In October 2017 an outbreak of E. coli O157:H7 and E. coli O26 occurred among recruits at the Marine Corps Recruit Depot in San Diego and the command's field training facilities at Edson Range, Camp Pendleton, California. Investigators identified 62 confirmed, 62 probable and 120 suspected case-patients. Thirty people were hospitalized and 15 had HUS. Poor hygiene practices among recruits and inconsistent cooking temperatures within dining facilities were noted. Consumption of undercooked beef was found to be significantly associated with illness (mOR 2.40, CI 1:04-5.72, p=0.04).