The 7-acre Shenandoah Stables Site is located near Moscow Mills, Missouri. In 1971, a waste oil hauler sprayed a horse arena on site with dioxin-contaminated oil to control dust. Over 40 horses died and people became ill after the spraying. The same year, the contaminated soil was excavated and used as fill material in a new highway. More soil was removed from the arena and placed in a swampy area on the site in 1972. Following these actions, the soil at the arena remained contaminated. Site cleanup was completed in 1997. EPA removed the site from the Superfund program’s National Priorities List (NPL) in 2001.