Navigating Risk Assessment in Ontario: An Overview of Ontario Regulation 153/04 Risk Assessments and Due Diligence Risk Assessments
Navigating Risk Assessment in Ontario: An Overview of Ontario Regulation 153/04 Risk Assessments and Due Diligence Risk Assessments
What is a Risk Assessment?
A risk assessment (RA) is an evaluation which estimates the likelihood and magnitude of adverse effects resulting from exposure of both human and ecological receptors to environmental contaminants.
In Ontario, contaminated sites RAs can be conducted under the provincial Record of Site Condition (RSC) regulatory process (i.e., the Tier 2 Modified Generic RA or Tier 3 RA streams) laid out in the RSC Regulation (O. Reg. 153/04), and in a non-regulatory environment (e.g., due diligence risk assessment).
Types of Risk Assessments in Ontario
Risk Assessments under O. Reg 153/04
In Ontario, the RSC regulation (O. Reg. 153/04) under the provincial Environmental Protection Act, was established by the Ministry of the Environment Conservation and Parks (MECP) to promote redevelopment of Brownfield sites in a way that is protective of human and ecological health.
Property owners may be required to have an RSC filed for one or more of the following reasons:
- Mandated by O. Reg. 153/04 if redeveloping the site to a more sensitive land use (e.g., from industrial use to residential use);
- Municipalities may occasionally require it for a specific property going through the planning approval process;
- Sale/Purchase of the property and one of the parties requires it; and/or,
- Property is undergoing financing and the lender is requesting an RSC.
Under O. Reg.153/04, concentrations of chemicals in soil and groundwater are compared to the generic Site Condition Standards (SCS) protective of human health and ecological receptors. If concentrations meet the SCS, an RSC can be filed for the property. If exceedances are identified, and remediation of soil or groundwater to meet the SCS is not technically or economically feasible, a property owner may opt to proceed with an RA through O. Reg. 153/04, by which alternative standards may be established (i.e., property-specific standards (PSSs)), often with requirements for implementing risk management measures (RMMs) to mitigate risks while leaving contamination in place. The two primary types of RAs submitted under O. Reg. 153/04 are:
- Tier 2 Modified Generic Risk Assessment (MGRA) – A Qualified Person for Risk Assessment (QPRA) can modify the SCS using the Ministry-approved MGRA model to generate PSSs that are based on the unique conditions of the site which may be numerically higher while continuing to be protective. The preparation and review process of an MGRA is often fast and cost effective; however, a very limited number of sites can be assessed using this approach due to strict data requirements and the limited number of RMMs offered by the MGRA model to mitigate potential risks.
- Tier 3 RA – A QPRA can develop PSSs through a traditional RA based on the specific conditions of the site. This offers greater flexibility but is more time and resource-intensive, both for the proponent and for Ministry review/decision-making.
Non-Regulatory Risk Assessments
If an RSC is not required or desired, the property owner or other interested parties can still retain a QPRA to complete a due diligence risk assessment (DDRA). These DDRAs are completed “in the spirit of O. Reg. 153/04” and are presented in a streamlined report that can be tailored to meet the intended objectives. They provide excellent value for assessing risks and providing recommendations for RMMs, using approved Ministry approaches, without the longer timeline or associated costs, as one does not have to formally go through the lengthy Ministry review process.
DDRAs are commonly conducted when one wishes to:
- Divest or acquire a potentially contaminated property (i.e., property sale/financial purposes);
- Address legal liability and compensation issues between the property owner and other stakeholders; or,
- Evaluate potential health risks to on-site workers or the surrounding community arising from any existing contamination.
What Type of Risk Assessment Do I Need for my Site?
The flow chart below presents an overview of the steps determining the appropriate RA for a Site.
Need a Risk Assessment for Your Site?
Intrinsik has extensive experience conducting O. Reg. 153/04 RAs, as well as DDRAs to support financing, or the purchase or sale of properties. Our reports are presented in a streamlined format to improve readability and transparency.
For more information or assistance with risk assessment projects, please contact one of our QPRAs: Adam Safruk at or Glenn Ferguson at .