When is a Phase 2 Environmental Site Assessment required after a Phase 1 flags a concern in Ontario?

A Phase 2 Environmental Site Assessment becomes the next step when a Phase 1 identifies a "potentially contaminating activity" or a data gap significant enough that it can't be ruled out through records and a site visit alone. Unlike a Phase 1, a Phase 2 involves actual physical investigation: drilling boreholes, installing monitoring wells, and collecting soil and groundwater samples that are then tested against applicable environmental standards for the property's intended use.

Common triggers include a documented history of fuel storage, industrial operations, waste disposal, or agricultural chemical handling on the site or on adjacent land where contamination could have migrated. A Phase 2 is also the standard route toward filing a Record of Site Condition where a change of use requires one, since a formal RSC needs actual sampling data behind it, not just a records review. Because Phase 2 work takes longer and costs more than a Phase 1, and results can materially affect a purchase price or even the viability of a deal, buyers should negotiate enough time in their agreement to complete it and decide how to proceed before conditions are waived.