Randle Reef: Hamilton Harbour Area of Concern

Located in the southwest corner of Hamilton Harbour on Lake Ontario, Randle Reef is the largest contaminated sediment site on the Canadian side of the Great Lakes. About 60 hectares in total, it contains about 615,000 cubic meters of polycyclic aromatic hydrocarbons (PAHs) contaminated sediment—enough to fill a hockey rink nearly three times over. These carcinogenic toxins are the result of years of industrial pollution from multiple sources dating back to the 1800s.

Canada–U.S. Great Lakes Water Quality Agreement

In 1987, Canada and the United States identified 43 areas with high levels of environmental harm: 12 were Canadian and 5 were shared bi-nationally. The 2012 Great Lakes Water Quality Agreement reaffirms both countries’ commitments to restoring water quality and ecosystem health in the Great Lakes Areas of Concern.

Remediation of Randle Reef

In 2015, a $138.9 million project to clean up the reef began. It is estimated the project will generate approximately $167 million in economic benefits for the local community, create jobs, grow business development and generate tourism.

The completed project is also a key step in removing Hamilton Harbour from the list of Great Lakes Areas of Concern.

This three-stage project is led by Environment and Climate Change Canada and is unique for its funding approach:

Stage 1: Construction of an in-water, double-walled engineered containment facility (ECF) over the most contaminated sediment in the harbour. This structure consists of 3,400 steel beams of 23 to 33 metres in length inserted into the harbour floor.

Stage 2: Contaminated sediment surrounding the ECF was dredged from the harbour and placed into the structure. Any remaining contaminated sediment outside the ECF was managed in place using an isolation cap. With the completion of Stage 2, all of the contaminated sediment at the Randle Reef site has been safely and successfully managed. 

Stage 3: The final phase, scheduled to be completed by 2024, will involve placing a multi-layered environmental top on the ECF and transferring responsibility for the facility to the Hamilton⁠–Oshawa Port Authority to provide new valuable port lands.

Community involvement

Community members and stakeholders have been integral to cleaning up Randle Reef. Throughout the project, three levels of government, academia, industry and local stakeholders contributed to the development of a remedial plan. The project also brings together a dedicated multi-disciplinary team of experts ranging from engineers to scientists, project managers to meteorologists.

This approach of managing contaminated sediment in an engineered containment facility is a first in Canada. The project also ranked third on the Project Management Institute’s list of the top 10 influential projects in Canada for 2020.  In 2021, the project received an award from the Canadian Brownfields Network. 


Browse through the following videos highlighting the progress made in Stages 1 and 2 of the Randle Reef Remediation Project.

Related links

Page details

Date modified: