U.S. Army Garrison Yuma Proving Ground/Kofa Firing Range Public Water System (PWS ID No. AZ0414367) failed to meet the drinking water maximum contaminant level ( MCL ) for arsenic since June 2007 to the present. EPA adminstrative order requires the U.S. Army Garrison at Yuma Proving Ground to provide EPA Region 9 with plans and schedules to meet the MCL for arsenic by June 2012.