AT APPROXIMATELY 10PM A ROOF FALL WAS DISCOVEREDBY SECTION FORMAN ON 004 SECTION, 4 LEFT MAIN ATSS 20401. THE FALL MEASURED 180'L X 18'W X 5'H. THE AREA WILL NOT BE CLEANED UP AND DOES NOT EFF ECT VENTILLATION OR TRAVELWAYS. ALL ACCESS TO FALL AREA HAS BEEN CRIBBEB AND DANGERED OFF.