Madam Chair, that's a great question.
A contaminated site in the Transport Canada portfolio would be lands owned within the Transport Canada portfolio and have a contamination from historic activity. Often airports have PFAS, that foam that was used in firefighting drills, and often petroleum products.
In the case where a railcar goes off and there's a rail accident and spillage of a product, it would be the responsibility of the rail carrier and the shipper to clean up and remediate the site.