Why Certification Beyond PFOA and PFOS Matters Now
For most of the history of PFAS regulation in drinking water, certification for PFOA and PFOS removal was sufficient to demonstrate product compliance with applicable standards. The two compounds had health advisories; they were the regulatory focus; and testing protocols were designed around them. Filter manufacturers could obtain NSF/ANSI 53 certification for PFOA/PFOS and reasonably represent their products as certified for PFAS removal without anyone questioning whether that claim extended to the full compound spectrum.
The EPA’s 2024 final MCL rule changed this calculus fundamentally. By establishing binding Maximum Contaminant Levels for PFHxS and PFNA — in addition to PFOA and PFOS — and by including these in a hazard index calculation that makes their combined presence actionable even at lower individual concentrations, the rule created a direct regulatory pathway through which short-chain PFAS certification matters. Buyers who specify products must now consider whether the certification they are relying on actually covers the compounds they need to address.
What Multi-Compound Testing Involves at KCL
KCL — Korea Conformity Laboratories — is an accredited testing laboratory that conducts multi-compound PFAS performance evaluations for filter media under NSF/ANSI 53-equivalent protocols. Multi-compound testing differs from standard PFOA/PFOS testing in several important ways: it requires challenge water preparations for multiple PFAS species simultaneously; it requires analytical methods capable of resolving compounds across the full targeted range; and it must be designed to detect performance differences between compounds that have different adsorption kinetics and binding affinities.
For short-chain PFAS like PFNA (C9 perfluoroalkyl carboxylic acid) and PFHxS (C6 perfluoroalkyl sulfonic acid), the testing conditions must be designed to detect removal at the low-concentration levels relevant to the MCL framework. This requires high-sensitivity analytical methods with detection limits well below the MCL thresholds, and challenge concentrations that bracket the expected operating range rather than using artificially high spiking levels that obscure performance at relevant concentrations.
The analytical complexity of multi-compound PFAS testing is non-trivial. Compounds at similar chain lengths and with similar structures can co-elute in some analytical methods, requiring careful method validation to distinguish compounds reliably. Accredited laboratories conducting this work invest significantly in method development and quality control to ensure that compound-specific results are accurate.
Bluelabs’ Decision to Pursue PFNA and PFHxS Verification
Bluelabs made the decision to pursue compound-specific certification for PFHxS and PFNA through KCL’s multi-compound testing protocol in direct response to the direction of the regulatory framework. The rationale was straightforward: if MARISORB™ claims to provide broad-spectrum PFAS removal across C3 through C14 chain lengths, that claim should be verified for the compounds that the regulatory framework has identified as the most challenging and consequential — not just the legacy long-chain compounds for which conventional GAC already performs adequately.
PFHxS and PFNA were prioritized because they represent two important dimensions of the MCL compound set: PFHxS is a sulfonate compound at C6 chain length — a short-chain compound for which conventional GAC shows limited removal; PFNA is a carboxylate at C9 — a medium-chain compound in the MCL framework that is often used as a test case for products targeting the newer regulatory compounds. Verification for both provides a more meaningful demonstration of broad-spectrum capability than PFOA/PFOS verification alone.
What the Results Show and Why They Matter for Buyers
The KCL multi-compound testing results for MARISORB™ confirmed removal performance for both PFHxS and PFNA under the testing protocol, supporting the compound-specific certification claims. These results are significant for buyers for two reasons. First, they demonstrate that the material’s electrostatic and fluorophilic binding mechanisms are effective for compounds that represent different points on the chain-length spectrum. Second, they provide a verified basis for performance claims that is substantially more defensible than manufacturer self-testing.
For buyers writing procurement specifications that require certification beyond PFOA/PFOS, or for those evaluating filter media for compliance with the full EPA MCL compound set, compound-specific certification through an accredited laboratory is the appropriate standard of evidence. MARISORB™’s KCL-verified certification for PFHxS and PFNA removal represents the type of documentation that the current regulatory and procurement environment is increasingly demanding.