When something goes wrong on site, people fall back on whatever was arranged beforehand. An emergency plan sets that out for each building and shift: how the alarm is raised, who takes charge, where people assemble, how the headcount reaches the person in control, and who meets the emergency services.
This programme trains the people who will write and run that plan. It treats the plan as something to be tested, because a plan that has never been tested is only a hypothesis, and reviewed after every drill or incident.