What must an investigator wear while conducting an investigation?

When conducting an investigation, particularly in the context of potential hazards such as fire or toxic environments, the use of an Oxygen Breathing Apparatus (OBA) is essential. An OBA provides the necessary respiratory protection against smoke, chemicals, and other harmful particulates that may be present during the investigation. This equipment ensures that the investigator can work in an environment where the air quality may be compromised, thereby allowing for a safe assessment of the situation without the immediate risk of asphyxiation or inhalation of toxic substances.

In situations where visibility may be reduced due to smoke or where there might be a risk of oxygen deficiency, the capability of the OBA becomes critical. This is especially true in maritime environments, where the potential for chemical spills or the aftermath of a fire can create hazardous conditions.

The other options, such as a standard uniform, fire-resistant suit, or protective gloves, may provide some level of protection but do not address the need for breathable air in dangerous scenarios. Therefore, the most critical piece of safety equipment for an investigator in such contexts is the Oxygen Breathing Apparatus.