In the basic emergency plan, which of the following steps must be included in a shutdown procedure ? Shutting off power to machines and fans Opening windows (except in case of bomb threats) Closing valves Unplugging vents and pipes Select the correct answer using the code given below :

- Shutting off power (1) and closing valves (3) are standard safety procedures in many emergency shutdowns to prevent escalation of the incident or injury. - Opening windows (2) might be done in specific emergencies (like gas leaks) but is not a universal step in a basic shutdown, especially if security or containment is an issue (as noted in the option itself regarding bomb threats). - Unplugging vents and pipes (4) is generally not part of a basic shutdown procedure and could potentially create new hazards or interfere with containment systems. Shutdown procedures focus on isolation and securing systems, not disconnecting them in a manner that might release contents or disrupt safety features.