Established in 1851, American Tube Works was the earliest manufacturer of seamless brass tubing in the country. The brick buildings that exist today were part of modernization efforts by the company during the late nineteenth and early twentieth centuries. The company closed in the 1930s. The complex consisted of fifteen buildings adjacent to the Fitchburg division of the Boston & Maine Railroad and included several drawing mills, a rolling mill, a machine and pattern shop (c. 1890), and a foundry. Several buildings, including the two fronting Somerville Avenue, were constructed with steel frames and concrete floors, and most were one story with clerestory roofs, typical of the metal-working industry. Representative of an important and once flourishing metal industry in the Boston area, the complex now houses small businesses.