Am I exposed to environmental contamination liability if I buy a property at an Ontario municipal tax sale?

Potentially, yes, and this is one of the risks that makes tax sale purchases meaningfully different from an ordinary resale. Ontario's environmental protection framework can attach responsibility to whoever currently owns or controls a property, in some circumstances regardless of who actually caused contamination in the past, so simply acquiring title through a tax sale does not automatically shield a new owner from that exposure.

This risk is amplified in a tax sale specifically because there is no cooperative seller to ask about past uses, no environmental representations in the tender documents, and often no interior or full-site access before you bid. A property with a history of industrial, commercial, or fuel-storage use, or one near a former gas station or dry cleaner, deserves particular caution, since visible condition alone will not tell you what may be in the soil or groundwater.

Where any red flags exist, or the property's history is unclear, an environmental site assessment before bidding - or at least a careful records review - is worth the cost relative to the risk of inheriting a contamination problem you cannot see.