Section 1: Introduction to CBRNE Concepts

In this section, we will define CBRNE and several related terms to lay the foundation for the rest of the course. We will also consider differences between hazardous materials (hazmat) incidents and CBRNE incidents, and review some health-related issues associated with CBRNE incidents.

Five scenes: Chemical (two workers in hazmat suits look onto a chemical container outdoors, with another in front of them); Biological (microscopic view of virus or bacteria); Radiological (three miscellaneous containers sit on a shelf, all with radiation warning symbols on them); Nuclear (smokestack at a nuclear plant); and Explosive (fire and smoke plume)

CBRNE: What is it?

When chemical, biological, radiological, nuclear, and explosive devices or agents are used to cause mass disruption and possibly mass casualties, they are referred to as CBRNE incidents.

CBRNE incidents are most associated with terrorism, and CBRNE agents or devices are often referred to as weapons of mass destruction, or WMD. However, this is not entirely accurate. Although CBRNE agents often cause mass destruction—and certainly many have the potential to do so—this is not necessarily the case. Use of CBRNE agents by terrorists may actually cause a limited number of casualties, but have a large terrorizing effect and lead to disruption of society.

For example, in 2001, after the devastation of the World Trade Center, letters containing anthrax spores were sent to various media outlets and politicians. Although there were only five deaths and 22 others sickened by the anthrax, the nation was terrorized. Office workers were afraid to open mail, reports of white powder were investigated regularly, and mail delivery was disrupted. The fear and psychological damage were disproportionate to the number of deaths or injuries.

Warning, Detection, and Magnitude

As illustrated in Table 1, there is a wide variation in CBRNE types based on the time of the incident, the magnitude of the impact, and the availability of the agent or device. Some are silent killers, some have a very small likelihood of occurrence, and some are widely available.

Incident Warning / time to injury or illness Magnitude Availability
Chemicals Seconds to hours Localized to regional High
Biologicals Days to weeks Local to global Medium
Radiologicals Hours to days Local Medium
Nuclear Minutes to hours City to regional Very low
Explosives Immediate Local Medium/high

Table 1: Warning, magnitude, and availability of materials for CBRNE incidents

For example, in general, chemicals are easily available, and can take seconds to hours for injury or illness after exposure. The impacts tend to be localized. The likelihood of occurrence is high and with lower disruption to society. Contrast this to a nuclear incident, which would have immediate- to long-term impact, depending on the location. The magnitude can be large and the potential for social and economic disruption huge, but the chance of occurrence is extremely low.


It is important to understand the differences between terms used when working with disasters, hazardous incidents, and CBRNE activities. Select each term below to learn more about it.

Hazardous Materials, or Hazmat, are substances that, if not properly controlled, pose a risk to people, property or the environment. Hazmat incidents are likely to be accidents, not deliberate acts of terrorism. Hazmat incidents are generally contained and thus do not become mass casualty events or disasters.

Hazard is a circumstance or condition that can cause harm. Examples include:

  • Chemical plant near water supply
  • Bioterrorism agents
  • Nuclear plants and radiological devices
  • Earthquake fault line
  • Coastal hurricane zone

What hazards or vulnerabilities can you identify in your own community?

An incident or event is the actualization of a hazard that may cause damage. Examples include:

  • Chemical leak into water supply
  • Earthquake
  • Dirty bomb
  • Anthrax release

Types of incidents/events:

  • Accidental (Hazmat)—human error or natural/technological reasons, such as:
    • Chemical spills/leaks
    • Transportation accidents
    • Fertilizer plant explosions
    • Outbreaks of infectious diseases (unless deliberately infected)
  • Deliberate (CBRNE)—intention, criminal acts, such as:
    • Chemical and biological warfare
    • Chemical releases or dumping
    • Politically motivated poisoning
    • Terrorist attacks

A "natural or manmade event that results in an imbalance between the supply and demand for existing resources." Examples include:

  • Chemical contamination of vast water supply
  • Terrorist explosion of dirty bomb
  • Chemical or biological warfare

An incident or event becomes a disaster when the local response capacity is insufficient and external assistance is required. In a disaster, basic services of society become disrupted and losses exceed the local capacity to respond. In other words, there is a massive disruptive impact. All disasters can be thought of as local, until they are not.

Hazards themselves are not disasters, but rather are factors that cause disasters. It is the impact on people (medical and psychological), infrastructure, and environment that combine to result in a disaster.

Source: Noji E. (ed.) The public health consequences of disasters.

Are Hazmat Incidents CBRNE Incidents?

A CBRNE incident differs from a hazardous material incident in both effect scope and intent. CBRNE incidents are responded to under the assumption that they are deliberate, malicious acts with the intention to kill, sicken, and disrupt society. A hazardous material (hazmat) incident is likely accidental. Evidence preservation and perpetrator apprehension are of greater concern with CBRNE incidents than with hazmat incidents.

