The United States should not expand nuclear energy use, at least until the federal government can make up for the harms caused by previous nuclear projects, U.S. Rep. Cori Bush of Missouri said at a congressional hearing in Washington, D.C., on Thursday.

Nuclear waste stored outside St. Louis was found to pose a risk to nearby Coldwater Creek as early as 1949. The contaminated creek will finally have warning signs almost 75 years later.

U.S. Rep. Cori Bush requested the Government Accountability Office evaluate the cleanup of the St. Louis County site contaminated by radioactive waste from the Manhattan Project. It found government costs have soared, from $177 million to $406 million in just seven years.