Columns, Major Incidents, Mass Casualty Incidents

Planning, Training & Asking Questions Can Help EMS Prepare for MCIs

Issue 9 and Volume 42.

The day has been fairly quiet. No calls so far. Jacob, the new EMT on shift starts with some questions: “How many times a day does the train go through town, and what does it carry? It doesn’t stop for passengers—at least not in this town. Does silo dust really explode?”

Rick, the senior EMT, looks at Jacob and asks, “Where did these questions come from?” The new EMT looks back at his seasoned partner and explains he was just thinking about potentials for mass disasters in their district.

Rick responds by saying that there hasn’t been a disaster in town since he started 25 years ago. “It’s a quiet little town with not much going on. No one would want to set off a bomb here,” he explains to Jacob. “There’s no subway system, the largest venue for people to gather is the high school football field and everything in town closes by 9:00 p.m. It’s doubtful there will be a mass casualty event here.”

Asking Questions

Rick is correct that the likelihood of a large disaster occurring is low, but Jacob is also correct in his questioning about the “what ifs.”

A mass casualty incident (MCI) is defined as an event that overwhelms the local healthcare system, where the number of casualties vastly exceeds the local resources and capabilities in a short period of time.1 Given this definition, the smaller the EMS system, the less of an event it takes to create a MCI.

In a large city with multiple transporting ambulances and multiple hospitals, it may take an event of dozens or more injured people to completely overwhelm local EMS and EDs.

In many small communities, however, there may only be one or two transporting ambulances that will all transport to one local ED. In a small system, an event involving as few as 10 people could completely overwhelm EMS and ED.

With this in mind, EMS systems should regularly practice MCI scenarios. Everyone potentially involved in an MCI should participate in these simulated events. This includes the fire department (if separate from EMS), ED, law enforcement (city, county and state), neighboring departments, receiving Level 1 facilities and air medical transport services.

Other agencies to consider are local power companies, school districts and public transportation systems.

Planning Considerations

Keep the training scenarios realistic. Start by looking at your community and consider the possible areas and causes of a MCI.

Jacob asked some good questions of his partner. If trains travel through your service district, do you know their schedule? There are some communities where the train comes through at the same time people are heading to work and school. What does the train carry?

If a train carrying a toxic substance derails in the middle of the night, how many people in your community may be affected by the fumes before you can evacuate the area? A passenger train derailing will create a MCI in all communities large or small.

What about exploding silos? Compressed dust particles and ignition sources can be very volatile. Explosions create primary, secondary and tertiary mechanisms. Anyone in moderately close proximity of an exploding silo could be injured.

And sadly, rogue gunmen don’t limit their attacks to just large cities and schools. Small communities have experienced attacks at schools, shopping malls and churches.

Take a “what if” scenario from your community and build a virtual event to manage. Determine who needs to be contacted immediately and create a contact list for your dispatch center.

Don’t forget that hospitals need to know about an MCI as soon as possible to allow them time to initiate their own internal MCI plans.

Where will the command center and triage area be located? It’s happened with some incidents of mass shootings in populated areas that there’s no single site of triage. As people are injured, they flee the scene and call EMS from multiple locations around the city, making it impossible to create one central area for triage.

It may also happen that injured people head directly to the hospital, causing it to become congested before EMS even begins transporting patients.

Who does your service call for back up? Are there mutual aid agreements in place? If you call for assistance from a surrounding community, how does that affect their ability to cover their own community? Are there flight services available to respond, and if so, where can you land them and who will land them?

Plan for after the disaster as well. There may be physical rebuilding and clean-up, but it’s also important to take care of the emergency service workers. The emotional effects of an MCI, especially in a small community, can have long-lasting effects.


It’s not fun to consider the thought of a mass casualty event occurring in your city. It’s important for EMS and other emergency service workers to be prepared for an MCI in your community. Plan, practice and involve all potential responders. If an MCI does occur, be safe and remember the plans you have in place and the training you experienced. Finally, take care of each other during the event and, perhaps more importantly, after the event.


1. Ben-Ishay O, Mitaritonno M, Catena F, et al. Mass casualty incidents: Time to engage. World J Emerg Surg. 2016;11:8.