The WTS is not badly advised when it comes to commercial and legal matters. They know exactly what they are doing and pay a lot of money to very good lawyers, engineers, architects and construction specialists.
I cannot believe the WTS did not know that land they purchased was contaminated. There may be arguments about the extent of the problem or around the scope of some kind of prior disclosure but the WTS is very good at arguing the toss over details like this and winning.
IMHO no JW is going to wake up to TTATT on the basis that Jehovah should have warned them, I don't think it's much of a scandal or a cover up. Things like this happen all the time in large scale property development. I wouldn't expect any other multi-million dollar global corporate to act any differently.