The Purity Oil Sales, Inc. site is a 7-acre former used oil reprocessing facility in Malaga, California, near Fresno. It operated from 1934 to 1974, and improper storage and disposal of oil and refining byproducts contaminated both soil and groundwater. EPA added the site to the National Priorities List (NPL) in September 1983, and a remedial investigation began in January 1984.
Contamination affects two main areas: groundwater and soil. Groundwater contains volatile organic compounds (VOCs) including benzene, trichloroethene, vinyl chloride, and carbon tetrachloride, plus the metals arsenic, iron, and manganese. Soil contamination is broader and includes VOCs, pesticides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and heavy metals such as lead, mercury, arsenic, cadmium, and chromium. Over 100 chemical substances have been identified as contaminants of concern at the site.
Cleanup has been organized into two operable units. For groundwater, EPA installed extraction wells, air stripping technology, and iron and manganese filters starting in 1995, and provided alternate water supplies to affected residents. EPA is considering updating the groundwater remedy after finding that site conditions limited the pumping and treatment system. For soils, EPA installed an impermeable cover with a soil vapor extraction (SVE) system and enclosed the nearby North Central Canal in a concrete pipe, completing that work in 1998. Some nearby families relocated temporarily or permanently during construction. Major remedial construction across the site was finished in September 2012, though operation and maintenance continues in both operable units.
Human exposure across the entire site is currently under control, with no unacceptable exposure pathways identified. Groundwater migration is also under control, with contaminated groundwater stabilized and no unacceptable discharge to surface water. The most recent five-year review, completed in September 2021, found that current response actions protect human health and the environment in the short term. Continued protectiveness requires developing an institutional control plan and resuming the soil gas sampling program. The site has not been deleted from the NPL.
Community members can get involved through the upcoming sixth Five-Year Review, which EPA plans to complete by September 30, 2026. The review will include a site inspection, a look at new laws that could affect cleanup, and coordination with stakeholders. The completed report will be posted on the site webpage and sent to EPA's Superfund Records Center in San Francisco. Direct questions can be directed to the Community Involvement Coordinator or Remedial Project Manager.
