Corporal Barry Foust died as a result of cancer that he developed following his response to the Pentagon on the morning of September 11, 2001, and during his subsequent assignment to the search and recovery efforts after the 9/11 Terrorist Attacks.
When American Airlines Flight 77 struck the Pentagon, Corporal Foust was at the intersection of Walter Reed Drive and Columbia Pike. He worked that day to clear the roadway for first responders. Throughout the week, he returned to the Pentagon crash site to collect evidence.
Corporal Foust had served with the Arlington County Police Department for over 35 years. He had previously served with the Metropolitan Washington Airports Authority Police Department for almost 2 years. Survivors include his wife, daughter, sisters, and granddaughter.
Source: ODMP
https://www.odmp.org/officer/27809-corporal-barry-james-foust