2019.06.10_CCO.p11_SubmissionPursuantToConsentOrderSamplingData

The Chemours Company
Fayetteville Works
22828 NC Highway 87 W
Fayetteville, NC 28306

June 10, 2019

Linda Culpepper
Interim Director, Division of Water Resources
1611 Mail Service Center
Raleigh, NC 27699-1611
[e-mail]

Re: Submission Pursuant to Consent Order Paragraph 11

Dear Ms. Culpepper,

Under Paragraph 11 of the Consent Order, Chemours is required to perform certain
PFAS-related sampling at the Fayetteville Works facility under DEQ approved plans and, once
approved, provide quarterly reports to DEQ identifying PFAS constituents and initial
concentrations at any level above the practical quantitation limit in all process and non-process
wastewater and stormwater at the facility, including Outfall 002. Such plans have been
submitted but not been approved to date. Chemours also conducts other PFAS-related sampling
at the facility. Paragraph 11(e) includes a duty to disclose any previously undisclosed PFAS and
its concentrations in process and non-process wastewater and stormwater.

In April and May, Chemours (internal lab) and TestAmerica (external lab) began
analyzing samples obtained from Outfall 002 for certain PFAS compounds for which analytical
methods did not previously exist. These compounds include C4 or smaller compounds such as
DFSA (which is a C2) and the others listed below that are quite difficult to quantify.

Acronym Name Molecular
Formula
CASN Chemical Structure
MTP Perfluoro-2-
methoxypropanoic
acid
CH3-O-
CF2-CF2-
COOH
93449-
21-9

2
MMF Difluoromalonic
acid
HOOC-
CF2-
COOH
743478-
63-9
DFSA Difluoro-sulfo-
acetic acid
HOOC-
CF2-
SO3H
422-67-
3

PPF Acid Perfluoropropionic
acid
CF3-CF2-
COOH
422-64-
0

The first round of results from TestAmerica, which reflect the results of 3.5 day of
composite sampling, are enclosed herein. These results indicate that some of these PFAS
compounds have concentrations in excess of the applicable detection limits, including one of the
newly-detected compounds, DFSA. DFSA was reported by TestAmerica in one 3.5 day
composite sample for the period ending on May 7 at a concentration of 80 ppb with a detection
limit of 3.1 ppb. The subsequent 3.5 day composites, for the periods ending on May 9, May 14
and May 17, were reported, respectively, by TestAmerica at 6.9 ppb for the first sample and then
non-detect for the next two.

Both Chemours and Test America have reason to believe that the 80 ppb quantification
may not be accurate, for several reasons. First, Chemours’ internal laboratory analysis of grab
samples from the same period shows orders of magnitude lower results, with non-detects at a
detection limit of 100 ppt on May 3 and 9, and a detection of 269 parts ppt, which would be non-
detectable under TestAmerica’s methodology, on May 7. Second, Chemours’ process water
continues to be segregated for off-site disposal, and we are not presently aware of any operating
condition or upset that could have caused DFSA to be present at the level reported for the May
7th sample. Further, the analytical chemists we have consulted have told us that C4 or smaller
compounds such as DFSA and others listed above are quite difficult to quantify, and both
TestAmerica and Chemours are working to refine the appropriate testing methodology.
TestAmerica has described some of these testing challenges in a brief technical memorandum,
which is enclosed. Chemours will continue to work with TestAmerica to improve its
methodology for quantifying DFSA, as well as exploring other possible explanations for these
DFSA testing results.

Please let me know if you have any questions.

3
Sincerely,

Brian D. Long
Plant Manager
Chemours – Fayetteville Works

Enclosures
Outfall 002 Data
TestAmerica Technical Memorandum

Cc:
Sheila Holman, DEQ
William F. Lane, DEQ
Francisco Benzoni, NC DOJ
Michael Abraczinskas, DAQ
Michael Scott, DWM
David C. Shelton, Chemours
John F. Savarese, WLRK
Kemp Burdette, CFRW
Geoff Gisler, SELC