At a glance
| Chemical family | Short-chain perfluoroalkyl carboxylic acid (a "C5 PFCA") — a C4F9 perfluorinated tail plus a carboxylic-acid head, with anionic-surfactant behaviour. Sits between PFBA (C4) and PFHxA (C6), well below PFOA (C8). Formula C5HF9O2; PubChem CID 75921; IUPAC 2,2,3,3,4,4,5,5,5-nonafluoropentanoic acid (synonyms: nonafluoropentanoic acid, perfluorovaleric acid) |
| CAS number | 2706-90-3 |
| Classification | NOT individually regulated in US drinking water; NOT on California Proposition 65; NOT an individual REACH Substance of Very High Concern; NOT listed under the Stockholm Convention; NOT classified by IARC. Captured only by emerging class-wide actions — Canada's PFAS class listing under CEPA and the proposed EU universal PFAS restriction. Included as one of 29 PFAS monitored under US EPA UCMR 5 and captured by TSCA Section 8(a)(7) class-wide PFAS reporting |
| Where you encounter it | Drinking water and house dust as a terminal degradation product of fluorotelomer-based stain- and water-repellent finishes on textiles, carpets and upholstery; direct short-chain surfactant use in coatings and packaging. Highly water-mobile, so drinking water is the dominant population-level pathway |
| Sleep micro environment relevance | Indirect. PFPeA is not a mattress off-gassing VOC. It appears in the bedroom as a low-level component of house dust in homes with PFAS-treated soft furnishings, and it contributes to total PFAS body burden through drinking water. Relevant to bedroom chemistry mainly as a breakdown product of treated furnishings rather than a direct emission |
| Activated carbon capture | Poor. Short-chain PFAS such as PFPeA break through granular activated carbon (GAC) faster than long-chain PFAS; anion-exchange resins and reverse osmosis perform better, but short-chain removal remains harder than long-chain across the board. Peer-reviewed — Gagliano et al. 2019 |
Regulatory & certification status
Where PFPeA (Perfluoropentanoic Acid) stands across the major regulatory systems and the certifications a bedroom product might carry. Each row links to the governing instrument; where a jurisdiction has no specific measure, that is stated plainly rather than left blank. The recurring theme: PFPeA is a short C5 acid, so it falls outside almost every individual PFAS rule, which are written around the long-chain compounds.
| United States | PFPeA is NOT in EPA's Final PFAS National Primary Drinking Water Regulation (26 April 2024), which set enforceable limits only for PFOA and PFOS (4 ng/L) and PFHxS, PFNA and HFPO-DA (10 ng/L), plus a Hazard Index of 1 for the PFHxS/PFNA/HFPO-DA/PFBS mixture — PFPeA is in none of these. It IS one of the 29 PFAS monitored under EPA's fifth Unregulated Contaminant Monitoring Rule (UCMR 5), and it is captured by class-wide PFAS reporting under TSCA Section 8(a)(7) (final rule 11 October 2023). A May 2025 EPA proposal would keep the PFOA/PFOS limits but rescind the PFHxS/PFNA/HFPO-DA/PFBS limits and extend compliance timelines; PFPeA is unaffected either way. Regulatory — Federal Register · EPA UCMR 5 · 2025 rescission proposal |
| United States — California Prop 65 | PFPeA (CAS 2706-90-3) is not listed under California Proposition 65. The listed perfluoro compounds are PFOA, PFOS and PFNA; PFPeA is not among them. Regulatory — OEHHA |
| European Union | PFPeA is not an individual REACH Substance of Very High Concern and has no PFPeA-specific Annex XVII restriction. It would, however, be captured by the proposed universal PFAS restriction submitted in January 2023 by Germany, Denmark, the Netherlands, Norway and Sweden, which remains a draft under evaluation. Regulatory — ECHA PFAS hot topic |
| Canada | PFPeA is not named individually, but it falls within the scope of Canada's 2025 State of PFAS conclusion that the class of PFAS (excluding fluoropolymers) meets the toxicity criteria under CEPA, with a phased prohibition proposed. This is a class-level risk-management measure rather than a PFPeA-specific rule. Regulatory — Government of Canada |
