Financed by San Francisco capitalists, industry began to move beyond the boundaries of San Francisco in the 1850s. Industrial growth in the East Bay led to the development of a number of working-class communities along the San Joaquin River, including Martinez, Bay Point and Pittsburg. A case study of the development of Pittsburg, California demonstrates the critical role heavy industry has played in the suburbanization of the San Francisco Bay Area. The mixed land use, racial heterogeneity and working-class character of industrial suburbs such as Pittsburg challenge the widely held belief that American suburbs in general and Bay Area suburbs in particular are solely residential enclaves of white, middle-class families. Disproportionately polluted and poor, industrial suburbs serve as economic engines used to fuel the outward growth of American cities.