Yeah it’s potentially a much higher cost, depending on how class-action lawsuits play out, but that study doesn’t necessarily say it’s coating the surface of the ocean. It’s diluted into the ocean itself, and because it likes to stick to foam it tends to accumulate at higher concentrations close to the surface. That study is documenting that air particles have a much higher concentration than what’s typically seen diluted in sea water, so it’s essentially congregating in the air-water interface zone.

But yes, your point is well taken that they’re facing catastrophic liability costs from a combination of past health impacts and future cleanup/removal.