| Australia | The NHMRC's updated Australian Drinking Water Guidelines (2025) set guideline values for PFOS, PFOA, PFHxS and PFBS only — there is no PFPeA value. Regulatory — NHMRC |
| United Kingdom | No PFPeA-specific UK measure is identified. PFPeA is not on the UK REACH Candidate List (maintained separately by HSE), and HSE's PFAS regulatory management option analysis (RMOA) work is class-level and ongoing. Treat as an honest absence rather than an active control. Regulatory — HSE |
| International | PFPeA is not listed under the Stockholm Convention on POPs, whose listed PFAS are PFOS, PFOA, PFHxS and the long-chain C9–C21 PFCAs — a short-chain C5 acid such as PFPeA sits outside all of these. PFPeA has not been evaluated by IARC. Regulatory — Stockholm Convention |
| Certifications | CertiPUR-US does NOT address PFAS — its foam criteria cover ozone depleters, specified flame retardants, heavy metals, formaldehyde, prohibited phthalates and CMR substances, but PFAS are not named or tested. OEKO-TEX Standard 100 regulates PFAS in certified textiles through a total-fluorine limit and a defined PFAS test, an approach that would capture PFPeA even though it is not individually named. GREENGUARD / GREENGUARD Gold is a low-VOC emissions certification and does not screen for a non-volatile PFAS like this. Industry — CertiPUR-US · OEKO-TEX |
| The 72-hour test window | Largely missed. PFPeA is a non-volatile, surface-active perfluorinated acid that partitions to dust, water and surfaces rather than off-gassing, so a short ~72-hour VOC chamber emissions test does not reliably capture it; it is instead measured by targeted PFAS analysis (LC-MS/MS) of materials, dust or biofluids. Inferred — from the compound's volatility/emission profile versus the VOC focus of short chamber tests |
What it is
PFPeA — perfluoropentanoic acid, CAS 2706-90-3 — is the 5-carbon perfluoroalkyl carboxylic acid. Structurally it is a C4F9 perfluorinated tail attached to a carboxylic-acid head group (formula C5HF9O2; PubChem CID 75921), whose systematic name is 2,2,3,3,4,4,5,5,5-nonafluoropentanoic acid and which is also called nonafluoropentanoic acid or perfluorovaleric acid. It sits one carbon above PFBA (C4), one below PFHxA (C6), and three below the long-chain PFOA (C8). Because of that short tail it is classed as a "short-chain" PFAS.
Chain length drives behaviour across the perfluoroalkyl carboxylate spectrum. Shorter chains are more water-soluble, adsorb less strongly to carbon, and — on the current evidence — accumulate less in the body than the long-chain compounds; longer chains are more lipophilic and more bioaccumulative. PFPeA's short chain is exactly why it behaves the way it does in the environment: it is extremely mobile in water while remaining, like every PFAS, extremely persistent thanks to its carbon–fluorine backbone. The result is a compound that distributes quickly and broadly to drinking water and dust, and then does not break down.
Where you encounter it
The "regrettable substitution" story
After the long-chain PFOA and PFOS phase-out, manufacturers shifted toward short-chain and fluorotelomer chemistries that were marketed as less bioaccumulative. Critics of that shift call it "regrettable substitution": the short-chain replacements are just as persistent, and their higher mobility means they spread further and are harder to remove from water. PFPeA is a textbook example of the pattern — it is one of the compounds that showed up in the water once the long-chain compounds were curtailed.
As a breakdown product of treated furnishings
PFPeA reaches the home in two ways. It is used directly, to a limited extent, as a short-chain surfactant or surface-protector in textile treatments, coatings and packaging. More importantly, it is a terminal "dead-end" degradation product of fluorotelomer-based stain- and water-repellent finishes on carpets, upholstery and technical fabrics. As those finishes weather and degrade, they yield short perfluoroalkyl acids including PFPeA. Its short tail makes it extremely water-soluble, so it partitions readily to water and appears in indoor dust wherever treated soft furnishings are present.
