I think cleaning up old sites should be prioritized; this is kind of the same commons maintenance as decommissioning old nuclear reactors.
Unfortunately the purely-for-profit structure of these long-term ventures can mean that there is no money to cover the cleanup if things go really wrong, depending on who owns the site. I think you need to look at some sort of cleanup fund in escrow as a precondition for building sites like this, which should incentivize improvements in safety measures too.
For sure, I’ve argued for an equivalent of the superfund for NZ previously, and to bring it to bear on site remediations such as this. It’s not a perfect model, but heck it’s better than doing things ad-hoc and asking for point funding, turning things that should have been foreseen and managed over the long term into unpleasant sudden surprises.
Unfortunately the purely-for-profit structure of these long-term ventures can mean that there is no money to cover the cleanup if things go really wrong, depending on who owns the site. I think you need to look at some sort of cleanup fund in escrow as a precondition for building sites like this, which should incentivize improvements in safety measures too.