Posted on July 8, 2026
Hamilton Port used environmental dredging and a containment structure to isolate contaminated sediments in Lake Ontario. The 6.2-hectare box received 615 thousand cubic meters of toxic sludge. The final cover of the work is scheduled for 2027. The project shows how old industrial pollution requires long and careful solutions.
Canada built a 6.2-hectare engineering box within Hamilton Port, in Lake Ontario, to contain 615 thousand cubic meters of contaminated sediments. The toxic sludge accumulated at the bottom of the water after decades of industrial pollution.
The problem was not visible on the surface. The contamination was mixed with the sludge and sand at the port’s bed, where the material could spread if removed without control. Randle Reef, the portal of the port’s decontamination project, outlined the steps used to trap this pollution within a closed area.
The work began in 2015 and has already completed the sediment containment phase. The final environmental cover is still scheduled for 2027, meaning the site’s recovery is ongoing.
The contaminated sludge remained hidden at the bottom of Hamilton Port for decades
What needed to be treated was not floating garbage. Contaminated sediments are sludge, sand, and small particles accumulated at the bottom, capable of holding industrial residues for many years.
In Randle Reef, the pollution formed from industrial activities that began in the 19th century. The area contains toxic compounds called polycyclic aromatic hydrocarbons, linked to health risks and water quality issues.
Handling this type of sludge requires care. When the bottom is disturbed, the particles can return to the water and reach other parts of the port. Therefore, the Canadian project did not treat the dredging as a common land removal.
A 6.2-hectare box was assembled in the water to contain industrial pollution
The first stage created a submerged containment structure over the most contaminated area of the port. It functions like a large vault built on the waterbed itself, designed to keep the hazardous sludge in a confined space.
The structure received two steel walls and was formed by 3,400 steel beams, ranging from 23 to 33 meters in size. The pieces were driven into the bed to form a barrier capable of holding the contaminated sediments.
The solution avoided the direct removal of the most hazardous sludge. Instead of moving this material elsewhere, engineering sealed the area where it was already accumulated and created space to receive sediment removed from neighboring parts.
