First Aid Triage: How to Prioritise Multiple Casualties

First aid triage is the process of identifying which casualties need the most urgent attention when several people are injured or unwell. In an emergency involving multiple casualties, understanding how to recognise life-threatening conditions and prioritise assistance can make an important difference.

Imagine arriving at a workplace accident where three people have been injured. One person is shouting because of a painful arm injury, another is sitting quietly with a serious bleeding wound, and a third is lying on the ground, apparently unconscious.

Who should you help first?

The answer is not necessarily the person making the most noise. A casualty who is quiet or unresponsive may have a more serious condition requiring immediate attention.

Although formal triage systems are used by trained emergency responders, workplace first aiders can apply basic assessment and prioritisation principles to help manage an emergency safely.

This guide explains what first aid triage means, how to prioritise multiple casualties, which injuries require urgent attention and how first aid training can prepare you to respond.

What Is First Aid Triage?

First aid triage involves assessing casualties to identify the most urgent needs and deciding how available assistance should be used.

The word triage comes from the French word meaning to sort or select.

In emergency care, triage helps responders prioritise people according to the urgency of their condition rather than simply treating casualties in the order they are discovered.

When several people need help, it may not be possible to provide immediate treatment to everyone.

A first aider must therefore recognise immediate threats to life, summon additional assistance and provide appropriate care within their training.

Why Is Triage Important in First Aid?

First aid triage is particularly valuable when an incident involves more than one casualty.

Examples include:

• Road traffic collisions involving several injured people.
• Workplace accidents involving machinery or equipment.
• Falls or structural incidents affecting multiple workers.
• Fires or incidents involving smoke inhalation.
• Public events where several people become injured or unwell.
• Incidents involving hazardous substances.

In these situations, a first aider may have limited equipment, limited assistance and several casualties requiring attention.

Understanding how to recognise urgent conditions helps ensure that serious injuries are not overlooked.

However, a workplace first aider is not expected to perform the same detailed triage assessments as an ambulance clinician or specialist emergency responder.

The priority is to recognise danger, call for help and provide appropriate life-saving assistance.

First Aid Triage: The First Five Priorities

When responding to an incident involving multiple casualties, it is important to follow a structured approach.

The following five priorities provide a practical framework for workplace first aiders.

1. Check the Scene Is Safe

Before approaching any casualty, assess the surrounding area for danger.

Potential hazards may include:

• Moving vehicles or machinery.
• Electricity or damaged electrical equipment.
• Fire, smoke or hazardous substances.
• Falling objects or unstable structures.
• Broken glass or sharp materials.
• Violence or other ongoing threats.

Do not enter an unsafe environment or expose yourself to unnecessary danger.

Where possible, make the area safe without putting yourself at risk.

If the incident involves serious hazards, move to a safe location and request the appropriate emergency services.

A first aider who becomes injured cannot provide effective assistance to others.

2. Call 999 and Request Additional Help

If several casualties are injured, particularly where serious injuries are suspected, call 999 promptly.

Tell the emergency call handler:

• Your exact location.
• What has happened.
• The approximate number of casualties.
• Whether anyone is unconscious or not breathing normally.
• Whether there is life-threatening bleeding.
• Any continuing dangers at the scene.
• How emergency responders can safely access the location.

Follow the instructions provided by the call handler.

If other people are available, ask them to contact emergency services, bring first aid equipment or retrieve an automated external defibrillator (AED).

Where practical, use your phone on speaker so you can continue assisting casualties while receiving instructions.

3. Identify Immediate Life-Threatening Conditions

When several people are injured, rapidly identify anyone who may need immediate life-saving assistance.

Particular concerns include:

• Life-threatening bleeding.
• An unresponsive casualty who is not breathing normally.
• An obstructed airway.
• An unresponsive casualty whose airway or breathing requires attention.
• Severe breathing difficulties.

These conditions may deteriorate rapidly without intervention.

A casualty who is walking and talking may still have a serious injury, but someone with an immediate threat to life may require more urgent assistance.

Do not assume that the loudest casualty is the most seriously injured.

