As I mentioned, I'm new to expressions, I pieced it together and this works fine:
=IIf([DeptAdmin]=True,"Administration ") & IIf([DeptCommSrvc]=True,"CommSrvc ") & IIf([DeptElect]=True,"Electri c") & IIf([DeptFin]=True,"Finance ") & IIf([DeptFire]=True,"Fire ") & IIf([DeptPolice]=True,"Police...