The Moss-American site comprises 88 acres including a former creosote facility and six miles of the Little Menomonee River, which is adjacent to the former facility. The Moss-American property is located at the intersection of Brown Deer and Granville Roads on Milwaukee's northwest side. About 65 acres are undeveloped Milwaukee County park land. About 23 acres are owned by the Union Pacific Railroad and are currently being used for industrial purposes.
From 1921 to 1976, Moss-American operated as a wood-preserving facility that treated railroad ties with a creosote and fuel-oil mixture. EPA environmental studies have concluded that previous site activities contaminated soil and ground water as well as sediment (mud) in the Little Menomonee River. Contaminants of concern include polychlorinated aromatic hydrocarbons and organic compounds such as benzene, toluene, ethyl benzene, and xylene.
Creosote is derived from coal tar. Naphthalene, an example of a PAH, is the most common ingredient in coal tar, and so it is also the most common ingredient in creosote. PAHs can often cause irritation and rashes to people with sensitive skin. Because river sediment is contaminated with PAHs, it is important for people to refrain from coming into contact with it.