PFAS foam doesn't stop at the shoreline.
The world fleet runs on firefighting foam. As of January 1, 2026 the International Maritime Organization (IMO) bans firefighting foam containing perfluorooctane sulfonic acid (PFOS) aboard ships, but roughly 40,000 vessels still carry foam made with per- and polyfluoroalkyl substances (PFAS), compliance phases in ship by ship, and most ports lack the infrastructure to destroy what comes off, or to resupply a fluorine-free replacement. The same custody gap as on land, at every dock in the world.
Why the maritime transition is stuck
The PFOS only loophole
The IMO ban targets PFOS specifically. Modern C6 and 6:2 fluorotelomer foams are still PFAS and remain legal at sea. The IMO has signaled it may widen the prohibition to the full PFAS family in coming years.
Source ↗Rolling per ship deadlines
Existing ships comply only at their first safety equipment survey on or after Jan 1, 2026, so the world fleet phases in across 2026 and 2027, not on one fixed cutoff. There is no single fleet wide date.
Source ↗No disposal infrastructure
Foam removed from ships has nowhere standardized to go, ports lack adequate facilities and the destruction process needs regulatory auditing. The same gap PFAS Reference tracks on land exists, unsolved, at every port.
Source ↗The rebound problem
Untreated suppression piping leaches PFAS back into clean fluorine-free foam, one study found 1.6 g/L PFAS in F3 a year after incomplete decontamination. Swapping the foam isn't enough; the system stays contaminated.
Source ↗Foam comes off the ship, then what?
A vessel pulling into port has to land its PFAS foam and take on a compliant replacement before it sails. Today that means two unsolved problems at once: nowhere standardized to destroy the old foam, and no reliable dockside resupply. Destruction and replenishment are the same service, at the same place, the same visit. Whoever closes that loop at the dock owns the maritime transition.
How ships are meant to be kept from dumping it.
The rule is not only to stop using PFOS foam. When foam is taken off a ship it must be delivered to a shore based reception facility, never discharged. Three layers back that up. The International Convention for the Prevention of Pollution from Ships (MARPOL) prohibits discharging operational waste to the sea. The flag state, the country whose flag a ship flies, writes these rules into its own law, issues the ship's certificates, and surveys the vessel. And Port State Control lets a port or coastal country inspect and detain a foreign ship in its waters, whatever flag it flies, when it is not compliant. A spill or release must also be reported. The full legal detail is on the laws of the sea page.