Superfund Site Profile
The Arsenic Trioxide site is located in Richland and Sargent counties in southeastern North Dakota. It covers 26 townships (about 568 square miles) of sparsely populated farmland with a few small towns, including Lidgerwood, Wyndmere, Milnor and Hankinson. Historical use of arsenic-based grasshopper bait and naturally occurring sources contaminated groundwater in the shallow aquifer with arsenic. Following cleanup, EPA took the site off the Superfund program’s National Priorities List (NPL) in July 1996.