Abandoned Brownfield Building

The term “brownfields” refers to properties, often former industrial or commercial sites, that are vacant or underutilized because of real or perceived environmental contamination as a result of historical land use practices. Many of these sites are located on prime land, ripe for redevelopment, including:

  • Gas Stations and Other Fuel Storage
  • Factories
  • Dry Cleaners
  • Former Schools
  • Waterfront properties (port lands) formerly used for industrial or commercial activities.

As of 2015, approximately 72% of Ontario’s RSCs are filed in the GTA and Ottawa. This disproportion is attributed to stronger market pressures and the fact that these areas are historically the most industrialized parts of the province. (De Sousa, 2017)

Brownfields can pose health and safety risks for both the surrounding community and the environment. Although it can be costly for the communities where they are located, brownfields can be remediated in order to meet health, safety, and environmental requirements to allow redevelopment for more sensitive property uses (e.g. new condominiums).

Maximizing Value

Brownfields present both potential liabilities and opportunities for current owners and developers. Well-located brownfield sites can be in areas where redevelopment would otherwise be desirable and may already include local infrastructure such as roads and utilities, saving the need to build these from scratch.

While the cost of developing brownfields can be significantly greater than greenfields, many cities and municipalities across Canada have implemented urban intensification strategies that provide tax incentive programs or breaks in development charges. Redevelopment can have an enormously positive impact on the surrounding community as brownfields often make up a large proportion of the available real estate.


When presented with a contaminated site, owners and developers have two options:

Remediate or Conduct a Risk Assessment.

In order to allow a brownfield to be used for a more sensitive property use (i.e. industrial to residential), a Record of Site Condition (RSC) is required under Ontario Regulation (O.Reg.) 153/04, as amended.

Typically, the minimum requirements are:

  • Phase One Environmental Site Assessment (ESA)
  • Phase Two Environmental Site Assessment
  • Remediation and/or Risk Assessment

Each RSC must be filed by a Qualified Person (QP Designation under O.Reg. 153/04)

If assessment shows concentrations of contaminants in on-site soil or groundwater that exceed the applicable Site Condition Standards in O.Reg. 153/04, as amended, and redevelopment to a more sensitive land use is planned, then the site is considered a “brownfield”.

Phase I / One ESA

Typically, a Phase I ESA (CSA Standard) is required in order to fulfil the due diligence requirement relating to refinancing or renewing the mortgage on a property, completing a property transaction, or to simply identify the possibility that an environmental liability may exist in relation to the site. In cases where an RSC is required for redevelopment to a more sensitive land use, a Phase One ESA (different than a Phase I ESA) must be completed according to O.Reg. 153/04 (as amended) protocols.

The objective of the Phase I / One ESA is to identify any Areas of Potential Environmental Concern (APECs) at the site which may pose a hazard to humans or the environment. In some cases, APECs may have a significant impact on the value of the site.

Phase II / Two ESA

Phase II Remediation (excavating soil)

The purpose of a Phase II / Two ESA is to investigate areas of potential environmental concern (APECs), identified during the Phase I / One ESA. A Phase II ESA usually consists of drilling boreholes, installing monitoring wells, collecting soil and groundwater samples, and conducting chemical testing on selected soil and groundwater samples. A Phase Two ESA (completed following O.Reg. 153/04 (as amended) protocols in support of an RSC submission) will include all Phase II ESA elements, in addition to a more detailed background review, set of interviews, and rigorous sampling methodology. In both cases, analytical data pertaining to soil and groundwater quality will be compared against applicable provincial Site Condition Standards to verify the presence or absence of on-site contamination.

If a Phase Two ESA identifies soil and/or groundwater contamination (i.e. concentrations above generic Site Condition Standards) at the site and is completed in support of an RSC submission, it must be addressed by either conducting remediation or a risk assessment.

Value of ESAs and Remediation to Property Owner/Lender

  • Understanding and accounting of environmental liabilities associated with a property
  • Catch Potentially Contaminating Activities (PCAs) before they can cause APECs, thereby reducing or eliminating future remediation costs
  • Ensure “saleability” of property
  • Reduce risks to building occupants
  • Allow for redevelopment and/or renovation
Modern Office Building Exterior

The McIntosh Perry Advantage

Our Sustainable Communities team has been conducting Environmental Site Assessments across Canada for more than 25 years. Projects have been completed for both new sites and existing developments of all types, ranging from commercial/industrial developments or subdivisions, high-rises for private developers, to large tracts of remote land for public sector clients. Whether it’s a simple due diligence Phase I ESA or a full Record of Site Condition, McIntosh Perry’s team of qualified professionals has the expertise you need.

Have questions about the ESA process or how our Environmental Engineering Services team can help your project? Reach out to us! We’d be happy to chat with you.


Mark Priddle, Vice President - Sustainable Communities

Mark Priddle – Vice President, Sustainable Communities

You have been redirected to McIntosh Perry, the associated Canadian firm of BLN