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Phase 1 Environmental Site Assessment in Ontario

Reviewed by Fisher Engineering’s environmental QPs: David Fisher, P.Eng., C.Chem. (QP) · Bernard Chan, P.Eng., C.Chem. (QP) · Marius Voinea, P.Geo., B.Sc. (QP). Meet the team

Phase 1 Environmental Site Assessment

There are two distinct types of Phase 1. In Ontario, the difference between a Phase 1 Canadian Standards Association (CSA) and a Phase 1 Record of Site Condition (RSC) is essentially the difference between “private due diligence” and “regulatory law.”
While both involve a non-intrusive investigation of a property’s history and current state, they serve different purposes and follow different rulebooks.

Phase 1 CSA – Due Diligence

The CSA Z768-01 standard is the “business” version of an environmental assessment.

  • Goal: To identify “Areas of Potential Environmental Concern” (APECs) so a buyer or lender knows if they are inheriting a mess. 
  • Flexibility: The Qualified Person (QP) can use their judgment to determine which records to check. If the property is clearly a farm with no history of chemicals, the scope might be lighter.
  • Confidentiality: The report stays between you, your consultant, and your lender.
Phase 1 Environmental Site Assessment

Phase 1 RSC – Regulatory Law

The O. Reg. 153/04 standard is a legal document required by the Ontario Ministry of the Environment, Conservation and Parks (MECP). 

  • Goal: To prove a site is safe for a more “sensitive” use (like turning an old warehouse into condos).
  • The “Checklist”: Unlike the CSA version, the RSC version is not flexible. The law dictates exactly how many years of title search are required (usually 25+), which databases must be checked (often 60+), and who must be interviewed. 
  • Mandatory Phase 2: If a Phase 1 RSC identifies a “Potentially Contaminating Activity” (PCA), you must proceed to a Phase 2 ESA (soil/water testing) to file the Record of Site Condition. 
  • Public Record: Once filed, the RSC is posted on the Environmental Site Registry for anyone to see.

Note: 

  1. You cannot easily “upgrade” a CSA report to an RSC report later. If there is even a small chance you will need an RSC (e.g., for future rezoning), it is often cheaper to do it to the RSC standard from the start. 
  2. Phase 1 reports, either CSA or RSC, are typically valid for 18 months from time of assessment.

Phase 1 ESA FAQ

What is a Phase 1 Environmental Site Assessment?

A Phase 1 ESA is a records-and-site review that looks for past or present uses that could have contaminated a property. No soil or water is sampled. In Ontario it is done either to CSA Z768-01 for due diligence and financing, or to O. Reg. 153/04 when a Record of Site Condition may be needed.

A standard Phase 1 ESA report is usually ready in about 15 business days. If you are working toward a closing or financing date, we also offer 10-day and 5-day rush turnaround at a premium. Tell us your deadline when you request a quote.

Yes. Your first reliance letter is included with the Phase 1 report, as long as it is issued within six months of the report. Any additional reliance letters are available for an extra fee.