The Rose Park Sludge Pit sits in Salt Lake City, Utah, on what is now part of Rosewood Park. From the 1930s until 1957, the Utah Oil and Refining Company dumped acidic waste sludge into an unlined 5-acre pit, leaving waste up to 20 feet deep. That waste contaminated both soil and groundwater with hazardous chemicals. The site was added to the Superfund National Priorities List on September 8, 1983.
The main cleanup actions focused on containing the waste in place. Workers built a slurry wall around the pit to cut off the spread of contamination and protect groundwater. They also placed a clay cap over the pit and installed monitoring wells to track conditions over time. Construction ran in two phases, wrapping up on June 17, 1992. Operation and maintenance activities, including ongoing groundwater monitoring, have continued since July 1, 1985.
EPA deleted the site from the National Priorities List on June 30, 2003, after cleanup goals had been met. Human exposure across the entire site is currently under control, with no unacceptable exposure pathways identified. However, contaminated groundwater is still migrating beyond the original area, and not all cleanup goals tied to future land use have been fully achieved. The state performed the most recent five-year review on September 1, 2022, confirming that response actions continue to protect human health and the environment. The next review is estimated between September and November 2027.
Salt Lake City turned the site into an expansion of Rosewood Park. The project added parking, a dog park, a playground, exercise equipment, sidewalks, and landscaping. A nearby property to the west became a skate park. These additions also serve a practical cleanup purpose by keeping vehicles off the protective cap.
Community members with questions can contact the EPA Remedial Project Manager. For state-related questions, contact the Utah Department of Environmental Quality (UDEQ). Site records are available at the Utah Department of Environmental Quality in Salt Lake City and at the EPA Superfund Records Center in Denver.
