The press release says, “PFAS from Fluorochemical Plant Found in Dust of Nearby Homes.” The headline in the local news report reads, “Toxic Dust? PFAS Found in Homes near NC Plant,” based on a recently published scientific article. As a North Carolina resident, these headlines caught my attention. But once I looked behind the curtain, I found the reality did not match the drama.
Although much attention has been given to PFAS in drinking water, little is known about other sources of exposure, such as air and dust. The few studies that have been done have examined levels in air or dust in homes near contaminated sites, usually military bases.
The Forever Chemicals
Per- and polyfluoroalkyl substances (PFAS) are a large group of chemicals that contain a carbon-fluorine bond, making them resistant to heat, grease, and water. Two PFAS, PFOA, and PFOS, are considered “legacy” as they are no longer manufactured in the US. Due to their persistence, they are still found in the environment, often contaminating the drinking water supply in the communities near military bases where they were used in firefighting foams.
PFAS are also used in consumer products, such as carpets and rugs, stain-resistant cleaning products, building materials, and food packaging. Per- and polyfluoroalkyl ether acid (PFEA) were developed as replacement chemicals and considered less toxic than the “legacy” PFAS. These replacements were examined in the NC study.
The NC Study
The study analyzed 48 PFAS in household dust near the Fayetteville Works fluorochemical plant, the only remaining fluorochemical manufacturing plant in the US, located along the Cape Fear River in Fayetteville, North Carolina. The study found a “diverse suite of PFAS in indoor dust samples from a PFAS-impacted community” and that homes closer to the plant had higher levels of some but not all 48 PFAS.
Nobody wants chemicals in the dust of their homes, and the fact that concentrations were associated with the manufacturing plant could be frightening for local residents.
But a deeper dive suggests a different story:
“Researchers from the GenX Exposure Study have detected PFAS (per- and polyfluoroalkyl substances) associated with a nearby fluorochemical plant in the household dust of homes…”
– Press Release NC State
The wording of the press release suggests that the PFAS reflects current conditions. However, buried in the article is a critical detail: all samples were collected in February 2019 - before the company installed air emissions controls, reportedly removing 99.99% of airborne PFAS. The data are outdated and not helpful in judging today’s exposure risks.
“There were some challenges during sample preparation. Extracts from two samples were accidentally combined and, therefore not analyzed. … Because we only collected one sample from each home, and sometimes struggled to collect sufficient amounts of dust, this limited our ability to recover potential data from samples which were subject to human error.”
This study collected thimble-sized samples of dust from each home's kitchen. Samples so small that when errors occurred in the sampling preparation, they could not be redone. While I applaud the authors’ transparency, this kind of mistake should have prompted additional sampling to ensure reliable results.
“A study found high PFAS levels in household dust near a Chemours plant, raising concerns about another exposure route for residents.” – WRAL News
The usual way to determine if the levels are “high” is to compare them to the regulations set for the chemical, and if they are close to or exceed the regulatory level, they are considered “high.” But there are no regulations for PFAS in dust. So, the only method available is to compare the dust levels with those detected in other studies and see if they are in the same range.
The study found levels for all PFAS ranged from 0.2 to 105.7 nanograms per gram of dust (ng/g). The eight PFAS detected in >90% of the samples had levels ranging from 0.2 to 76.2 ng/g. (For perspective, a nanogram is one billionth of a gram).
- A 2000-2001 study of homes in Ohio and North Carolina reported median levels of 142 ng/g and 201 ng/g for two PFAS.
- A recent study in eight PFAS-affected communities found levels (geometric mean) of 2.2 – 11.8 ng/g, with no correlation to pre-cleanup levels.
- A report from Pennsylvania of 14 homes reported median levels of 1.24 – 72.60 ng/g.
The NC study levels are in the same range as other studies, making the choice of the word “high” more editorial than regulatory.
“Per- and Polyfluoroalkyl Ether Acid (PFEA) Concentrations in Indoor Dust are Higher in Homes Closer to a Fluorochemical Manufacturing Plant”
The article reports on 48 different PFAS compounds and divides them into two subgroups: PFAS and PFEAs. However, this categorization, another choice by the researchers, is another opportunity to introduce bias that fails to differentiate the legacy PFAS that persist despite no longer being manufactured from the “short-chain” PFAS [1], which are generally considered less toxic. Moreover, PFAS concentrations were not higher in homes closer to the plant.
One compound, trifluoroacetic acid (TCA) – a short-chain PFAS with just two carbon atoms was found in 89% of the samples and had the highest median level (105.7 ng/g). Yet the study omits any discussion of TCA’s lower toxicity compared to long-chain PFAS, misleading readers into thinking all detected PFAS are equally toxic.
No one wants industrial chemicals settling in their kitchen dust, but we deserve the full story—not just the scariest version. The study used outdated samples collected before emissions were drastically reduced, analyzed tiny amounts of dust with acknowledged errors, and emphasized the presence of less-toxic PFAS without clarifying their relatively low risk. It also failed to mention that overall PFAS levels weren’t particularly high compared to other communities and that the most prevalent chemical found, TCA, is far less harmful than legacy compounds like PFOA or PFOS. Should we be more concerned about the spin in the press release or the dust on the bookshelf?
[1] Chain refers to the number of carbon atoms in the compound; short-chain PFAS have less than eight.
Source: Per- and Polyfluoroalkyl Ether Acid (PFEA) Concentrations in Indoor Dust are Higher in Homes Closer to a Fluorochemical Manufacturing Facility Environmental Science and Technology DOI: 10.1021/acs.est.4c07043
