Since the 1880's, the Campbell Shipyard site, adjacent to the Hilton San Diego Conventional Center in downtown San Diego, was used for industrial activities including shipbuilding, the manufacturing of bulk petroleum, and gas waste disposal. As a consequence the environment surrounding the site was heavily contaminated requiring extensive environmental remedial work to clean up the site for development.
The first phase of remedial work required treatment or removal of more than 60,00m3 of contaminated soil from the upland portion of the project site. However, when the basin was tested it was determined that the dredging and proper disposal of such a huge volume of hazardous material would be too costly. As a solution, it was proposed to construct a cap over the sediment to permanently separate the contaminated sediment from the marine environment.
The largest portion of the capped area comprised an engineered cap covering an area of more than 3 hectares.