I have worked in this field for over 30 years and I can only see one area where that would occur, and that's in the provisions of the federal Fisheries Act. Someone could pursue a dual action in the case of a deleterious substance--to use the federal legislation--that was put into waters that have fisheries in them. You could pursue it through me under the Ontario Water Resources Act, and pursue it conceptually through the federal commissioner and the Fisheries Act.
Aside from those pieces of legislation, the jurisdictions are pretty discrete, and I'm not aware of another area where there would be a conflict. Many of the other things only apply on federal lines where our legislation doesn't apply.