The MEC Vandalia Road site received coal-tar wastes in the 1950’s from the demolition of the Two Rivers Former Manufactured Gas Plant (FMGP) site in Des Moines. Wastes were disposed in an abandoned, clay-lined channel of Four Mile Creek just south of Vandalia Road on the south side of Pleasant Hill. MEC began investigation of the site in 1996. A chemical and biological treatment research program using an on-site land-treatment unit was initiated in 1998 and was discontinued in 2000. The site was enrolled in the LRP in September of 2002. Additional treatment of residual soil contamination in the former land-treatment unit using chemical oxidation was completed in October of 2004. From January through April 2005 stabilization of residual liquid waste in original channel disposal area was completed by augering-in cement. Stabilized soils were covered with a minimum of 2 feet of clean soil. A risk assessment revealed no unacceptable risk to soil other than disposal channel where wastes were stabilized, but were not eliminated. A limited area of on-site groundwater contamination has been identified. Groundwater monitoring has demonstrated stable or improving conditions. A continued decrease in groundwater contamination is anticipated due to the stabilization of the source material in the former channel area. An environmental protection easement prohibits excavation or installation of wells in the former channel area. A county ordinance further limits potential groundwater use.