DEQ-CFW_00061180

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DuPont Fluoroproducts
Ms. Belinda S. Henson
Surface Water Protection Supervisor
NCDENR — Water Quality Programs
225 Green Street — Suite 714
Fayetteville, NC 28301-5095
DENR-FRO
JAN 31 20%
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DuPont Fluoroproducts
22828 NC Highway 87 W
Fayetteville, NC 28306-7332
January 30, 2014
SUBJECT: Written Report of Ethylene Glycol Release to Wastewater Treatment Plant
NPDES Wastewater Discharge Permit No. NC0003573
DuPont Company — Fayetteville Works
Bladen County, North Carolina
Dear Ms. Henson:
At 7:30 p.m. on January 26, 2014, an overflow of an ethylene glycol based heat -transfer liquid
from a tank in the DuPont Company — Fayetteville Works ("DuPont") Butacite® Manufacturing
Facility resulted in 3,400 lb. of ethylene glycol being sent to the DuPont wastewater treatment
plant ("WWTP").
This occurrence could potentially qualify as a "discharge of significant amounts of wastes which
are abnormal in... characteristic, such as... the known passage of a slug of hazardous substance
through the facility" as described in Part I1 Section E(9)(a) of the subject permit.
Therefore, to comply with the requirement of Section E(9)(a) of the permit, DuPont reported the
above occurrence by telephone to the N.C. Division of Water Resources' Fayetteville Regional
Office on January 27, 2014.
Section E(9) of the permit requires that DuPont "also file a written report within 5 days
following first knowledge of the occurrence." This letter is the required written report.
A hydraulic model of the DuPont WWTP system shows that an instantaneous introduction of
3,400 pounds of ethylene glycol into the Equalization Basin would result in a maximum
concentration of 110 mg/L at Outfall 001 forty hours later, assuming no biodegradation. This
equates to 0.22 mg/L in the Cape Fear River at the 7Q 10 low flow rate of 791 cubic feet per
second ("cfs") and 0.06 mg/L in the Cape Fear River at the actual flow rate of 3,000 cfs.
E. I. du Pont de Nemours and Company FL-4 Rev. 3/2000
DEQ-CFW 00061180

Ms. Belinda S. Henson
Page 2 of 2
NCDENR — Water Quality Programs
January 30, 2014
Per the EPA Integrated Risk Information System ("IRIS") database, the oral reference dose
("Rf)") for ethylene glycol is 2 mg/kg/day. Using the standard 2 L/day of consumed water for a
70 kg adult, that Rf) equates to a concentration of 70 mg/L in a drinking water source "that is
likely to be without an appreciable risk of deleterious effects during a lifetime."
Therefore, using the above worst -case scenario, the resulting concentration of ethylene glycol in
the river (0.22 mg/L at the 7Q10 low flow rate) is 300 times lower than the No Observed Effect
Level (70 mg/L) for the oral consumption of ethylene glycol.
It is likely that some portion of the ethylene glycol would be degraded as part of the normal
operation of the WWTP biological treatment, therefore the actual discharge of the compound to
the river would be a fraction of the values reported in this letter.
If you should have any questions about this report or if you need additional information, feel free
to call me at [phone].
Environmental Manager
DEQ-CFW 00061181