Whether at the site or in an EOC, a clear coordination and command structure is a key element in effective and efficient incident management. Managing an incident response requires coordination and command at multiple levels: at the site, in an EOC and through multi-organization coordination.

Incident management at the site begins as responders arrive at the location(s) of the incident. The first arriving responder immediately assumes the role of incident commander. If a more experienced or appropriate incident responder arrives to the location, there may be a transfer of command.

A transfer of command is the official hand over of command. The hand over process can either be verbal or written. Transfer of command is optional and depends on the needs of the incident and the response organization(s) involved. In some communities and organizations, site incident commanders are chosen ahead of time and may be pre-assigned to an incident.

EOCs often have a formal incident management structure with pre-determined EOC directors on-call to coordinate and command an incident or a departmental EOC. In the early stages of an incident response, the first arriving responder to report to an EOC may act as the EOC director. An EOC director may also begin to coordinate virtually until they are able to deploy to the EOC.

Larger or more complex incidents may have incident commanders at multiple sites. A non-site-specific incident such as flooding may require a collaborative approach between communities and organizations. Incident response efforts that involve a complex system of organizations with their own site (such as those within the health care system) are sometimes known as networked response efforts. They may operate in a more collaborative coordination and command structure known as unified command (also known as unified coordination). In order for this structure to work, multi-organization coordination is required.

4.1 Site management

Site management often involves coordinating multiple on-site incident response organizations. Effective and efficient site management enables all incident responders to work together to achieve common objectives.

The incident commander (also referred to as the incident manager) manages the incident response and the incident management team (see Section 6.1 – Site coordination and command for more information).

The primary responsibilities of the incident commander include:

  • defining the objectives, strategies and tactics for the overall incident response
  • coordinating the activities of the incident response organizations
    • for example, a serious motor vehicle accident may require the coordination of police, paramedics, fire and transportation services
  • maintaining the safety of all incident responders
  • coordinating all aspects of the site including facilities, communications, logistics and other aspects as appropriate

The incident commander coordinates and commands all of the incident site response activities. It is important to note that no organization has tactical command authority over any other organizations’ personnel or assets unless such authority is transferred. In a search and rescue operation, incident response organizations such as paramedics and emergency social services personnel may take part in the search efforts however, the police service conducting the search and rescue would have tactical command authority as the lead response organization.

Coordination and command of an incident at the site takes place from an incident command post. For more information about the incident command post and other IMS related facilities, see Appendix B – IMS facilities.

4.2 EOC management

Coordination and command activities vary between the site and the EOC. The main purpose of most EOCs is to coordinate efforts that provide support to the site.

The EOC director manages an EOC. In most incidents, the main task of an EOC director is to coordinate resources and information.

Site support from an EOC

Support to the site is different from coordination and command of the incident itself. An EOC director providing support to the site of a high-rise fire does not provide tactical decisions for fire suppression. However, if there is a request for additional firefighters and resources, the EOC director may coordinate the necessary arrangements to fulfill the request to support the site.

An EOC director may have a larger coordinating role depending on the nature and extent of an incident. For example, if the high-rise fire example mentioned earlier requires street closures in surrounding areas, the EOC director may manage a citywide transportation strategy to address traffic control issues as a result of the incident.

Coordination from an EOC

Complex incidents may consist of multiple sites or may not have a clearly defined site. In either case, it may be more effective and efficient to coordinate incident response activities from an EOC.

In complex incidents, a critical task of an EOC is coordinating and sharing incident information and situational awareness. Not all incident response organizations will be located in an EOC therefore, situational awareness will need to be shared virtually as well as through planning cycle meetings. The EOC fosters collaboration between response organizations for incidents that involve multiple sites and/or incident commanders or require a coordinated network approach.

EOCs operating under unified command play a vital role in effective and efficient response by maintaining a regular communication cycle with all incident response organizations. For more information, see Section 4.7 – Unified command (also known as unified coordination). For example, during wildfire evacuations, the Provincial Emergency Operations Centre (PEOC) maintains a regular communication cycle with host and evacuated communities, federal partners, provincial ministries, health agencies and NGOs.

Command from an EOC

When incident response activities are coordinated from an EOC, the EOC director will set the objectives, strategies and tactics for the incident. For example, a municipal EOC may coordinate local flood response efforts during spring floods.

Command during a non-site-specific incident such as a nuclear incident may take place in an EOC. Command from an EOC may also occur when the incident covers a large geographic area, such as an extreme weather event.

