Sites with unmanageable ecological risk: federal contaminated sites advisory bulletin

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What if a contaminated site with unacceptable ecological risk cannot be remediated or risk managed?


Once a federal site is considered contaminated1, a federal custodian may implement either of the options outlined below2.

  1. A Remediation Strategy that uses one of the following approaches to remediate (i.e. remove or reduce contamination):
    • The Guideline Approach to meet the Canadian Council of Ministers of the Environment (CCME) Tier 1 or Tier 2 remediation objectives3; or,
    • The Risk Assessment Approach to assess if contamination poses, or is likely to pose, an immediate or long-term hazard to human health or the environment and, if necessary, develop and meet Site Specific Target Levels (CCME Tier 3).
  2. A Risk Management Strategy that integrates the remediation strategy (above) with technical, political, legal, social and economic considerations to develop risk reduction and prevention strategies, thereby minimizing exposure to contamination.

Human health and ecological risk assessments help to inform whether, and to what extent, remediation and/or other risk management measures are warranted. If a detailed (or more refined) risk assessment establishes that existing contamination poses an unacceptable risk to human or ecological receptors at the site, contamination must be addressed via remediation (e.g., excavation) and/or risk management activities (e.g., engineering controls).

Standard approach

The standard approach outlined below should only be applied to contaminated sites that have:

  • Undergone a detailed (or more refined) risk assessment; or
  • Considered innovative, feasible approaches to remediation/risk management.

When unacceptable ecological risk at a FCSAP site cannot be resolved through remediation or risk management activities, further FCSAP expenditures may not be warranted and site closure may not be possible.

In the case of a FCSAP contaminated site with unacceptable residual ecological risk, all site documentation should clearly outline:

  • The course of action taken at the site to date;
  • The risks remaining at the site (e.g., nature of contamination, receptors of concern);
  • A cost-benefit analysis and/or rationale as to why no further activities to reduce these risks will be undertaken.

Please note that while a site with unacceptable residual risk may not be able to achieve site closure, the FCSAP Site Closure Tool may still assist Federal Custodians in capturing the information above, in addition to other site-specific details.  

For additional guidance on how to address FCSAP sites where site closure is not possible (e.g., due to ongoing sources of contamination, or financial/technical constraints), the custodian may wish to contact their Departmental Headquarter Lead to discuss the path forward at the site (e.g., as it pertains to residual liability, safety concerns, ongoing monitoring).

The custodian should seek advice from FCSAP Regional Expert Support Departments who may provide additional site-specific comments in order to address contamination and unacceptable residual risk at these sites.

The custodian should also inform FCSAP Regional Expert Support Departments should site closure not be possible, and contact the FCSAP Secretariat in order to discuss the status of this site with regard to the FCSAP Priority List.



FCSAP Expert Support provides the above information in accordance with the FCSAP and associated guidelines and policies.  This is in no way to be interpreted as any type of approval, authorization, or release from requirements to comply with federal statutes and regulations.  If you have any questions or concerns, please e-mail:, or contact your regional FCSAP Expert Support.

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