The ownership structure for ships used in international shipping is anything but straightforward. For instance, for the the MV Dali (the ship that crashed into the Francis Scott Key Bridge) you might think we can go after Maersk, but in reality they're only chartering it. It was actually built by Hyundai Heavy Industries in South Korea for a Greek company but later sold to a Singaporean company, operated by a different Singaporean company, and crewed by 20 Indians and 1 Sri Lankan. In this complex web of ownership/relationships how do you exactly "enforce regulation from the ship building side "?

Well as I (naively) suggested whoever owns the actual ship (and thus disposes of it) can claim on an escrow that isn't released until the ship has been verifiable disposed of in an environmentally sound fashion. So if the ship ever is sold to another party, that would be built into the purchase cost (that they could claim this money), even to the final purchaser (the wreckers). Probably some huge loophole or perverse incentive that I haven't thought of, but that's at least one suggestion.