2022.04.01_CCO.p.18_Cover Letter Chemours Response to NCDEQ Comments

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

April 1, 2022
Sushma Masemore
Assistant Secretary
N.C. Department of Environmental Quality
1601 Mail Service Center
Raleigh, NC 27699-1601
[e-mail]

Re: Response to DEQ Letter, “Notice Regarding Chemours’ Obligations Under Consent
Order and 15A NCAC 02L .0106 - Offsite Groundwater Assessment and Provision of
Replacement Drinking Water Supplies.”
Dear Ms. Masemore,
This is in further response to your March 2nd letter containing comments from the North Carolina
Department of Environmental Quality (DEQ) on the Interim Four Counties Sampling and
Drinking Water Plan (New Hanover, Brunswick, Columbus and Pender Counties) (the Interim
Plan) prepared by Geosyntec Consultants of NC, P.C. (Geosyntec) and submitted by Chemours
to DEQ on February 1, 2022.1 This letter responds to the seven comments in your letter dated
March 2nd and one additional comment in the March 28th letter, and we are also attaching a
revised Interim Plan incorporating those responses.

Before turning to your comments, we think it is useful to review the status of Chemours’
outreach and assessment efforts in these four counties. On November 3, 2021, DEQ raised with
us for the first time concerns relating to PFAS originating from the Fayetteville Works site in
private drinking water wells in the four counties. These concerns were based on a limited
number of groundwater samples from just one of the counties, New Hanover, some of which
samples were close to three years old. You did not provide then, and we are not aware of now,
any sampling showing presence of such PFAS in private drinking water wells in the other three
counties.

Chemours promptly committed to developing a plan to assess the extent of, and responsibly
address, any such PFAS contamination in private drinking water wells in the four counties. The
Interim Plan submitted on February 1, and the associated Framework to Assess Table 3+ PFAS,
was responsive to the concerns you had raised, and each provides information that informs the
other for making the assessment and sampling and addressing private drinking water well
concerns. Without waiting for DEQ’s comments on the two submittals, Chemours began

1 For purposes of this submission, as similarly noted in my letter accompanying the February 1 submissions,
Chemours is not disputing that paragraph 24 of the Consent Order and related paragraphs apply to private wells in
the four counties but reserves its ability to raise such matter.

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sampling at the request of property owners and residents with wells that met broad eligibility
criteria. To date, of the 66 requests we have received for sampling, 56 met the eligibility criteria
and have been sampled. Of the 26 samples for which we have received analytical results, 23
showed no detections of any of the Fayetteville Works-associated Attachment C PFAS
compounds. Three samples show detections of Attachment C compounds, two of which exceed
the 10 parts per trillion action level set forth in the Consent Order (CO) for one compound,
which is not a health-based level. The residents using those wells are now receiving bottled
water from Chemours. Of course, we recognize that far more extensive sampling will be
necessary before any overall conclusions can be reached and to that end, we are submitting a
revised Interim Plan that addresses each of your comments, as follows:

