The Dutchtown Treatment Plant is a 5-acre former oil refinery and waste oil reclamation facility in Ascension Parish, Louisiana. It operated from the mid-1960s through the 1980s, contaminating soil and groundwater with hazardous chemicals. Louisiana ordered operations suspended in 1983, and the site was declared abandoned in 1984. EPA placed it on the National Priorities List (NPL) in 1987 and deleted it in 1999 after cleanup goals were met.
The three contaminants of concern are benzene, ethylbenzene, and styrene, all found in groundwater across the entire site. EPA identified these chemicals because they pose unacceptable risks to human health or the environment based on the amounts present and potential effects from contact with them. Contaminated soil also poses health risks through ingestion or direct contact, though the groundwater exposure pathway is considered incomplete because contaminated groundwater is not used as drinking water.
Cleanup happened in stages. Emergency removals in 1987 and 1991 pulled nearly 450,000 gallons of waste oil and 3.5 million gallons of stormwater from the site. Between 1997 and 1998, workers installed clay caps over contaminated areas, put up a fence, closed a residential well, and placed institutional controls on land use. EPA's Record of Decision selecting the final remedy was issued in June 1994. The remedy also includes temporary water supply replacement and long-term groundwater monitoring every three years.
EPA's most recent Five-Year Review, completed March 16, 2021, found the remedy remains protective of human health and the environment. Human exposure is under control, groundwater contamination is stabilized in its original area, and all required land-use restrictions are in place. About 4,000 people live within three miles of the site. The site achieved sitewide ready for anticipated reuse status on October 10, 2007, and operation and maintenance activities have continued under EPA oversight since December 1997. Sources differ on the date of the most recent five-year review: one states it was completed March 16, 2021, and another states March 24, 2026.
Community members with questions can reach the EPA Community Involvement Coordinator or the Remedial Project Manager. For state-related questions, contact the Louisiana Department of Environmental Quality. Site records are available for public review at the Ascension Parish Library in Gonzales, Louisiana.