4. Provide Immediate Life-Saving First Aid

Once an immediate life threat is identified, provide appropriate treatment within your training and capabilities.

Examples include:

• Applying firm direct pressure to life-threatening bleeding.
• Using additional bleeding-control techniques where appropriate and within your training.
• Opening and maintaining an airway.
• Starting CPR when a casualty is unresponsive and not breathing normally.
• Using an AED as soon as one is available.
• Providing appropriate first aid for choking.

The treatment required depends on the casualty’s condition, the available resources and the number of people requiring assistance.

When multiple casualties need simultaneous life-saving interventions, ask other trained people to assist and follow emergency call-handler instructions.

5. Continue Monitoring and Reassessing Casualties

A casualty’s condition can change.

Someone who initially appears stable may deteriorate, while another casualty may respond to treatment.

Continue to monitor casualties as circumstances allow.

Watch for changes in:

• Responsiveness.
• Breathing.
• Bleeding.
• Skin colour.
• General condition.

Reassess priorities if someone’s condition worsens.

When emergency services arrive, explain what happened, what you observed and what treatment has already been provided.

How to Prioritise Multiple Casualties in First Aid

Prioritising multiple casualties requires a balance between urgency, available assistance and the first aider’s level of training.

The following examples demonstrate how different situations may affect priorities.

Casualty with Life-Threatening Bleeding

A casualty experiencing severe, uncontrolled bleeding requires immediate attention.

Signs may include:

• Rapid or heavy blood loss.
• Blood spurting or flowing continuously from a wound.
• Bleeding that is difficult to control.
• A traumatic amputation.
• Signs of serious deterioration associated with blood loss.

Call 999 and apply firm direct pressure immediately.

Additional bleeding-control techniques, including suitable dressings or a tourniquet, may be necessary depending on the injury and the first aider’s training.

Controlling life-threatening bleeding is particularly important because substantial blood loss can rapidly become fatal.

Casualty Who Is Unresponsive and Not Breathing Normally

An unresponsive casualty who is not breathing normally may be experiencing cardiac arrest.

Call 999, start CPR and use an AED as soon as possible.

If other people are available, direct someone to retrieve the AED and another person to assist with other casualties.

In a multiple-casualty incident, the emergency call handler can help guide your response according to the circumstances and resources available.

Casualty Who Is Unresponsive but Breathing Normally

An unresponsive casualty who is breathing normally still requires urgent assessment and monitoring.

Call 999.

Follow current first aid guidance on maintaining the airway and using the recovery position when appropriate.

Continue checking breathing because the casualty’s condition may change.

Casualty with a Suspected Fracture

A casualty with a suspected fracture may be in considerable pain and require medical assessment.

However, if another casualty has uncontrolled life-threatening bleeding, the bleeding injury will generally require more immediate intervention.

Once immediate life threats are being managed, provide appropriate care for the suspected fracture.

This may include supporting the injured area, minimising unnecessary movement and arranging medical assistance.

Casualty with Minor Injuries

A casualty with a small cut or minor injury may be able to wait briefly while more serious conditions are addressed.

Where possible, ask an uninjured person to stay with them and report any changes.

Minor injuries should not be ignored, but they should not distract from immediate life-saving priorities.

Understanding the ABCDE Approach in First Aid

The Resuscitation Council UK’s 2025 First Aid Guidelines recommend using a structured ABCDE approach to identify and manage life-threatening conditions.

ABCDE stands for:

• A – Airway: Is the airway open and clear?
• B – Breathing: Is the casualty breathing adequately?
• C – Circulation: Are there signs of serious bleeding or circulatory problems?
• D – Disability: Is there an altered level of consciousness or another neurological concern?
• E – Exposure: Are there other injuries or important findings that need identifying while protecting the casualty from unnecessary exposure and heat loss?

Scene safety, responsiveness and life-threatening bleeding also require immediate attention.

For workplace first aiders, the purpose of a structured assessment is to recognise serious problems promptly and provide suitable assistance.

It is not necessary to perform complex clinical examinations or assessments beyond your training.

The full guidance is available from the Resuscitation Council UK First Aid Guidelines.

What Is the Difference Between First Aid Triage and Emergency-Service Triage?