In drinking water — the dominant pathway
Because it is so mobile, drinking water is the dominant population-level PFPeA exposure route. According to EPA's UCMR 5 occurrence data (2023–2025), PFPeA was the most-detected PFAS and the second most-detected substance overall in the monitoring program — present in 19.75% of 10,289 public water systems sampled. Regulatory Where it was detected, the median concentration was about 5.5 ng/L (0.0055 µg/L) and the maximum reported was 358 ng/L (0.358 µg/L). That combination — nearly one system in five, but almost always at single-digit nanogram concentrations — is the defining shape of the PFPeA data: ubiquity, not intensity.
What the research says
Short-chain PFAS: mobile, persistent, hard to treat
Brendel and colleagues (2018) in Environmental Sciences Europe, working from the German Environment Agency, set out the environmental case against short-chain perfluoroalkyl acids as a group. Peer-reviewed They describe short-chain PFAS as highly mobile in soil and water, extremely persistent as end products, quick to distribute to — and contaminate — drinking-water resources, and poorly addressed by conventional water treatment, producing what they call "everlasting background concentrations." Their argument is that these compounds are of a concern equivalent to classic persistent, bioaccumulative and toxic (PBT) substances and should therefore be treated as Substances of Very High Concern under REACH. PFPeA is squarely within the short-chain group this paper analyses.
Why carbon filters struggle
Gagliano and colleagues (2019) in Water Research reviewed the removal of PFAS from water by adsorption. Peer-reviewed Their central finding for a short-chain compound like PFPeA: adsorption capacity is lower for short-chain than for long-chain PFAS, so short-chain removal is more challenging, with rapid breakthrough on granular activated carbon (GAC). Strong anion-exchange resins removed both short- and long-chain PFAS better than GAC. In practical terms, a carbon-only filter is the wrong tool for PFPeA; reverse osmosis or a certified anion-exchange system is the right one.
Toxicology — thinner than for the long-chain compounds
The single-compound toxicology of short-chain PFCAs is much thinner than for PFOA or PFOS, and PFPeA specifically has not been a major research target. Some vendor and product data point to indicative effects — such as PPARα activation, or liver-weight and skin changes in mice after topical application — but these are industry or preliminary observations rather than established human findings, and should be read as indicative, not established. Industry — indicative, not established The honest position is that the long-term human health effects of PFPeA specifically remain poorly characterized. Inferred from the sparse single-compound literature relative to PFOA/PFOS
What helps reduce exposure
Favour reverse osmosis or anion-exchange over carbon-only filtration. If reducing PFAS — and short-chain PFAS in particular — is your goal, an NSF/ANSI 58 reverse-osmosis system or a certified anion-exchange system will outperform a plain granular-carbon filter, which short-chain compounds break through quickly.
Reduce sources: think twice about stain-repellent treatments. PFPeA in the home traces largely to fluorotelomer stain- and water-repellent finishes on carpets, upholstery and technical fabrics. Choosing untreated soft furnishings, or skipping optional "stain-guard" add-ons, removes a source at the front end.
HEPA-vacuum carpets and upholstery regularly. Indoor dust is the bedroom-relevant PFPeA reservoir in homes with treated textiles. Standard PFAS dust mitigation — HEPA vacuuming and damp-dusting — lowers the contribution.
Check your utility's UCMR 5 results. Because PFPeA was the most-detected PFAS in UCMR 5, many systems will show it. A detectable result is common and usually low; use it as a prompt to look at your overall PFAS picture rather than as a single-compound alarm.
What does NOT help
- Assuming the federal PFAS rule covers it. The 2024 NPDWR limits apply to PFOA, PFOS, PFHxS, PFNA and HFPO-DA. PFPeA is not among them and has no federal limit.
- Plain carbon pitcher filters. Short-chain PFAS break through granular activated carbon quickly; without reverse osmosis or certified anion-exchange, PFPeA reduction is unreliable.
