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Application to change the PHAI Cleanup Criteria

As part of ongoing dialogue with regulators, Canadian Nuclear Laboratories (CNL) will revise its application to the Canadian Nuclear Safety Commission (CNSC) to amend the Cleanup Criteria for the Port Hope Area Initiative (PHAI).

This change will remove the reference to the uranium criterion (which will remain at 23 parts per million (ppm)) and propose an increase in the level for arsenic from 18 ppm to 56 ppm.

Amending the PHAI Cleanup Criteria will help to:

Reduce the number of properties requiring cleanup

Reduce the time spent and impact on properties requiring remediation

Avoid further delays and reduce overall cost

Avoid extensive impact
on the natural environment

Community concern is strong. 
In the first three years of residential cleanups, the Port Hope community expressed strong frustration with the timelines and extent of the cleanups in their neighborhoods. There is also growing concern that the PHAI will result in significant undesirable changes to the urban tree canopy, the preservation of which is important to many people.

Unrestricted land use remains the goal. 
The proposed new level will meet the intent of the Legal Agreement, allowing all properties to be used for “all current and foreseeable unrestricted uses.”

Collaboration continues. 
CNL will continue to work closely with the Municipality of Port Hope to ensure Council and staff are kept informed. Feedback from regulators such as the Health Canada is being incorporated as CNL follows the CNSC application and review process.

PHAI Cleanup Criteria Quick Facts

  • Historic low-level radioactive waste in the Port Hope area is cleaned up to meet the levels of contaminants set out in the criteria. Through experience remediating public and private properties in Port Hope since 2018, CNL has determined that the very conservative levels of arsenic and uranium in the PHAI Cleanup Criteria are resulting in more extensive and lengthy cleanups than originally anticipated. In addition, analysis has shown that the current criteria will create significant unintended project impacts, including a noticeable loss of trees in the municipality, unless it is changed.
  • This revised level of 56 ppm is based on the risk guideline calculated by Health Canada’s human health and ecological risk assessment model. Removing the proposal to change the CC level of uranium allows regulators to focus on the evaluation of arsenic which, as the only parameter mobile in soil, has the most impact on the extent of a cleanup.
  • In March 2020, CNL submitted an application to the CNSC to amend the PHAI Cleanup Criteria based on information gathered and experience gained from the first two years of cleanup work on residential properties. The application used an approach of applying risk-based information and weight of evidence to propose alternative cleanup criteria levels for both arsenic and uranium. CNL identified that the original, conservative criteria levels of 18 ppm for arsenic and 23 ppm for uranium resulted in unintended negative effects on the community and natural environment.


  • Many residents have expressed dissatisfaction with the length of time it has taken to clean up their properties caused, in part, by the need to “chase” arsenic to meet the very low criteria level. The broader community has raised concerns about the unintended impact of the project on the natural environment, including a significant loss of trees in urban Port Hope.
  • CNL believes the revised number of 56 ppm for arsenic will still assist in the reduction of cleanup times on properties in Port Hope and potentially exempt a number of properties from the PHAI cleanup, while still being protective of human health and the environment.

Participate in the Process

The original application was supported by an extensive awareness and engagement campaign to inform and solicit feedback from the public as well as Indigenous communities and organizations.

Once the CNSC has indicated the timing of a Commission hearing to consider CNL’s application, CNL will share CNSC information on how to participate in the licensing process.

CNL will continue to provide meaningful opportunities for Port Hope residents, key stakeholders and Indigenous communities and organizations to learn more and provide feedback on the proposed revision to the PHAI Cleanup Criteria. In keeping with public health precautions during the COVID-19 pandemic, participation may be online or by phone.

  • Engagement with Indigenous communities and organizations
  • Updates at Municipality of Port Hope Committee of the Whole meetings
  • Information sessions
  • Presentations to community groups and the real estate community
  • Advertising: newspaper, radio
  • Social media – follow us Facebook and Twitter

Learn how you can participate in a CNSC licensing hearing

Need more information?

Check back here often for more information and details as the process moves forward or contact us at or 905.885.0291 to speak with one of our experts.

Learn more about the application to change the PHAI Cleanup Criteria

PHAI Criteria Change Timeline

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or contact us for more information.

CNL Proposal to Change PHAI Cleanup Criteria
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