The U.S. Army conducts a mass casualty exercise at Fort Sam Houston, Texas, which simulates an aerial collision near San Antonio on Oct. 21. About 55 people with simulated injuries were taken to Brock Army Medical Center as casualties to review admission, triage, emergency care, patient monitoring and coordination between hospital departments. 50 regional medical centers participated. The exercise is designed to identify deficiencies and improve preparedness for incidents with extensive casualties.