Deep secret: Military waste remains a Lake Superior mystery

A mystery lies scattered on the silty bottom of Lake Superior a few miles from Duluth Harbor. On seven occasions between 1959 and 1962, U.S. Army contractors dumped more than 1,400 steel barrels of classified material from Honeywell operations at the Twin Cities Army Ammunition Plant (TCAAP) in Arden Hills into the cold waters Lake Superior. The dumping solved two problems for the Army -- how to dispose of the waste economically and how to keep the contents secret.