
Unless such demand is made this decision shall be final and binding.
If you have any questions, please contact Charles Weaver at [phone] extension 511.
Sincerely,
Preston Howard,
cc: Central Files
Winston-Salem Regional Office, Water Quality Section
Roosevelt Childress, EPA
Permits and Engineering Unit
Facility Assessment Unit
Aquatic Survey and Toxicology Unit

A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS - FINAL
Permit No. NC0000795
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is authorized to discharge stormwater and
washdown water from outfall serial number 001. Such discharges shall be limited and monitored by the Permittee as specified below:
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FIow1
Monthly
1
Effluent
Total Suspended Solids
45.0 mg/I
Monthly
Grab
Effluent
Oil and Grease2
Monthly
Grab
Effluent
Phenol
Monthly
Grab
Effluent
Benzene
Monthly
Grab
Effluent
Xylene
Semi-annually
Grab
Effluent
EPA Methods 624/6253
Semi-annually
Grab
Effluent
Acute Toxicity4
4
Grab
Effluent
Footnotes:
1 Where no measurable discharge occurs, "no discharge" should be clearly noted on the submitted monthly discharge monitoring report. Flow is measured
using a flow meter at this facility.
2 Where possible, the grab sample for oil and grease should be skimmed from the surface of a quiescent (calm water) zone.
3 EPA Method 625 includes five (5) chlorophenols. If one or more chlorophenol(s) is detected at concentrations greater than or equal to 501tg/1, the
permittee will be required to analyze for the eight chlorophenols listed below in addition to EPA Method 625. This additional required monitoringwill
begin with the permittee's next scheduled monitoring event, occur on a semi-annual basis and will last for the duration of the permit. Eight
chlorophenols include the following: 3-chlorophenol; 4-chlorophenol; 2,3-dichlorophenol; 2,5-dichlorophenol; 2,6-dichlorophenol; 3,4-
dichlorophenol; 2,3,4,6-tetrachlorophenol and 3-methyl-6-chlorophenol.
4 Acute Toxicity (Fathead Minnow 24 hour) Monitoring: see Part III, Condition E.
There shall be no discharge of floating solids or visible foam in other than trace amounts.
There shall be no direct discharge of tank solids, tank bottom water or the off -specification product.
There shall be no direct discharge of tank contents following hydrostatic testing unless benzene concentration is less than 1.19
µg / 1 and toluene concentration is less than 11

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