An explosion or blast is caused by a rapid expansion of gas from chemical reactions or incendiary devices. Signs of an explosion may be a very loud noise or series of noises and vibrations, fire, heat or smoke, falling glass or debris, or building damage.

Immediate actions
  • Immediately take cover under tables, desks, or other object that can give protection against falling glass or other debris.
  • After effects of the explosion have subsided, evacuate the building as quickly and calmly as possible. If there is a fire, stay low to the ground.
  • Use stairs only; do not use elevators.
  • Assist others in exiting the building, particularly any persons with access and function needs. If such persons require extra assistance, they should move to or be moved to a designated stairwell landing and wait for assistance by trained first responders.
  • If it is safe to do so, activate a fire alarm on the way out.
  • Assist others in existing the building.
  • Move to a clear area at least 500 feet away from the affected building.
  • Keep streets, fire lanes, hydrant areas, and walkways clear for emergency vehicles and crews.
  • As soon as possible and from a safe location, dial 911 to report the incident.
  • Report any injured, missing, or trapped persons to emergency personnel.
  • If you are trapped, tap on a pipe or wall, and shout out so rescuers can locate where you are.
  • Do not re-enter the building.
  • Untrained persons should not attempt to rescue people who are inside a collapsed building. Wait for emergency personnel to arrive.