2022.03.28_CCO.p.18_COPY_DEQ Response letter re LCFR Assessment

March 28, 2022

Ms. Dawn Hughes
Plant Manager
Chemours Fayetteville Works
22828 NC Highway 87 W
Fayetteville NC 28306

RE: Notice Regarding Chemours’ Obligations Under the Consent Order and 15A NCAC
02L .0106 - Offsite Groundwater Assessment and Provision of Replacement Drinking Water
Supplies.

Dear Ms. Hughes:

The North Carolina Department of Environmental Quality (DEQ) has reviewed the February 1,
2022 documents from Chemours in response to our November 3, 2021 Notice Regarding
Chemours’ Obligations Under the Consent Order and 15A NCAC 02L .0106 - Offsite
Groundwater Assessment and Provision of Replacement Drinking Water Supplies. These
documents included a cover letter, the Framework to Assess Table 3+ PFAS in New Hanover,
Brunswick, Columbus, and Pender Counties, and the Interim Four Counties Sampling and
Drinking Water Plan. DEQ has also received and reviewed the Chemours’ March 4, 2022
response letter to DEQ’s response to Chemours’ February 1 submittal titled Interim Four
Counties Sampling and Drinking Water Plan.
Within this letter DEQ has provided a response to the March 4th letter from Chemours and
comments on the Framework to Assess Table 3+ PFAS in New Hanover, Brunswick, Columbus,
and Pender Counties as presented by Chemours.

Public Records Requests
Chemours has requested DEQ to make available additional data per the November 2021 public
records request to inform its development and implementation of the two plans. DEQ has
provided all data within our possession that is responsive to your public records request. Much
of that data is publicly accessible through the DEQ website. DEQ staff have previously
communicated to you that the communications portion of your request (such as DEQ emails) is
still in process and may take longer to complete. Although we intend to fulfill that portion of
your request, we do not anticipate that the communications contain necessary data and material

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information that we have not previously provided. Any data collected and analyzed in the future
for the four lower Cape Fear county areas will be publicly posted at the following site: GenX
Investigation | NC DEQ.

Chemours has also requested that DEQ facilitate the receipt of requested information from the
four counties. DEQ has communicated and encouraged the appropriate local government entities
to provide available data and relevant information.

Offsite Groundwater Assessment
DEQ finds the document for the Framework to Assess Table 3+ PFAS in New Hanover,
Brunswick, Columbus and Pender Counties Sampling and Drinking Water Plan requires
an expanded scope and additional detail to fulfill the requirements of Paragraph 18 of the
Consent Order and North Carolina’s groundwater rules.

DEQ’s November 3rd letter noted that Chemours is responsible for contamination of groundwater
wells and water supply wells in New Hanover County and potentially downstream counties
affected by PFAS contamination in the Cape Fear River. Pursuant to paragraph 18 of the Consent
Order, Chemours must conduct a comprehensive assessment of this contamination and ultimately
prepare an appropriate corrective action plan to address it.

Within 45 days of receipt of this letter, Chemours must submit a revised Framework to Assess
PFAS in groundwater in New Hanover, Brunswick, Columbus and Pender Counties addressing
the following comments:

1. The hypotheses presented by Chemours that may have led to groundwater contamination
in the region are based on limited data sets and require revision. The current hypothesis
list in this document is not comprehensive, and additional hypotheses may need to be
added later based on data and other information gathered. For example, there is no data
or hypothesis based on the PFAS that would have been in historical process wastewater
released into the Cape Fear River from 1979-2010, before the facility changed to
manufacturing GenX and other Chemours products. The revised Framework should also
propose a process for identifying unknown leaks from the water distribution and sanitary
sewer collection network, and should include background samples, not just upgradient
samples, as the area of impact from water and sewer system leaks is not yet known.

2. There is also insufficient data to rule out pathways such as atmospheric transport and
deposition with the current data set. The potential for chemical transformation of
precursor PFAS in areas further from the facility should also be considered. Further data
collection and modeling of air emissions before the installation of pollution controls are
required before ruling out this hypothesis.

3. The timeline presented to commence data gathering over a six-month timeframe is far too
long before gathering actual assessment data. We believe sufficient information is
currently available to proceed with assessments. This timeframe for data gathering shall
be reduced to two months from the date of this letter based on the notice DEQ provided

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to Chemours in November of 2021. As noted previously by DEQ, private well sampling
results are not sufficient to fully assess groundwater impacts.

4. Samples of all media shall be representative of the four county region identified. The
current plan describes selecting only four locations where leaking utility pipes may be a
factor along with two locations representing areas of direct injection or application of
Cape Fear River water and two locations of aquifer recharge by the Cape Fear River.
These sample numbers are not representative of the four-county region. It is our
understanding that Chemours has received voluminous information including maps and
data on distribution and collection systems from at least some of the four counties. We
encourage Chemours to fully examine this information and discuss with county officials
the methods through which contamination may have dispersed in their respective regions,
then move forward with detailed planning and representative sampling. The revised
Framework should propose increased and statistically significant representative sampling
to identify (1) areas where leaking utility pipes may be a factor; (2) areas of direct
injection or application of Cape Fear River water; and (3) areas of aquifer recharge by the
Cape Fear River. Such representative sampling will provide a more robust dataset for
informed decision making moving forward.

5. Sample analysis should include Table 3+ PFAS and all Method 537.1 PFAS, to
determine areas impacted by both current and historic releases from the facility and areas
where there are other potential sources. Analytical methods must be able to quantify
detections in both groundwater and soil at appropriate levels to identify areas of impact.

Interim Four Counties Sampling and Drinking Water Plan
In addition to the seven items identified in DEQ’s March 2, 2022 letter, Chemours shall expand
eligibility criteria to include wells near tributaries to the Cape Fear River, floodplains, and areas
where PFAS may have seeped into surrounding aquifers (such as areas of leaking utility pipes or
direct injection of Cape Fear River water).

We appreciate your attention and prompt response in this matter. If you have any questions,
please feel free to contact me at [phone].

Sincerely,

Sushma Masemore, P.E.
Assistant Secretary for the Environment