There is also additional risk here. If company X made an unknown superfund site, then company Y develops on it. Is company Y then liable if the superfund site becomes known?
A "SuperFund Site" specifically exists because the previous company no longer exists in a form that any assets can be extracted from the legal entity. There's no point in suing something which can't pay damages. It's not just "a business with a toxic piece of land". The term "SuperFund" means the EPA has taken over the responsibility of managing the cleanup after the previous company is gone (eg. The legal entity split off some of their their albatross debts/liabilities such as toxic land that no longer can be used for revenue onto a disposable company that they spun off)
Also land doesn't come with a warranty when it is transferred. So long as the previous owner disclosed all of the relevant information about any hazards known to the seller that is legally required, the old owner is off the hook. If you sell a house with lead paint which was built on landfill that exists near high voltage power lines and the seller described those facts in the escrow period to the buyer (usually in a mass of paperwork), you can't be held liable if the buyer's family develops health issues in that house.
Please don't try to speculate yourself into non-existent legal scenarios.
You didn't have to pay to cleanup a site before using it, because the expectation was that you paid while running your business and the site would be cleaned before you wanted to utilize it.
But now the "Superfund" has been underfunded for like 20 years. Biden's IRA set up a new tax for ten years but, not sure how well that's going.
We literally had the system set up well and working fine, but it cost companies a few dollars so it had to go when the "Greed is good" folks came along.