There are two dimensions to this. This largely would actually fall under provincial jurisdiction, under provincial legislation.
The exceptions would be if it involved a CEPA toxic substance and there were some specific regulatory requirement around that.
The other dimension of this is, of course, is CEPA part 9, which is if it was on federal land, then potentially the Government of Canada could do something about it, but, of course, to date there are virtually no rules under CEPA around that and, indeed, the commissioner of the environment and sustainable development has at some length described in detail the problems around the identification of contaminated sites, even on federal lands, and the scale of the problem just within the federal jurisdiction.
The problem at the moment is that we have made virtually no use of the provisions that exist under the act.