There is an important difference between the basic prioritisation used by workplace first aiders and formal triage systems used during major incidents.

Basic First Aid Prioritisation

A workplace first aider should focus on:

• Identifying immediate danger.
• Calling emergency services.
• Recognising life-threatening conditions.
• Providing appropriate first aid.
• Requesting assistance from others.
• Monitoring casualties.
• Passing information to emergency responders.

These actions help first aiders manage incidents safely without exceeding their competence.

Formal Emergency-Service Triage

Emergency services may use established triage systems when responding to incidents involving large numbers of casualties.

These systems help responders rapidly identify treatment priorities and allocate available resources.

In England, NHS major incident arrangements include the Major Incident Triage Tool (MITT) and Ten Second Triage (TST).

Formal triage may involve priority categories, clinical assessment tools and casualty labelling.

These systems should be used by responders who have received the appropriate training and are operating under relevant procedures.

Completing a standard EFAW or FAW qualification does not automatically qualify someone to carry out formal major incident triage.

For further information, see the NHS England guidance on major incident triage.

First Aid Triage in a Workplace Emergency: Practical Example

Consider a manufacturing workplace where an accident involving machinery results in three casualties.

Casualty A: A worker has a painful wrist injury and is shouting for help.

Casualty B: Another worker has a deep leg wound with heavy bleeding.

Casualty C: A third worker is lying on the floor and appears unresponsive.

What should the workplace first aider do?

Step 1: Assess the Danger

Ensure that the machinery is stopped and the area is safe before approaching.

Do not enter an area where machinery, electricity or other hazards remain uncontrolled.

Step 2: Call for Emergency Assistance

Call 999 and explain that there are three casualties, including one who is unresponsive and another with serious bleeding.

Ask colleagues to bring the first aid kit and AED.

Step 3: Identify Immediate Threats

The worker with heavy bleeding needs immediate bleeding control.

The unresponsive worker requires an immediate assessment of responsiveness and breathing.

The worker with the wrist injury also needs assistance, but may be able to wait briefly while immediate life threats are addressed.

Step 4: Use Available Assistance

If other trained first aiders are present, allocate tasks according to their competence.

One person may control severe bleeding while another assesses the unresponsive casualty and starts CPR if required.

If you are the only first aider, follow the emergency call handler’s guidance and use available bystanders to help with safe, straightforward tasks.

Step 5: Monitor and Handover

Continue providing appropriate first aid and monitoring casualties until emergency responders take over.

Tell the ambulance crew what happened, what you found and what treatment was provided.

This example demonstrates why preparation, communication and practical training are so important.

There is no single fixed treatment order that will be correct in every multiple-casualty emergency. Decisions depend on the conditions, available resources and instructions from emergency services.

Common Mistakes When Prioritising Casualties

Multiple-casualty emergencies can be stressful, particularly when people are shouting or several injuries are visible.

Some common mistakes include:

Helping the Loudest Casualty First

A casualty who is shouting may attract attention, but another person who is quiet or unresponsive may be more seriously injured.

Always consider the urgency of each casualty’s condition.

Failing to Check for Danger

Rushing towards casualties without assessing the scene can expose the first aider and others to additional injuries.

Scene safety must remain a priority.

Delaying the Emergency Call

Do not wait until every casualty has been assessed before requesting emergency assistance when a serious incident is apparent.

Calling 999 early allows professional help to be dispatched while first aid is being provided.

Focusing on Minor Injuries

Treating a minor cut or suspected sprain while another casualty has life-threatening bleeding can delay essential treatment.

Immediate threats to life require priority attention.

Trying to Manage Everything Alone

Where other people are available, ask for assistance.

Simple tasks such as calling 999, retrieving equipment or directing emergency vehicles can make a significant difference.

Failing to Reassess Casualties

A casualty’s condition may deteriorate after the initial assessment.

Continue monitoring casualties and reassess priorities when necessary.

Why First Aid Triage Skills Matter for Businesses

Workplaces should consider the types of emergencies that could reasonably occur when completing their first aid needs assessment.

Some environments present greater potential for incidents involving multiple casualties.

