When Chevron fire department personnel took control of the leak response, the fire fighters created and taped off a 20 foot by 20 foot “hot zone” around the leak location. Chevron defines a hot zone as “the immediate release area [emphasis in the original] of the incident where there is risk of exposure or injuries due to flame contact, radiant heat, or hazardous materials.” The size and location of the hot zone is determined by the Incident Commander.