Effects on living things To people who are close to a blast incident, such as bomb disposal technicians, soldiers wearing body armor, deminers, or individuals wearing little to no protection, there are four types of blast effects on the human body: overpressure (shock), fragmentation, impact, and heat. Overpressure refers to the sudden and drastic rise in ambient pressure that can damage the internal organs, possibly leading to permanent damage or death. Fragmentation can also include sand, debris and vegetation from the area surrounding the blast source. This is very common in anti-personnel mine blasts. The projection of materials poses a potentially lethal threat caused by cuts in soft tissues, as well as infections, and injuries to the internal organs. When the overpressure wave impacts the body it can induce violent levels of blast-induced acceleration. Resulting injuries may range from minor to unsurvivable. Immediately following this initial acceleration, deceleration injuries can occur when a person impacts directly against a rigid surface or obstacle after being set in motion by the force of the blast. Finally, injury and fatality can result from the explosive fireball as well as incendiary agents projected onto the body. Personal protective equipment, such as a bomb suit or demining ensemble, as well as helmets, visors and foot protection, can dramatically reduce the four effects, depending upon the charge, proximity and other variables. Types Experts commonly distinguish between civilian and military bombs. The latter are almost always mass-produced weapons, developed and constructed to a standard design out of standard components and intended to be deployed in a standard explosive device. IEDs are divided into three basic categories by basic size and delivery. Type 76, IEDs are hand-carried parcel or suitcase bombs, type 80, are "suicide vests" worn by a bomber, and type 3 devices are vehicles laden with explosives to act as large-scale stationary or self-propelled bombs, also known as VBIED (vehicle-borne IEDs). Improvised explosive materials are typically unstable and subject to spontaneous, unintentional detonation triggered by a wide range of environmental effects, ranging from impact and friction to electrostatic shock. Even subtle motion, change in temperature, or the nearby use of cellphones or radios can trigger an unstable or remote-controlled device. Any interaction with explosive materials or devices by unqualified personnel should be considered a grave and immediate risk of death or dire injury. The safest response to finding an object believed to be an explosive device