The Stockholm Convention on Persistent Organic Pollutants, adopted in 2001 and now ratified by over 180 parties, establishes a global framework for eliminating or restricting chemicals that are persistent, bioaccumulative, toxic, and subject to long-range environmental transport. PFAS compounds have increasingly appeared on the Convention’s control lists, reflecting growing scientific consensus about their global environmental and health risks.
PFOS and PFOA on Annex B and Annex A
Perfluorooctane sulfonate (PFOS) and its salts were added to Annex B (Restriction) of the Stockholm Convention in 2009, following a proposal by the European Community. Annex B allows continued use for specific acceptable purposes—most significantly, AFFF (aqueous film-forming foam) in existing firefighting systems and open-pit mining—while prohibiting production and use for all other applications. Countries may register exemptions, but the intent is phase-out over time as alternatives become available.
Perfluorooctanoic acid (PFOA), its salts, and PFOA-related compounds were added to Annex A (Elimination) at the 2019 Conference of Parties, with limited specific exemptions for semiconductor manufacturing and certain medical device applications. Annex A requires parties to prohibit production, use, import, and export except for quantities used in permitted exemptions. This listing was particularly significant given PFOA’s widespread legacy use in cookware coatings, food packaging, and industrial processes.
PFHxS and Emerging Listings
Perfluorohexane sulfonic acid (PFHxS) and its related compounds were added to Annex A at COP10 in 2022, continuing the trend of extending international controls to short-chain and mid-chain PFAS as they were identified as substitutes for PFOS. The listing reflects evidence that PFHxS shares PFOS’s persistence and bioaccumulation characteristics, and has been detected at elevated concentrations in human blood and wildlife globally.
Discussions continue regarding additional PFAS candidates, including PFNA, PFDA, and the broader class of long-chain perfluorocarboxylic acids. Several parties have called for a group-based approach that would address the entire PFAS class rather than proceeding compound-by-compound—a position that has gained support from the scientific advisory body POPRC but faces resistance from countries with significant fluorochemical manufacturing industries.
For global manufacturers and importers, Stockholm Convention listings trigger import/export notification obligations, production phase-outs, and requirements to manage stockpiles as hazardous waste. The Convention’s global reach means that even companies not subject to U.S. or EU PFAS regulations may face compliance obligations based on their country of operation and the specific PFAS compounds involved in their products or processes.