AbstractIdentification of a new contaminant is rare. When low levels of the highly soluble perchlorate (C104) cation were implicated in thyroid disorders, the Navy focused its cleanup effort at the former weapons plant at McGregor, Texas, on identification of sources, fate and transport, and application of heretofore unknown treatment technology to solve the problem while keeping a concerned public totally involved and informed. Since this article was written, extensive strides have been made in in‐situ anaerobic bioremediation of perchlorate, which should replace ex‐situ treatment as the probable final solut