Basalt Rock Company

Basalt Rock Company was a multifaceted industrial operation that was founded in 1920. The company started as a rock quarrying operation located a few miles south of Napa, California near the Napa River. It later branched out into the ship building business in 1941 when it started building ships for the U.S. Navy for use during World War II. Following the war, the plant built 30 miles of pipe for the City of Napa's pipeline from Lake Hennessey.

In 1950, the company took title of a cement plant formally owned by Standard Portland Cement Company in what is now American Canyon, California. The cement plant remained in operation until 1978. The city is now in the process of evaluating the plant for future use.

The company's steel making plant was purchased by Kaiser Steel in 1955. The plant changed hands again in 1988 when it was purchased by Oregon Steel Mills and remained in operation as Napa Pipe until 2004. Developers have proposed turning the site into a housing development however thus far, they've faced strong opposition and controversy over the project.

The rock and sand portion of the company was purchased by the Dillingham Corporation in the early 1970s. It was acquired by Syar Industries in 1986, and presently remains in operation. In 2013 Syar announced that it was applying for permits to double the output of the quarry from 1 million to 2 million tons of aggregate.