The unit was formed as a direct response to the 1998 Raccoon City Destruction Incident. During the viral outbreak, the US Army and National Guard failed in their efforts to destroy the Zombies, and an entire Delta Force unit was wiped out in a fight with T-103 Tyrants. The losses confirmed the military's need for a dedicated anti-B.O.W. task force specifically trained for dealing with biohazards, as well as infiltration.