Final answer:
During a HazMat incident, triage by an EMT is best performed in the Warm zone, as it offers a safer environment than the Hot zone and is near the patient care area, unlike the Cold zone.
Step-by-step explanation:
Different zones are established during a HazMat incident to manage the scene and ensure the safety of both the public and emergency responders. Triage is a process where patients are sorted according to the urgency of their need for medical care. For an Emergency Medical Technician (EMT) to perform triage effectively, it is best done in the Warm zone of a HazMat incident. This zone is where decontamination occurs and is just outside the immediate danger of the Hot zone, allowing for a safer environment to assess and prioritize patients before they are transported out for further medical care. It is also not too distant from the incident to ensure that critical patients can be treated promptly. The Cold zone is typically the command and support area, which is too far from the immediate patient care area for effective triage.