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EPA in Missouri

West Lake Landfill Contamination

In 1973, about 8,700 tons of leached barium sulfate cake residue was mixed with 39,000 tons of soil and deposited in the West Lake Landfill as fill material during landfill operations.

In 1990, EPA listed the site on the National Priorities List. The agency listed the entirety of the 200-acre West Lake Landfill due to the presence of radioactive waste in an area now known as Operable Unit 1 (OU-1). The portion of the landfill that does not contain radiological material is now known as Operable Unit 2 (OU-2). The adjacent Bridgeton Landfill remains under the oversight of the Missouri Department of Natural Resources. Link to West Lake Landfill site map.

Within OU-1, radioactive material has been found in two areas. At the time of the 2000 Remedial Investigation, Area 1 encompassed approximately 10 acres southeast of the main entrance road to the West Lake Landfill property. Area 2 encompassed approximately 30 acres along the northern boundary of the West Lake Landfill property. Additional investigations performed in Area 1 throughout 2014 and 2015 have improved our understanding of the OU-1 boundary.

In 2008, EPA issued a Record of Decision (ROD), which documented EPA’s remedial decision to install an engineered cap over the landfill to prevent future exposure to, and off-site migration of, the wastes contained at the West Lake Landfill. In 2010, EPA began reevaluating the 2008 ROD, and has expanded site characterization work and assessments.

From 2014 to 2015, EPA performed air monitoring at five off-site locations surrounding the landfill to measure levels of radiological contaminants and volatile organic compounds. EPA performed this air monitoring to establish a baseline level against which future samples could be compared during any on-site excavation or site work. This yearlong air monitoring effort demonstrated that air quality in the surrounding communities is similar to what is found throughout the St. Louis metro area.