sentences:  Four companies (about 500 soldiers) moved in, they were not needed after Arizona became a state in 1912, and the place was deserted except for a maintenance crew.In 1918 during World War I, the Army reactivated Fort Whipple as U.S. Army Hospital #20 for respiratory illnesses, many with tuberculosis (TB) and soldiers injured by nerve gas.It had 22 buildings and 900 sick beds.