Could it be a similar situation like when someone buys a house? You do an inspection, and if you find anything wrong, you tell the current owners to fix it before you buy it
SW has such a huge headache on its hands from an acquisition they made years ago, because that company they bought made lead paint, now SW is responsible for for all of the liability stemming from that.
Now, is going to purchase the land, I could see them wanting property that is free and clear of any potential problems, like contaminated groundwater, that the corporation may be held liable for, even if it was due to the previous owners.
But, this is just my speculation.