While not standard procedure , ATF agents had their blood type written on their arms or neck after leaving the staging area and before the raid .
Blood type was recommended by the military to facilitate speedy blood transfusions in the case of injury .
While not standard procedure , ATF agents had their blood type written on their arms or neck after leaving the staging area and before the raid , because it was recommended by the military to facilitate speedy blood transfusions in the case of injury .