Explosions produce sudden and violent disturbances of the air. As a result, individuals may be thrown down or injured by falling wreckage. In addition, the blast of air itself may strike the body with such force as to cause severe or fatal internal injuries. There may be blast injuries affecting more than one part of the body; any combination of injuries to the following areas may occur.

Lungs
Blast can damage the small blood vessels in the lungs, causing internal bleeding. The patient will be in shock and will have difficulty breathing, along with a feeling of tightness or pain in the chest. The face will usually appear blue, and there may be blood-stained froth in the mouth.
Move the patient into fresh air if possible. Support him in a half-sitting position. Loosen tight clothing and keep him warm. Encourage him to cough and spit out any phlegm. Morphine must not be given. If breathing stops, provide artificial respiration using the mouth-to-mouth method.

Head
Blast injuries to the head are similar to concussion. In some cases, paralysis of the limbs may occur due to damage to the spinal cord. The patient may be completely unconscious or extremely dazed. In such cases, individuals may sit motionless, unable to respond or take notice of their surroundings. Although they may appear outwardly uninjured, they lack the energy or awareness to act.
If unconscious, treat accordingly.
If dazed, guide them firmly to safety and give clear instructions. Treat them as you would very young children. This approach may save lives, especially in dangerous situations where they may otherwise fail to act.

Abdomen
Blast injuries may cause internal bleeding in the abdomen due to damage to internal organs. This is often seen in underwater explosions affecting individuals in the sea. Shock and abdominal pain are the main signs and may appear after some time.
For treatment, refer to Injury to the abdomen and Internal bleeding.