- "PFOA-free" labels. They say nothing about short-chain replacements like PFPeA, which is precisely the kind of compound that filled the gap after the long-chain phase-out.
- Boiling water. Concentrates rather than removes PFAS.
Open research questions
- PFPeA-specific dose–response in humans — most health studies aggregate PFPeA into PFAS-mixture analyses, so standalone conclusions are limited. Speculation re: timeline for standalone characterization
- Whether the large UCMR 5 detection-versus-regulation gap prompts future federal or state action on short-chain PFAS as a group. Inferred from EPA's class-wide monitoring and reporting posture
- Real-world short-chain removal performance of consumer point-of-use systems for PFPeA specifically, beyond bench adsorption studies. Inferred from the chain-length adsorption patterns in Gagliano et al. 2019
Where you meet Pfpea across your home
The same compound turns up in more than one place you live. Here's where it shows up in Embr — each links to the full breakdown for that part of your home.
Citations
- US Environmental Protection Agency (2024). PFAS National Primary Drinking Water Regulation — Final Rule. Federal Register, 26 April 2024. Note: PFPeA is NOT in any individual MCL or the Hazard Index. federalregister.gov Regulatory
- US Environmental Protection Agency. Fifth Unregulated Contaminant Monitoring Rule (UCMR 5). Occurrence data 2023–2025; PFPeA was the most-detected PFAS (19.75% of 10,289 systems; median 5.5 ng/L; max 358 ng/L). epa.gov/dwucmr Regulatory — occurrence-data source
- California Office of Environmental Health Hazard Assessment (OEHHA). Proposition 65 List — PFPeA (CAS 2706-90-3) not listed. oehha.ca.gov Regulatory
- Brendel S, Fetter É, Staude C, Vierke L, Biegel-Engler A (2018). Short-chain perfluoroalkyl acids: environmental concerns and a regulatory strategy under REACH. Environmental Sciences Europe, 30(1):9. DOI 10.1186/s12302-018-0134-4 Peer-reviewed — short-chain PFAS mobility, persistence and treatment
- Gagliano E, Sgroi M, Falciglia PP, Vagliasindi FGA, Roccaro P (2019). Removal of poly- and perfluoroalkyl substances (PFAS) from water by adsorption: Role of PFAS chain length, effect of organic matter and challenges in adsorbent regeneration. Water Research, 171:115381. DOI 10.1016/j.watres.2019.115381 Peer-reviewed — short-chain adsorption and GAC breakthrough
- European Chemicals Agency (ECHA). Per- and polyfluoroalkyl substances (PFAS) — hot topic and proposed universal PFAS restriction (submitted January 2023 by DE/DK/NL/NO/SE). echa.europa.eu Regulatory
- Environment and Climate Change Canada / Health Canada. Risk management approach for per- and polyfluoroalkyl substances (PFAS) — 2025 State of PFAS class conclusion under CEPA. canada.ca Regulatory — class-level listing
- National Health and Medical Research Council (NHMRC). Australian Drinking Water Guidelines — PFAS review (2025); guideline values set for PFOS, PFOA, PFHxS and PFBS only. nhmrc.gov.au Regulatory
- Stockholm Convention on Persistent Organic Pollutants. PFAS overview — listed PFAS are PFOS, PFOA, PFHxS and long-chain C9–C21 PFCAs; short-chain C5 PFPeA is outside these. pops.int Regulatory
Frequently asked questions
What is PFPeA?
PFPeA — perfluoropentanoic acid, CAS 2706-90-3 — is a 5-carbon perfluoroalkyl carboxylic acid (a C5 PFCA), built from a C4F9 perfluorinated tail and a carboxylic-acid head group. It sits between PFBA (C4) and PFHxA (C6) and well below the long-chain PFOA (C8), which makes it a "short-chain" PFAS. PFPeA is rarely a headline industrial chemical in its own right; it appears in the environment mostly as a highly water-mobile terminal degradation product of fluorotelomer-based stain- and water-repellent finishes, and it was the single most-detected PFAS in EPA's fifth Unregulated Contaminant Monitoring Rule (UCMR 5).
