The bombing of the Alfred P. Murrah Federal Building in Oklahoma City on April 19, 1995, was, at the time, the worst act of terrorism on American soil. The explosion killed 168 people, including twenty-one children, yet the toll extended far beyond those who were killed. Hundreds of people were injured in the blast—people who were working in the building, visiting one of the many federal offices in the building, or making a routine delivery on what had been a normal day. For those who were injured, the families of the victims who were killed, their rescuers and emergency medical personnel, and for many residents of Oklahoma City, their lives would never be the same again.

Guilt was a common feeling among both those who survived the blast and those who lost a friend or family member in the explosion. Parents felt guilty for bringing their...