Toggle Search Menu

We are committed to taking a leadership role in environmental stewardship.

C3 Dimer Acid and PFAS

C3 Dimer Acid is used in the manufacture of many products by Chemours. This material, also known and referred to as HFPO-dimer acid, HFPO-DA or Gen-X, has been detected at low levels in the environment near our manufacturing facility at Fayetteville.

Dr. Damian Shea, Professor of Environmental Chemistry and Toxicology at North Carolina State University, recently completed a detailed toxicology analysis of the currently available data regarding C3 Dimer Acid. Dr. Shea said, “Over a decade of scientific data has been collected regarding the safety profile of C3 dimer acid. These data, including numerous toxicology studies, provide compelling scientific evidence that the low levels of C3 dimer acid detected in the environment do not pose a risk to human health.”

As part of our efforts with respect to C3 Dimer Acid as well as other per- and polyfluoroalkyl substances (PFAS), Chemours has worked to develop more sensitive analytical methods to detect and quantify individual PFAS waste product compounds. These waste products exist at extremely low levels, and up until very recently, methods did not exist to enable us to do further assessment for many of these compounds. Chemours is working with external laboratories to conduct toxicity testing for these compounds.

In addition, as part of our Clean Water Act permit at Fayetteville, we regularly test for the presence of toxic compounds in our discharge water. This test (called a bioassay) exposes a highly sensitive living organism (Daphnia) to the water discharged from our plant, including any PFAS waste products. We conduct these bioassays on a quarterly basis and have been doing this for over 22 years. Except for one sample in 2012, which was subsequently re-tested and resulted in no toxic or harmful effect, we have never seen any toxic or harmful effect.

Finally, in addition to our regular testing program, in October of 2017, we conducted another study—the Fathead Minnow Chronic Toxicity Study, EPA test method 1001.0. This study was used to assess the effects of our water discharge, including any PFAS waste products, on the physiological, biochemical and embryonic (fetal) effects on this sensitive organism. We saw no toxic or harmful effect from this study.

Nonetheless, we take the concerns of our Fayetteville neighbors seriously and have taken swift action to address the community’s concerns, working closely with state and federal regulators.

Since the summer of 2017, Chemours has taken numerous steps to dramatically reduce water discharges and air emissions of C3 Dimer Acid and other PFAS compounds from Fayetteville Works. We are also developing and implementing comprehensive remediation plans to address groundwater concerns. Chemours entered a Consent Order agreement with the North Carolina Department of Environmental Quality (NCDEQ) and Cape Fear River Watch, which was approved by the Superior Court for Bladen County on February 25, 2019. Working under the oversight of the NCDEQ and pursuant to the comprehensive Consent Order, we are taking a wide array of substantial actions to ensure that current and future operations are protective of people and the environment. Great progress has already been made, and Chemours is addressing emissions in an industry-leading manner for environmental protection. These actions are documented in our Consent Order Compliance submissions.

Investing in Long-Term Solutions

Leveraging the knowledge of highly-skilled scientists, engineers and other experts, Chemours has designed specialized, long-term, state-of-the-art emission control solutions. The solutions Chemours is implementing are intended to meet the expectations of the community for the long term. We are committed to eliminating 99% of all emissions of C3 Dimer Acid and other PFAS compounds per Consent Order requirements, and are currently investing well over 100 million dollars to enable us to achieve this commitment.

Air Emissions Control

In consultation with the NCDEQ and Cape Fear River Watch, Chemours is taking the following actions to address air emissions:

  1. Installed three carbon adsorption air emissions control systems as well as a secondary scrubber to further capture C3 Dimer Acid and other PFAS emissions; these systems are expected to contribute to a 92% facility-wide reduction in C3 Dimer Acid air emissions for 2019 from 2017 levels.
  2. Working to install a custom-designed emission control facility that includes a custom-built, state-of-the-art thermal oxidizer, which will contribute to the elimination of 99% of all facility-wide air emissions of C3 Dimer Acid and other PFAS compounds by the end of 2019.

Water Management

On-Site Wastewater

In June 2017, Chemours voluntarily limited wastewater discharges containing C3 Dimer Acid, capturing 99.9% in just two months. By November 2017, Chemours eliminated all process wastewater (excluding non-contact cooling water) from its operations from discharging into the Cape Fear River.

Cape Fear River Water Sampling

Chemours periodically conducts sampling of the water in the Cape Fear River at various locations. The following information contains final data from the river water sampling program.