1. Chemours must expand the eligibility criteria in Section 2.1.3 to include private wells located
in the vicinity of areas of direct application or injection of river water and private wells in
the vicinity of areas where existing data shows the presence of PFAS associated with the
Fayetteville Works facility. In addition, it is recommended that the eligibility criteria be
expanded to include private wells in the vicinity of tributaries to the Cape Fear River and in
floodplains.
The eligibility criteria have been modified in the revised Interim Plan to account for the
following (see Section 2.1.1 in the revised Interim Plan):
a) Private wells located in the vicinity of areas of direct application or injection of river
water.
Chemours agrees to adding this eligibility criteria. Areas where river water was directly
injected or applied to the ground in the vicinity of private wells is uncertain. Based on the
data currently available, Chemours has identified two groundwater injection areas from
Cape Fear Public Utility Authority (CFPUA) and Brunswick County aquifer storage and
recovery (ASR) programs. Other areas of direct application of river water, for example
irrigation uses, may be located within the public water distribution areas and captured by
the current sampling eligibility criteria.
If additional areas of direct river water application or river water injection outside of the
present areas of eligibility are identified during the data gathering step (as indicated in
both the Interim Plan and the Assessment Framework), then the eligibility criteria will be
revised to include these areas.
b) Private wells in the vicinity of areas where existing data shows the presence of PFAS
associated with the Fayetteville Works facility.
The eligibility criteria have been specifically modified to include addresses within a
quarter mile radius of exceedances of CO criteria (private and non-private wells). To
date, PFAS data have been received from private and non-private wells in New Hanover
County and one non-private well in Brunswick County. At the current stage of the data
gathering step, there is very limited to no PFAS analytical data for private and non-
private wells in Brunswick, Columbus and Pender Counties.
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c) Private wells in the vicinity of tributaries to the Cape Fear River and in floodplains.
In the initial Interim Plan (dated February 1, 2022), this criterion was defined as half a
mile from the Cape Fear River which included some tributaries and a majority of the
floodplains.
The revised eligibility criterion will be defined by the extent of the 100-year floodplain
associated with Cape Fear River (provided by the Federal Emergency Management
Agency; FEMA), and will also include the limits of saltwater marshes in the areas where
Black River and Northeast Cape Fear River meet Cape Fear River to account for the
possibility of tidal backwash of Cape Fear River Water into these rivers. Tributaries of
the Cape Fear River empty into the river rather than receive water from the river, and
therefore are not included in the revised criterion. However, as some minor degree of
water interchange may occur during flooding events, the criterion has been revised to
include the last half mile floodplain of each tributary before it joins the Cape Fear River.
2. Chemours must expand sampling conducted under Step 1A to include sampling of a
representative group of private wells in each county that meet the eligibility criteria in
Section 2.1.3 as modified that is not limited to individuals who have requested sampling. The
revised Interim Plan must provide Chemours’ rationale for determining which private wells
to include in the representative sampling. Such representative sampling shall be commenced
within 45 days of receipt of this letter. Representative sampling shall not be limited to 200
private wells in each county. Instead, Chemours should take a data-driven approach that
aims to identify a representative population upon which to base further sampling efforts.
DEQ may require expanded representative sampling if it determines that Chemours’
proposal is insufficient.
Chemours agrees that a data-driven approach is favorable, and the systematic sampling
presented in the initial Interim Plan (dated February 1, 2022) was developed to collect
information that would support this approach. To fulfill a data-driven approach, Chemours
has also requested information from DEQ, the counties and various utilities to request the
required information. Presently, receipt of information requested is ongoing, and only partial
responses have been received to date. Specifically, Chemours has received public water
addresses for the water distribution systems operated by Brunswick County and some areas
of New Hanover County serviced by CFPUA; however, public water information for the
other utilities in Brunswick County and New Hanover County, and for Columbus County and
Pender County is still pending. This information is essential for the design and
implementation of a robust data-driven representative sampling program.
The Interim Plan has been revised to address DEQ’s comments regarding representative
sampling. Based on the data currently available, Chemours is proposing the following
approach, which will be implemented concurrently with the data gathering stage:
• Contact by mail properties that are located within the areas of the modified sampling
criteria (see response to comment #1 and Section 2.1.1 of revised Interim Plan).
These letters will request well owners/residents to provide a response on whether they
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are connected to public water (if the status of public water connection is unknown)
and if their primary source of drinking water is a private well and will offer sampling
of their private well. Letters will not be sent to owners/residents that are known to be
connected to public water.
• Once the well owners/residents mail in or contact the call line to provide their
information and consent to sampling, they will be scheduled for sampling.
Based on the analytical results from the sampling described above, additional private wells
will be sampled within a quarter mile radius of Attachment C PFAS concentrations exceeding
CO criteria.
Furthermore, in the revised Interim Plan, no restrictions are placed on the total number of
private wells to be sampled in each county.
3. The revised Interim Plan must provide that sampling include not only residences, but other
property types where a private well is used as the primary source of drinking water,
including schools and day cares, churches, mobile home parks, healthcare facilities,
commercial properties, etc.
As Chemours previously advised DEQ, the initial Interim Plan was not limited to only
residences. Nonetheless, the Interim Plan has been revised to specify sampling eligibility for
properties where the private well is used as the primary source of drinking water, including
households, businesses, schools or public buildings in accordance with Paragraphs 19 and 20
of the CO.
4. Chemours must directly contact the private well owners who meet the eligibility criteria in
Section 2.1.3 as modified to offer testing.
As discussed in response to comment #2, Chemours proposes to contact by mail those whose
addresses are within the areas of the modified sampling criteria (see response to comment #1
and Section 2.1.1 of revised Interim Plan). These letters will request well owners/residents to
provide a response on whether they are connected to public water (if the status of public
water connection is unknown) and if their primary source of drinking water is a private well
and will offer sampling of their private well.
5. Residents who contact Chemours to request testing must all be logged in Chemours’
database of sampling requests, even if they do not qualify for testing in this first round of
sampling.
All residents, regardless of eligibility, are currently being logged in Chemours’ database and
will continue to be logged throughout the duration of the sampling program.
6. Chemours must provide bottled water within 3 days of receipt of testing results to impacted
locations with detections of Table 3+ compounds at or above 10 parts per trillion (ppt) for
an individual compound or 70 ppt combined. In addition, Chemours must provide
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replacement drinking water supplies as required in paragraphs 19 and 20 of the Consent
Order.