Yet, a hazmat incident can also be a disaster incident. Consider this example: an industrial chemical disaster is defined as the release or spill of a toxic chemical that results in an abrupt and serious disruption of the functioning of society. This leads to widespread human, material, or environmental losses that exceed the ability of the affected society to cope using its own resources alone. However, these are rare. Most hazmat incidents are smaller scale.

Most of the information tools that are presented in this training do not differentiate between hazmat and CBRNE. They can be used for both types.

Table 2 compares the effect scope, intent, and nature of CBRNE and hazmat incidents.

Characteristic CBRNE Incident Hazmat Incident
Effect scope Small to large scale, potentially mass casualty Usually small scale (rarely a widespread disaster)
Intent Deliberate, malicious acts with intention to kill, sicken, and/or disrupt society Likely accidental
Nature Chemical, biological, radiological, nuclear, and/or explosive Usually chemical, but can be biological and radiological

Table 2: Comparison of the effect scope, intent, and nature of CBRNE and hazmat incidents

Disaster Cycle

Typically, disasters are discussed in four phases.


  • Uses information to prevent devastation
  • Build resilience to disasters
  • Lessen impact
  • Shorten recovery


  • Most critical phase from an information perspective
  • Response plans are written
  • Training exercises take place
  • Information gaps are identified and addressed


  • Usually the longest phase
  • Normal may never be achieved or may take years
  • Psychological effects become prevalent


  • Saving lives, property, environment
  • Preserving evidence (CBRNE)
  • Information must be readily available at this point

CBRNE Disasters

Are all CBRNE incidents disasters? No, not all are disasters. As stated earlier, an incident becomes a disaster when the local capacity to respond is exceeded. When a CBRNE incident has mass casualties, it becomes a disaster. A mass casualty incident is defined as large numbers of dead and injured that stress the capacity of the responders and the health care system. Therefore, all mass casualty incidents are disasters.

Remember the example of the anthrax attacks in 2001. This was a deliberate biological attack intended to generate mass fear and disruption, thus it was a CBRNE incident. However, the low number of dead and injured means it was not a mass casualty incident.

CBRNE Health-Related Issues to Consider

When thinking about CBRNE incidents, there are a number of health-related issues to consider. In addition to injuries one would expect to find, there are other issues to be prepared for, many of which stem more from the fear and disruption to society caused by the incident than from mass casualties. These issues include:

  • Identification and treatment
  • Mass decontamination
  • Medical surge
  • Medical countermeasures
  • Mass dispensing (PODs)
  • Mass fatalities
  • Mass gatherings
  • Population movements
  • Family reunification
  • Psychological issues

Common Considerations for CBRNE Threats

After any type of CBRNE incident, the major areas of concern are as follows. Click the left and right arrows to learn more.

Routes of Exposure to Chemical, Biological, and Radiological Agents

There are three basic ways a person can be exposed to these types of agents:


Animated illustration of unknown substances, represented by skull and crossbone symbols, entering into the mouth and nose and depositing into the lungs.

The agent is breathed into the respiratory tract.


Animated illustration of unknown substances, represented by skull and crossbone symbols, entering into the mouth and depositing into the digestive tract.

The agent is taken into the body via contaminated drinks or food.

Dermal (skin)

Animated illustration of unknown substances, represented by skull and crossbone symbols, landing onto and being absorbed into the skin of the arms and legs.

The agent is absorbed through the skin, sometimes even through layers of clothing.

Exposure can occur as a combination of the different routes.

Knowledge Check

After Hurricane Harvey hit Texas in August 2017, flooding disabled the refrigeration systems at the Arkema Inc. chemical plant in Crosby, TX, which manufactures organic peroxides. With personnel evacuated and lack of refrigeration, the peroxides exploded and fires ensued (learn more).

True or False: The Arkema Inc. Chemical Plant Fire was a CBRNE incident.

Key Points

In this section, we covered the following main points:

  • CBRNE refers to chemical, biological, radiological, nuclear, and explosive incidents.
  • CBRNE incidents are assumed to be deliberate; Hazmat incidents are likely accidental.
  • The disaster cycle consists of:
    • Preparedness (the most critical phase)—response plans are written, training exercises are performed, and information gaps are identified and addressed
    • Response—focus on saving lives, property, and the environment, and on preserving evidence in a CBRNE incident
    • Recovery (the longest phase)—focus on returning to normalcy or as close to normal as possible; psychological effects often become prevalent in this phase
    • Mitigation—use of information to prevent devastation, build resilience to disasters, and shorten the recovery
  • Major areas of concern for any type of CBRNE incident include:
    • Scale of the incident
    • Responder protection
    • Affected population
    • Affected animals
    • Environment
    • Preservation of forensic evidence
  • Exposure to an agent can occur through:
    • Inhalation
    • Ingestion
    • Dermal (skin) absorption