Fwiw, these situations, where there is not a responsible polluter with enough money to go ahead with a reasonable cleanup, are supposed to be covered out of a trust fund, which is funded by a general tax on likely-to-pollute industries. Except: this tax was repealed in 1995, and the trust fund is now out of money. So they don't get cleaned up.

There are occasional proposals to reinstate the Superfund tax, but the GOP has been blocking them.