Is PFPeA regulated in drinking water?
No — PFPeA carries no federal US drinking-water limit. It is not in EPA's April 2024 Final PFAS National Primary Drinking Water Regulation, which set individual limits only for PFOA and PFOS (4 ng/L) and PFHxS, PFNA and HFPO-DA (10 ng/L), plus a Hazard Index for a four-PFAS mixture. PFPeA is in none of those. It IS one of the 29 PFAS monitored under UCMR 5 (2023-2025), and it is captured by class-wide PFAS reporting under TSCA Section 8(a)(7). Australia's 2025 drinking-water guidelines and the EU's individual REACH controls likewise do not name PFPeA; it is regulated, if at all, only by emerging class actions in Canada and the proposed EU universal PFAS restriction.
How common is PFPeA in US drinking water?
Very common at low concentrations. According to EPA UCMR 5 occurrence data (2023-2025), PFPeA was the most-detected PFAS and the second most-detected substance overall in the program — found in 19.75% of 10,289 public water systems sampled. Where it was detected, the median concentration was about 5.5 ng/L (0.0055 µg/L) and the maximum reported was 358 ng/L (0.358 µg/L). So the PFPeA story is one of ubiquity plus a regulatory gap, not of high individual concentrations.
Where does PFPeA come from?
After the long-chain PFOA/PFOS phase-out, industry shifted toward short-chain and fluorotelomer chemistries marketed as less bioaccumulative — the "regrettable substitution" critique. PFPeA reaches the home two ways: as a direct short-chain surfactant or surface-protector in textile treatments, coatings and packaging; and, more importantly, as a terminal "dead-end" degradation product of fluorotelomer stain- and water-repellent finishes on carpets, upholstery and technical fabrics. Its short tail makes it extremely water-soluble and mobile, while its carbon–fluorine backbone makes it extremely persistent — so it distributes quickly to drinking water and is measurable in indoor dust.
Do carbon water filters remove PFPeA?
Poorly. Short-chain PFAS like PFPeA break through granular activated carbon (GAC) filters faster than long-chain PFAS such as PFOA, because they adsorb less strongly. Peer-reviewed adsorption studies find short-chain removal is consistently more challenging than long-chain removal on carbon, while strong anion-exchange resins and reverse osmosis perform better. If reducing short-chain PFAS is your goal, favour reverse osmosis or a certified anion-exchange system over a carbon-only filter.
Is PFPeA a mattress off-gassing chemical?
No. PFPeA is a non-volatile, surface-active perfluorinated acid, not a VOC that off-gasses from foam. It partitions to water, dust and surfaces and is measured by targeted PFAS analysis (LC-MS/MS), not by the short VOC chamber tests used for formaldehyde or solvent emissions. In the bedroom it is relevant mainly as a low-level component of house dust in homes with PFAS-treated soft furnishings, and as part of total PFAS body burden — not as something the mattress itself emits.
Should I worry about PFPeA?
Watchful, not alarmed. PFPeA is one of the most frequently detected PFAS in US water, but almost always at low nanogram-per-litre concentrations (median around 5.5 ng/L). The notable facts are structural rather than acute: it is extremely mobile and persistent, it slips through common carbon filters, and it sits outside every individual drinking-water limit in the US, EU and Australia. The reasonable response is to reduce sources (treated stain-repellent textiles), favour reverse osmosis or anion-exchange over carbon-only filtration if PFAS reduction is the goal, and treat the large detection-versus-regulation gap as the real signal to watch.
Related compounds
Embr is a sleep environment company researching the chemistry of the bedroom. See the methodology page for how this Atlas tags claims by evidence strength. For broader context on PFAS exposure pathways and firefighter take-home contamination, see non-toxic bedroom and farm family sleep.
Last reviewed 2026-07-13. If you find a factual error, contact us.