Also known as San Francisco Naval Shipyards, this company was founded in 1870 and covered 638 acres of waterfront at Hunters Point in the southeast corner of the city. Initially, Hunters Point Naval Shipyard consisted of two graving docks. It was subsequently purchased and expanded by the Union Iron Works. Sadly, the workers were exposed to asbestos every day, as they had to handle toxic materials to build the ships. By far, asbestos insulation was the most common harmful product used to construct the vessels, and it would come in numerous forms, such as block insulation, pipe insulation, duct insulation, and boiler insulation. Employees would also be exposed to asbestos by inhaling and ingesting the toxic fibers released by various work tasks.