Fourth Street Abandoned Refinery

Overview

A 27-acre oil refinery operated in Oklahoma City from the early 1940s through the early 1960s, leaving behind soil and groundwater contaminated with hazardous metals and organic chemicals. EPA added the site to the National Priorities List in 1989 and organized cleanup into three operable units covering sitewide concerns, source control, and groundwater. The site was deleted from the list on August 21, 2008, after cleanup goals were met.

Contaminants found in soil, sludge, and solid waste include metals such as lead, arsenic, barium, cadmium, and zinc, along with organic chemicals including benzene, trichloroethene, tetrachloroethene, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and pesticides like chlordane and aldrin. Groundwater contamination included benzene, trichloroethene, vinyl chloride, chloroform, and arsenic, among others.

Source control cleanup ran from September 1994 through March 1996. Workers excavated and stabilized contaminated materials, removed on-site structures, and hauled waste off-site. About 44,192 cubic yards of contaminated waste were neutralized and stabilized, with up to 70,000 cubic yards of treated sludge and 42,000 cubic yards of neutralized waste transported for proper disposal. Groundwater remediation began in July 1995 and ran through February 1997, followed by long-term monitoring. Contaminant levels dropped steadily, and by 2003 groundwater in the area was confirmed not to be used as a drinking water supply. EPA and the state stopped groundwater monitoring, and all monitoring wells were plugged in 2005. The Oklahoma Department of Environmental Quality (ODEQ) took over operation and maintenance in March 2006.

Human exposure is currently under control across the entire site. Contaminated groundwater migration has been stabilized, and there is no unacceptable discharge to surface water. A deed notice issued in June 2001 restricts the property to industrial and commercial uses and prohibits drilling of drinking water wells on or near the site. Two businesses now operate on the site, employing 53 people and generating an estimated $10.7 million in annual sales as of December 2024. EPA completed its most recent five-year review in September 2022, confirming the remedy continues to protect human health and the environment. A groundwater remedial investigation is estimated to begin between April and June 2026, and the next five-year review is estimated between May and July 2027.

Community members with questions can contact EPA's Community Involvement Coordinator or Remedial Project Manager. For state-related questions, contact ODEQ.