The historic low-level radioactive waste and contaminated soil, located at various sites in the Municipality of Port Hope, are a consequence of past practices involving the refining of radium and uranium by a former federal Crown Corporation, Eldorado Nuclear Limited, and its private-sector predecessors. These waste materials contain radium-226, uranium, arsenic and other contaminants resulting from the refining process. The original Eldorado refining operation and plant were established in the 1930s without consultation with Indigenous peoples of the area.
In the Port Hope, the waste was placed at the Welcome Waste Management Facility, which was closed in 1955 and at various locations throughout the urban area. In the mid-1950s waste management operations moved approximately 13 km west to Port Granby Residue Area in Clarke Township, now Municipality of Clarington.
As part of the Port Hope Project the historic waste was removed from the Welcome facility and relocated to the newly built Port Hope Long-Term Waste Management Facility. Waste placed at the former Port Granby site has been relocated and safely stored through the Port Granby Project.