Emergency Preparedness and Major Incident Terminology

Within the emergency preparedness and major incident response environment, there is a wide range of specialist terminology used by professionals across multiple agencies. This section introduces some of the most common terms you will encounter throughout this course. While this is only a brief overview, becoming familiar with these terms will help you understand inter-agency communication and coordination during an incident.

Key Terminology and Acronyms

NISLO – National Incident Liaison Officer

A National Incident Liaison Officer (NISLO) is a security-cleared specialist who possesses detailed knowledge of the capabilities and resources of other emergency services. Their role is to advise the incident commander on what inter-agency assets may be available at the scene. The liaison aspect of their role involves coordinating and communicating with representatives from other organisations attending the incident.

HAZMAT – Hazardous Materials

HAZMAT refers to hazardous materials. A HAZMAT incident involves the accidental release or exposure to dangerous substances, such as chemicals or biological agents, which may pose a threat to human health or the environment.

CBRN – Chemical, Biological, Radiological and Nuclear

CBRN incidents are deliberate releases of chemical, biological, radiological, or nuclear materials—typically as acts of terrorism or sabotage. These events require highly specialised response teams and strict safety protocols.

HEMS – Helicopter Emergency Medical Services

HEMS stands for Helicopter Emergency Medical Services. These are usually charity-led operations that work in partnership with the ambulance service. HEMS provides rapid-response medical support and patient transport, often with assistance from the ambulance service in areas such as administration, radio communication, and coordination.

MACA – Military Aid to the Civil Authorities

MACA refers to requests for military support to assist civilian authorities. These requests are processed through a JRLO (Joint Regional Liaison Officer), who serves as the regional representative linking the civilian authority with the Ministry of Defence and the Secretary of State for Defence to authorise the use of military resources.

METHANE – Major Incident Reporting Format

METHANE is a structured communication tool used to pass critical information about an incident in a consistent format. It ensures that emergency services and agencies receive accurate, up-to-date information during an unfolding situation.

ATMIST – Clinical Handover Format

ATMIST is a concise reporting format used between healthcare professionals to transfer essential clinical details about a single patient. It allows for the rapid exchange of information, particularly in time-critical situations.

TRTS – Triage Revised Trauma Score

The Triage Revised Trauma Score (TRTS) is a system used during secondary triage to assess the severity of a casualty’s injuries. It applies numerical scores to physiological measurements such as breathing, circulation, and responsiveness to prioritise treatment and evacuation.

Subject Matter Experts (SMEs)

In a major incident, a range of Subject Matter Experts (SMEs) may be called upon. These specialists bring expertise in specific fields such as radiological, chemical, nuclear, or firearms incidents, and may come from different agencies, including emergency services, the military, or government departments.

C2, C3, C4 and C4I

These terms describe increasing levels of operational coordination:

• C2: Command and Control
• C3: Command, Control, and Communication
• C4: Command, Control, Communication, and Coordination
• C4I: Command, Control, Communication, Coordination, and Information

These terms are often used by military and specialist emergency preparedness units to describe the structure and flow of decision-making in complex operations.

JESIP – Joint Emergency Services Interoperability Principles

JESIP stands for the Joint Emergency Services Interoperability Principles. This framework provides a standardised approach to information sharing, coordination, and joint decision-making between the emergency services during a major incident. The JESIP principles aim to improve multi-agency effectiveness and ensure a consistent national response.

Summary

Understanding key terminology is essential for anyone involved in emergency planning, response, or recovery. These acronyms and phrases provide a shared language that enables multiple agencies to work efficiently and effectively under pressure. Throughout this course, you’ll see many of these terms used in context to help reinforce your understanding of how they apply in real-world incident management.