In a disaster, natural or man-made, involving a blast or explosion and resulting in mass casualties, many serious or fatal injuries are caused by driven projectiles (also called driving injuries). Quite often, driving injuries are caused by shards of flying glass . The latter part of the twentieth century and the beginning of the twenty-first centuries documented significant increases in the number of terrorist activities resulting in massive serious injuries and loss of life. In the United States, the most notable terrorist activities resulting in driving injuries (among the myriad of other severe and lethal outcomes) occurring during that time period were attacks on abortion clinics, the Atlanta Olympic Park and associated area bombings, the bombing of the Murrah Federal Building in Oklahoma City, and the two attacks on New York's World Trade Towers, with the final attack on September 11, 2001, resulting in the collapse of the buildings. Explosive devices are commonly used both during times of war and in acts of terrorism worldwide. On a lesser scale, driving injuries may also be caused by industrial accidents, fireworks explosions, and motor vehicle accidents.
In the event of a blast, physicians and forensic examiners identify injuries of four types that occur: primary, secondary, tertiary, and quaternary or miscellaneous. Primary injuries are caused by the intense wave of excess pressure emitted immediately after a blast; this generally affects air-filled regions of the body, such as the tympanic membranes (ear drums and middle ear), gastrointestinal tract, and lungs. Secondary injuries are caused by driven objects; debris and shards of glass become high-speed projectiles that are driven into any part of the body. Driving injuries can result in blunt trauma (severe surface and underlying tissue injury that does not result in ruptured skin) or penetrating ballistic fragmentation injuries (shrapnel-like pieces of shattered glass or other blast debris make high-velocity impact with the body and lacerate it, causing surface and underlying tissue damage). A significant number, estimated at around 10% of blast survivors experience driving injuries to the eye. Tertiary damage is caused when humans become projectiles as a result of the concussive effect of a blast (the very strong wind caused by a high pressure explosive), and are injured or killed when they come into contact with other objects, including other humans. Miscellaneous or quaternary injuries are all other blast or explosion-related injuries or complications.
Driving injuries are the most frequent post-explosive occurrences. Blasts in buildings or motor vehicles typically shatter windows, creating driven glass, military explosives are generally designed to fragment and create shrapnel, and terrorist bombs often contain small metal objects such as screws, nails, and glass fragments that are designed to maximize secondary blast injuries.
see also Bioterrorism; Blunt injuries, signs of; Explosives; Oklahoma bombing (1995 bombing of Alfred P. Murrah building); World Trade Center, 1993 terrorist attack.