No. In that situation, you should evacuate, not shelter in place.

What you should do instead

When you hear an explosion on a large plant floor followed by smoke , debris, and the fire alarm:

  • Leave the area immediately using the nearest safe exit.
  • Do not use elevators; use stairs and marked exit routes.
  • Help others evacuate if you can do so safely.
  • Once outside, move to the designated assembly point or a safe distance away from the building and stay there until instructed otherwise.
  • Report any injuries, trapped coworkers, or hazards to emergency responders.

Why you do not shelter in place here

Shelter-in-place is generally used for:

  • Chemical releases in the community (e.g., toxic gas outside).
  • Situations where the danger is outside and the inside air can be sealed off.

In your scenario:

  • The danger (explosion, fire, smoke, falling debris) is inside the building.
  • Fire alarms and visible smoke are classic triggers for evacuation, not for staying put, unless you are physically unable to evacuate safely.

So for the quiz-style question:

“You are working on a large plant floor when you hear an explosion, which is followed by billowing smoke, debris and the fire alarm going off. Should you shelter in place?”

The correct answer is: No – you should evacuate the plant following emergency exit routes.

Information gathered from public forums or data available on the internet and portrayed here.