William Pigott came to Seattle from Ohio, New York, and Colorado in 1896. He ran several businesses selling and fabricating steel products for logging camps and logging railroads. With his partner Judge Elliott M. Wilson (d. 1927), Pigott incorporated Seattle Steel Co. in 1903. They constructed eight frame buildings on 55 acres of tideflats purchased from the Northern Pacific Railroad. The buildings housed a heating room, a scrap room, a rolling mill, and offices. Scrap steel was the principal feed stock. The Seattle Sunday Times hailed the plant as "Seattle's Little Pittsburgh." This mill became the first steel mill in the United States to offer workers an eight-hour day.
In 1905, Pigott incorporated Seattle Car Manufacturing Co. on the same property. This company moved to Renton in 1908 and was renamed Pacific Car and Foundry Co. in 1917.
In 1913, Seattle Steel merged with a San Francisco firm and became Pacific Coast Steel. The business grew to more than 500 employees in 1927. In 1930, Bethlehem Steel Co. purchased the mill, and operated it until 1985, when it was purchased by Carl E. Meitzen and Seattle Steel Co.