Cape Fear River Water Sampling Results from Mile "0" to Mile 132, Report Completed September 2018

Off-Site Well Sampling and Drinking Water

Chemours has moved quickly to determine off-site residential well impacts through an extensive sampling program. Specifically, the following actions have been taken since September 2017:

1. Implemented an ongoing well sampling program covering a radius of approximately five miles; extended sampling per Consent Order requirements; approximately 1,000 homes sampled to date.

Owners and residents of properties have received or will receive a letter from Chemours explaining the well sampling program, requesting permission to sample their well, and providing instructions on how to schedule time with our sampling team.

For residents whose well has levels of C3 Dimer Acid or certain PFAS compounds greater than 10 ppt, bottled drinking water is available free of charge, pursuant to Consent Order requirements. A letter with instructions on how to receive bottled drinking water along with an initial bottled water delivery is provided for qualified residences.

2. Completed six pilot studies on Granular Activated Carbon (GAC) requested by NCDEQ:

*Location 48 was removed from the sampling program at the request of the resident. Results shown are from April 12th, 2018 thru October 25th, 2018.

**Location 71-resident was unable to allow access for Jan. 29, 2019 sampling.

3. Offered to install and maintain GAC and reverse osmosis (RO) units at all residences eligible under the Consent Order, at no charge to property owners.

Residential drinking water wells testing at or above 140 ppt of HFPO-C3 Dimer Acid (GenX) are eligible for granular activated carbon (GAC) whole-house filtration systems. Households will also receive home delivery of bottled water until systems are installed and effectively removing GenX. If these residences do not want a whole-house GAC filtration system, the homeowner may opt for installation of a reverse osmosis (RO) system on each kitchen and bathroom sink.

Residential drinking water wells testing: (1) greater than 10 ppt of any one PFAS compound, OR (2) at or above 70 ppt for total PFAS are eligible for up to three reverse osmosis (RO) under-the-sink filtration systems. Households will also receive home delivery of bottled water until systems are installed and effectively removing PFAS. Although there is no indication of any harmful health effects of PFAS at these low levels, Chemours has agreed to this program to provide further protection to residents with even very low levels of PFAS in their drinking water.

Residents eligible for either GAC or RO will be informed by Chemours via a letter, either hand delivered with a first delivery of bottled water or sent through the mail.

For information about well testing, granular activated carbon systems, reverse osmosis systems or home delivery of bottled water, call 910-678-1101. A representative will return your call Monday through Friday within 24-48 hours.

Residents may also contact the North Carolina Department of Health and Human Services Division of Public Health at (919) 707-5900 with any health-related questions.

Click here for FAQs about well sampling in the Four Counties Area.

Additional Information

In addition to the extensive data provided to and discussions with global regulators to register the new products, we have regularly presented study results at numerous global scientific conferences and published the results in the peer-reviewed scientific literature. We have also often collaborated with academic researchers in these publications.

  • Gannon, et al., 2016. Absorption, distribution, metabolism and excretion of 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy) proprionic acid, ammonium salt, in rat, mouse, and cynomolgus monkey. Toxicology340:1-9.
    http://dx.doi.org/10.1016/j.tox.2015.12.006
  • Hoke, et al., 2016. Aquatic hazard, bioaccumulation and screening risk assessment for ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate. Chemosphere 149: 336-342.
    http://dx.doi.org/10.1016/j.chemosphere.2016.01.009
  • Buck, 2015. Toxicology Data for Alternative “Short-Chain” Fluorinated Substances in J.C. DeWitt (ed.), Toxicological Effects of Perfluoroalkyl and Polyfluoroalkyl Substances, Molecular and Integrative Toxicology, Chapter 17, pp 451-477.
    http://www.springer.com/us/book/9783319155173
  • Caverly Rae, et al., 2015. Evaluation of chronic toxicity and carcinogenicity of ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate in Sprague-Dawley rats. Toxicology Reports 2: 939-949.
    http://dx.doi.org/10.1016/j.toxrep.2015.06.001

Standardized Analytical Protocol

Chemours has developed a methodology to analyze for a list of compounds referred to as Table 3+ compounds. Chemours has also synthesized the authentic reference materials for Table 3+ compounds and provided those to NCDEQ, EPA and academic researchers to aid in their method development.

Chemours has utilized external, commercial labs (Eurofins Lancaster Laboratories and Test America Sacramento) for analysis of PFAS in water. Those labs employ two methods; one to test for C3 Dimer Acid and other Table 3+ PFAS compounds, and a second which is a modified version of EPA method 537.

North Carolina Department of Environmental Quality

To access information provided by the North Carolina Department of Environmental Quality, click any of the links listed here:

Chemours Response to the United Nations