Addressing contaminated sites

Addressing federal contaminated sites does not necessarily involve clean up but it always ensures that risks at sites are managed to safeguard human health and the environment.

Depending on the risks and specific site characteristics, various methods and approaches can be used to address contamination. Examples include: active remediation, like removal and disposal of contamination in appropriate landfill; pump and treat systems to address groundwater contamination; and bioremediation (introduction of nutrients and microorganisms to break down the contamination), etc.

Some sites are better addressed by managing the risks through approaches such as restricting access to the site, changing the usage of the land, isolating the contaminants, etc.

How is a site remediated?

After a site assessment is completed, a remediation or risk management plan is developed for the site. The plan describes the various remediation alternatives under consideration and identifies the preferred option to reduce the risks to human health and the environment. The chosen remediation method is designed to address the unique conditions at the site where it will be implemented.

The custodian oversees the development of the remediation plan and works closely with consultants, contractors and trades people hired to design and implement it. Common remediation activities involve reducing exposure to dangerous contaminants by removing, destroying or containing them.

How long can it take to restore a contaminated site?

Remediating a contaminated site can be done within a day, or may require several years. Many sites have become contaminated because of decades of improper handling and storage of waste of various types. It can take many years to address the contamination contained at some of the largest and most complex contaminated sites.

The duration of remediation activities at a site can vary considerably depending on various factors:

  • the nature and extent of the contamination
  • site characteristics (geological, geochemical and hydrogeological conditions)
  • location (e.g., remote regions difficult to access)
  • weather conditions (e.g., harsh climate)
  • technological capacities
  • scientific knowledge
  • length of the field work season

Where can I find information about environmental assessments for remediation projects?

Prior to the new Canadian Environmental Assessment Act (CEAA 2012), the remediation of contaminated sites on federal lands required a federal environmental assessment.

Public access to information and records for environmental assessments of federal remediation activities that were subject to the previous Canadian Environmental Assessment Act can be found in the Canadian Environmental Assessment Archives (

Under CEAA 2012, there is no longer a mandatory requirement for a federal environmental assessment. However, the Minister of Environment and Climate Change can designate specific federal remediation activities and require a federal environmental assessment based on the potential for adverse environmental effects or public concern about those effects.

An evaluation of potential significant adverse environmental effects of proposed remediation activities on federal lands will still need to be conducted. If significant effects cannot be mitigated then a Cabinet Level decision would need to be made as to whether those effects could be justified in the circumstances. Federal authorities will be required to report to the public on these evaluation activities annually.

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