Ontario & British Columbia · CSA Z768-01

Phase 1 Environmental Site Assessment

A records-and-observation review that identifies potential site contamination before a transaction, financing decision or development application — performed by a Professional Engineer and Professional Geoscientist.

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Standard: CSA Z768-01 or O. Reg. 153/04the right one depends on purpose
Sampling: None at this stagerecords review and site observation only
Prepared by: P.Eng & P.Geoover 30 years' combined experience
Typical use: Financing & due diligenceoften a lender requirement

What a Phase 1 ESA is

The purpose is to identify potential site contamination by collecting current visually accessible evidence and reviewing background documents — not by sampling.

We provide Phase 1 and Phase 2 Environmental Site Assessment services in Ontario and British Columbia, performed by a Professional Engineer and Professional Geoscientist with over 30 years of combined environmental consulting and engineering experience. Assessments can follow the Canadian Standards Association's CSA Z768-01, or Ontario Regulation 153/04 and its amending regulation, O. Reg. 511/09, depending on the purpose of the report.

CSA-based Phase 1 reports are typically used to obtain financing or refinancing from banks, trustees and private lenders, and for due diligence in real estate transactions between buyers and sellers.

The assessment draws on historical records, aerial photographs, prior environmental reports, a site visit, and interviews with people familiar with the property's history, to build a picture of current and past land use on the site and neighbouring properties.

If the review identifies an Area of Potential Environmental Concern, the report will recommend whether a Phase 2 ESA — which does involve sampling — is warranted to confirm whether contamination is actually present.

When a Phase 1 is needed

Three situations that most often prompt one.

Financing or refinancingBanks, trustees and private lenders typically require a current Phase 1 before approving a mortgage secured against commercial or industrial property.

Real estate due diligenceBuyers and their advisors commission a Phase 1 before closing, to understand any environmental liability attached to the land.

Development or rezoningMunicipalities and provincial bodies often require a Phase 1 as part of a rezoning or permit application.

The Phase 1 ESA Process, Step by Step

Five stages, from records review to final report — typically completed in 2–3 weeks.

01 Records review Fire insurance plans, historical aerial photographs, city directories, and prior environmental reports are pulled and cross-referenced against the property's chain of title.

02 Regulatory database search Federal and provincial environmental databases are searched for the subject property and neighbouring sites, covering spills, storage tank registrations, and known contaminated sites.

03 Site reconnaissance A qualified environmental professional walks the property, documenting visible evidence of contamination, drainage patterns, staining, storage practices, and the condition of any tanks or drums.

04 Interviews Current and, where possible, previous owners or long-term site personnel are interviewed to capture institutional knowledge that doesn't appear in the written record.

05 Report and recommendation Findings are compiled into a signed and sealed report stating whether Recognized Environmental Conditions exist and, if so, whether a Phase 2 ESA is recommended.

What a Phase 1 ESA Report Is Good For

Beyond the three most common triggers above, a Phase 1 ESA report is routinely relied on for:

Mortgage renewal Lenders often require an updated Phase 1 if the property's last assessment is more than a few years old, or if the loan is being restructured.

Insurance underwriting Environmental liability insurers frequently request a current Phase 1 before issuing or renewing pollution liability coverage on commercial property.

Corporate transactions Mergers, acquisitions, and share purchases involving real property holdings typically include a Phase 1 as part of the buyer's due diligence package.

Government funding applications Grant and loan programs tied to redevelopment or brownfield remediation often require a Phase 1 as a condition of eligibility.

Estate settlement and property transfer Executors and trustees commission Phase 1 assessments before transferring or selling commercial and industrial property held in an estate.

Industrial and commercial leasing Landlords and tenants both use a Phase 1 to document baseline environmental conditions before a long-term industrial lease begins.

Related services

Environmental Site Assessment — Overview

Phase 1 ESAs by area

We work across Ontario, generally within 500 km of our Vaughan head office. Each area has its own page.

Common questions

Phase 1 ESA Questions

What does a Phase 1 ESA involve?

A review of background documents and current visually accessible evidence on the site — historical records, aerial photographs, prior environmental reports, a site visit, and interviews — to identify signs of actual or potential contamination. Physical sampling of soil, air or groundwater is not conducted at this stage.

Which standard applies in Ontario?

Two frameworks exist side by side: the Canadian Standards Association's CSA Z768-01, and Ontario Regulation 153/04. Which one applies depends on the purpose — CSA Z768 is typical for financing and transactions, while O. Reg. 153/04 governs filings such as a Record of Site Condition.

What happens if the Phase 1 finds a potential concern?

The report identifies Areas of Potential Environmental Concern and recommends whether a Phase 2 ESA is warranted to confirm, through actual sampling, whether contamination is present.

How long does a Phase 1 take?

Typically two to four weeks from engagement, depending on how quickly historical records and site access can be arranged.

Is the CSA standard changing?

Yes. A new edition of CSA Z768 is in development that will integrate climate change considerations into Phase 1 practice, including forward-looking climate data in the assessment of long-term site risk.

Buying, Financing or Developing?

Send us the property address and what the report is for — we'll confirm the scope and reply with a fixed quote, usually within one business day.

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