The Commodore Semiconductor Group site, which is located in Norristown, Montgomery County, Pennsylvania, was operated as a computer chip manufacturing facility from 1970 to 1993 by Commodore Business Machines. Waste solvents were stored in an underground concrete storage tank on site until 1975, when it was taken out of service. An unlined steel tank was installed next to the concrete one in 1975. Inspections conducted by the Pennsylvania Department of Environmental Protection indicated that both tanks leaked. The majority of residences in the area are connected to a privately-owned public water supply, however, a small number of individuals still have operational private wells.
This site was proposed to the National Priorities List of the most serious uncontrolled or abandoned hazardous waste sites, requiring long-term remedial action on January 22, 1987. The site was formally added to the list on October 4, 1989.