The Interim Plan has been revised to specify provision of bottled water to qualifying
locations within 3 days of receipt of testing results.
In accordance with the criteria specified in the CO, bottled water will be offered for locations
with detections of any single Attachment C PFAS compound is greater than or equal to 10
nanograms per liter (ng/L), the sum of the Attachment C PFAS compounds is greater than or
equal to 70 ng/L, or hexafluoropropylene oxide dimer acid (HFPO-DA) is greater than or
equal to 140 ng/L.
Qualified residents will be offered permanent replacement drinking water within the
timeframe set forth in the CO. This offer may include connection to public water were
Chemours determines that is appropriate. For addresses where Chemours does not offer, or
the resident does not accept, connections to public water, Chemours will offer water filtration
systems consistent with CO paragraph 20. Chemours may propose updates to this process in
the Updated Plan.
7. The revised Interim Plan must describe a proposed step out or other systematic approach to
drinking water sampling based on the results of data collected under Steps 1A and 1B as
modified. For example, if sampling near the river finds contamination, Chemours should
describe an approach for conducting sampling to determine the extent of the contamination.
Chemours agrees with the need for a data-driven sampling design and has prepared the
Interim Plan (dated February 1, 2022) to achieve this purpose. Where data are available,
requests from DEQ have been incorporated into the revised Interim Plan. As stated in
response to comments # 2 and #4, Chemours will expand the current sampling effort to
include an extensive community outreach across the four counties. As part of the community
outreach, eligible addresses will be contacted by mail to request information related to public
water connection and primary drinking water source and to offer sampling.

As part of the Interim Plan and the assessment framework, preliminary information will be
collected which will form the basis of a detailed sampling program. This detailed sampling
design will be provided in the Updated Four Counties Sampling and Drinking Water Plan
(Step 3 of the proposed workflow) which will include steps to complete delineation of
Attachment C PFAS contamination, if necessary, and to provide framework by which
permanent replacement drinking water supplies may be provided.

Based on the data collected during implementation of this Interim Four Counties Sampling
and Drinking Water Plan, updates may be needed. A review and reporting of the sampling
program will be completed on a quarterly basis, and adjustments will be made, as required.
Modifications and/or updates to the Interim Plan will be summarized in the quarterly reports
and transmitted to DEQ.
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8. [Comment from March 28, 2022 letter] 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).
As stated in response to comment #2, the eligibility criteria have been modified to include
wells near tributaries to the Cape Fear, floodplains, and direct injection of Cape Fear River
water. Information on areas where PFAS may have seeped into surrounding aquifers, such as
areas of leaking utility pipes, is limited. Information obtained to date show that these areas are
within the public water distribution areas and captured by the current sampling eligibility
criteria.
We believe that the revised Interim Plan fully addresses DEQ’s comments and concerns and is
an appropriate approach for addressing private wells in the four counties in light of the limited
information and data available. We are prepared to address any remaining questions or concerns
directly with DEQ. If you have any questions or would like to discuss this matter further, please
contact me at 910-678-1415.

Sincerely,

Dawn M. Hughes
Plant Manager
Chemours – Fayetteville Works