Examples include:

• Manufacturing and engineering workplaces.
• Construction sites.
• Warehouses and logistics operations.
• Agricultural and forestry settings.
• Large public events.
• Schools and childcare environments.
• Workplaces involving hazardous machinery or substances.

The appropriate first aid arrangements depend on the nature of the hazards, workforce size, location and other relevant circumstances.

Businesses should also consider whether additional emergency procedures, equipment or specialist training are required.

The Health and Safety Executive’s first aid at work guidance explains how employers should assess and provide suitable first aid arrangements.

Does EFAW or FAW Training Cover First Aid Triage?

Emergency First Aid at Work (EFAW) and First Aid at Work (FAW) courses teach essential emergency assessment and response skills.

These include recognising life-threatening conditions, summoning assistance and providing appropriate first aid.

Although standard workplace first aid qualifications are not specialist major incident triage courses, the practical skills they develop are relevant when responding to incidents involving multiple casualties.

Emergency First Aid at Work (EFAW)

Our Emergency First Aid at Work course provides essential practical skills for workplace first aiders.

Learners develop the knowledge and confidence to respond to emergencies, including cardiac arrest, choking, bleeding and other urgent conditions.

First Aid at Work (FAW)

Our First Aid at Work course provides more extensive training across a wider range of injuries and medical emergencies.

It is suitable for workplaces where the first aid needs assessment identifies a requirement for broader training.

Onsite First Aid Training for Businesses

For businesses with several employees requiring training, onsite courses provide an opportunity to develop practical first aid skills in a familiar workplace setting.

Where appropriate, training discussions can consider the hazards and emergency scenarios relevant to your organisation.

First Aid and Safety Training is a Qualsafe Awards Approved Training Centre delivering regulated qualifications awarded by Qualsafe Awards, an Ofqual-recognised awarding organisation.

Frequently Asked Questions About First Aid Triage

What Does Triage Mean in First Aid?

Triage means assessing and prioritising casualties according to the urgency of their condition.

In basic first aid, this involves recognising immediate life threats and providing appropriate assistance while waiting for emergency services.

Who Should Be Treated First When There Are Multiple Casualties?

The priority is to identify and address immediate threats to life, including life-threatening bleeding, airway problems and cardiac arrest.

The order of treatment depends on the situation, available assistance and instructions from emergency services.

Can a Workplace First Aider Perform Triage?

Workplace first aiders can use basic assessment and prioritisation principles to recognise casualties needing urgent attention.

However, formal major incident triage systems require appropriate training and procedures.

Is First Aid Triage Included in EFAW Training?

EFAW teaches emergency assessment, recognising life-threatening conditions and providing immediate first aid.

It should not be described as a specialist major incident triage qualification.

What Is the Most Important First Step in a Multiple-Casualty Incident?

Check that the scene is safe and call for appropriate emergency assistance as early as possible.

Do not put yourself at risk while attempting to help others.

Why Is Severe Bleeding a Priority During Triage?

Life-threatening bleeding can cause rapid deterioration and death if it is not controlled.

Prompt bleeding control is therefore an important priority when assessing casualties.

Should You Move Casualties During Triage?

Avoid unnecessary movement, particularly where serious injuries are suspected.

However, movement may be necessary to escape immediate danger or provide essential life-saving care.

Follow your training and emergency call-handler instructions.

Develop Your Emergency First Aid Skills with FAST

Understanding first aid triage helps you recognise which casualties may need the most urgent assistance when several people are injured or unwell.

However, knowing the principles is only part of being prepared.

Practical first aid training helps you develop the confidence to assess emergencies, recognise life-threatening conditions and provide appropriate assistance while waiting for professional help.

At First Aid and Safety Training, we provide practical workplace first aid qualifications for individuals and businesses across the North East.

Our courses include Emergency First Aid at Work, First Aid at Work and Paediatric First Aid, with open courses and onsite training available.

Whether you are arranging training for a new workplace first aider or reviewing your organisation’s existing arrangements, we can help you identify a suitable course.

Real Skills, Real Confidence.

Contact First Aid and Safety Training to discuss your first aid training requirements.