Built in 1920 to operate a rock quarry in Napa, California, the company began manufacturing barges 18 years later. Following World War II, it switched to making vessel repair and scrapping. In 1955, the company was acquired by Kaiser Steel and returned to shipbuilding, but it closed once more in 1985. Sadly, Basalt Rock Shipyard is one of the hundreds of shipyards that exposed workers to asbestos during the last century. The mineral has many convenient properties, such as fire resistance, durability, resistance to chemical corrosion, and inability to conduct electricity. During World War II, up to 4.5 million people worked in shipyard occupations, which means that they have a high risk of developing a terrible disease today due to past asbestos exposure.