The NHS in Staffordshire is the first in UK to run an emergency drill involving new, hi-tech dummies that can mimic a range of health problems, including some life-threatening conditions.
SimMan 3G simulation mannequins, which can 'talk', blink and breathe, will be used during the mock evacuation which is happening this morning.
They exhibit vital signs such as breathing, blood pressure and a pulse which will be programmed into a computer.
The training day is being called "ExercisePrometheus" and will test the workers' response to fire evacuation.
It is taking place at Queen’s Hospital in Burton.
A number of wards will be transformed into a community health unit, mental health unit and an Emergency Admissions Unit.
Staffordshire Fire and Rescue will also be there to create harmless smoke and to make the scenario feel more real.
Medical, nursing and clerical staff will be playing the parts of other patients or be responsible for evacuating the smoke-logged wards as if on a real shift.