Blackhawk gases crowd

In May 2005 civilian security contractor Blackhawk dropped from a helicopter noxious gas on an unruly crowd at a checkpoint leading into the Green Zone in Baghdad, The New York Times reports. The helicopter's rotors drove clouds of CS, a riot-control gas, onto the soldiers guarding the checkpoint.

"This was decidedly uncool and very, very dangerous," Capt. Kincy Clark of the Army, the senior officer at the scene, wrote later that day.