Millions Paid for Contaminated Land

Over the years Waste Management (WM)  has paid millions of dollars to by land that has been contaminated by leachate impact groundwater. For years the groundwater has been contaminated by leachate leaking from the Carp Road dump. Slowly this contamination has spread off site to land down slope from the dump. Under provincial government regulation WM must clean up this contamination or buy the land so it can monitor the rate of contamination. Therefore WM has purchased nearly 140 acres of contaminated land. It seems that seems it is okay to contaminate your own land but if you impact your neighbour you just have to buy his land and everything is okay. How much more land will need to be purchased??