Sure, it can be cleaned up. Worse projects have been accomplished and turned into high demand development. Here's an excellent article on the Sparow's Point redevelopment in Maryland that shows how it can be done if the demand for the land is high enough and the ownership is flexible enough to think outside the box.
https://www.bloomberg.com/news/features/2019-08-15/amazon-under-armour-and-fedex-set-up-shop-in-an-industrial-graveyard
The site was once the location of the world's biggest steel plant. The old owner went through bankruptcy and a really sharp and nimble management group bought it and figured out how to redevelop it. They'll make hundreds of millions of dollars on it, and they earned every penny of it.
As in the OP's article, the biggest barrier to redevelopment was the unknown environmental risk. The turning point in the project came when the property owners contracted with an environmental engineering company to "buy" the environmental liability from the property owners. After years of research, the engineering company was comfortable that they knew what it would take to remediate the site and how much it would cost. They had the expertise to do it themselves so they felt they understood the risks and could handle the project because they weren't depending on anyone else's judgment or expertise. The property owners then paid the engineering company to accept legal responsibility for the cleanup. They had to put up a huge bond, but the result was a project where the property owners could finally get financing and move ahead with development because they and the lenders were no longer on the hook for unknown and unlimited environmental cleanup liability. The engineering company got the job done on time and under budget and made out like bandits. The lenders got their money back plus their exorbitant interest rate. The property owners got a project that was hugely profitable. And the local government got a huge boost in their tax base.
So, yes, it can be done. But it's not going to be done if industry, the government and local neighbors insist on a 1970s-era approach to a 21st century problem.