Which statement correctly distinguishes secondary from tertiary blast injuries?

• A. Secondary is caused by blast overpressure; tertiary is caused by debris
• B. Secondary is caused by debris; tertiary is caused by being thrown into objects
• C. Secondary is caused by burns; tertiary is caused by pressure
• D. Secondary and tertiary are the same

Answer: (B)

In blast injuries, the mechanisms are defined by how the injury occurs. Secondary injuries come from debris and fragments—shrapnel, wood, metal, or other material—that strike the body, causing penetrating or blunt trauma. Tertiary injuries happen when the force of the blast wind throws the person into objects or the ground, leading to injuries from impact, such as blunt trauma and fractures.

The statement that matches this distinction correctly assigns debris to secondary injuries and being thrown into objects to tertiary injuries. The other ideas mix up the mechanisms—for example, attributing secondary injuries to the blast overpressure (that describes primary injuries) or suggesting burns or that the two are the same—so they don’t fit the true separation of causes.