When should security isolation of the incident scene start?

A.
As soon as the disaster plan is implemented

B.
Immediately after the emergency is discovered

C.
After all personnel have been evacuated

D.
When hazardous materials have been discovered at the site

Explanation:
Isolation of the incident scene should begin as soon as the
emergency has been discovered. Authorized personnel should attempt
to secure the scene and control access; however, no one should be
placed in physical danger to perform these functions. Its important for
life safety that access be controlled immediately at the scene, and only
by trained personnel directly involved in the disaster response.
Additional injury or exposure to recovery personnel after the initial
incident must be tightly controlled. Source: Emergency Management
Guide for Business and Industry, Federal Emergency Management
Agency, August, 1998.