4.3 Additional incident management locations

Important aspects of an incident response effort such as the care and shelter of evacuated individuals may be coordinated out of additional incident management locations. These locations may include:

  • hospitals
  • reception centres
  • family and friends assistance centres (FFACs)
  • psychosocial counselling centres
  • evacuation shelters

These locations must be interoperable with the site(s) and EOC(s) and the use of IMS is recommended. A site or an EOC incident management structure may be used to organize any additional incident management locations.

Coordination with the site(s), EOC(s) and additional incident management locations are central to the role of incident management locations. It is important to set up a planning cycle that includes regular contact with the site(s) and EOC(s) where applicable. The liaison officer may handle contact between these locations and with communities and organizations as required.

For more information on additional incident management locations, see Appendix B – IMS facilities.

4.4 Multi-organization coordination

Multi-organization coordination is an important aspect of incident management. IMS recognizes that during an incident, stakeholder organizations must work together to make decisions. Decision-making may take place at the site or coordinated and carried out by EOC personnel. However, in the case of major or more complex incidents, communities and organizations should coordinate at more senior levels. IMS provides the structure and guidance for effective multi-organization coordination beyond an EOC.

Multi-organization coordination relies on a regular planning cycle. Coordination may be managed through regularly-scheduled meetings, teleconference calls and through the delivery of information products such as situation reports.

Multi-organization coordination may include:

  • sharing information to maintain situational awareness
  • sharing, prioritizing and coordinating resources
  • analyzing data and other relevant information
  • coordinating system-wide response efforts such as evacuation shelters
  • coordinating the movement and/or evacuation of affected individuals and families
  • coordinating places of assistance such as family and friends assistance centres (FFACs) and call centres
  • coordinating preventive and protective measures

Collaborative response networks

Multi-organization coordination is a key part of a collaborative coalition or network response structure (such as those within the health care sector). In network response structures, incident response organizations may work together in unified command (see Section 4.7 – Unified command (also known as unified coordination)) or maintain coordination and command of their own incident response effort and coordinate overall efforts.

Multi-organization coordination (MOC) groups

Multi-organization coordination (MOC) groups may need to be set up to help senior and elected officials and incident responders make policy-level decisions and support the sharing and management of resources. If used, MOC groups should consist of senior and elected officials from communities and organizations involved in an incident response. They can be pre-arranged or called upon as needed.

These groups are key to coordinating unity of effort during a complex, non-site-based incident affecting a large geographic area. The ability to coordinate across communities and organizations at the senior-level is crucial to maintaining unity of effort. Clear communications, effective and efficient collaboration and a flexible approach are also important factors in coordinating incident response efforts.

MOC groups should also maintain a planning cycle with regularly scheduled meetings or teleconference calls as well as routine information sharing methods such as situation reports.

Senior and elected officials

It is important to recognize that senior and elected officials play an important role in incident management. They are responsible for the safety and welfare of their community and the overall effectiveness and efficiency of incident response efforts.

Incident response personnel working in an EOC and at the site must share accurate and up-to-date information with the personnel responsible for briefing senior and elected officials. It is important to keep senior and elected officials informed about an incident, possible resource needs and other pertinent information. Effective and efficient communication between incident response personnel and senior and elected officials fosters trust and helps ensure that they have the information necessary to make informed decisions.

MOC groups can help to organize senior and elected officials and enhance unity of effort at the senior-level.

4.5 Single command

Many incidents are coordinated by a single incident commander (also known as an incident manager). Incident command led by a single incident commander has several advantages, such as quickly establishing incident objectives, strategies and tactics. This is especially important when timely decision-making involves life safety or damage to property and/or the environment.

Single command is generally the preferred form of incident management except in rare circumstances where unified command is more effective (see Section 4.7 – Unified command (also known as unified coordination)).

Single command occurs when the first arriving responder attends the scene of an incident. The first arriving responder is responsible for the coordination and command of an incident response and carrying out all IMS functions until additional incident responders arrive at the scene of an incident. A transfer of command may take place to a more experienced or senior-level responder representing the lead organization responsible for the incident response.

Responsibility for single command may be determined in one or all of the following ways by:

  • default if only one incident response organization is involved
  • design if multiple incident response organizations agree on which organization will be the lead organization and confirm single command
  • legislation if the incident response organization or jurisdiction has a legislative responsibility to become the lead organization in the incident response

4.6 Area command

Area command is set up to manage multiple sites. It can also be used to manage large or escalating incidents that include multiple response organizations. Each site and organization involved in an incident response will have their own incident management team.

Incident response organizations under area command will develop broad objectives for their assigned area and work with the incident management teams to coordinate individual incident objectives, strategies and tactics. Under area command, they will also set priorities for the sharing of critical resources across incident sites.

Situations which may require area command may include:

  • an infectious disease outbreak involving multiple jurisdictions and health partners
  • multiple terrorism related incidents
  • multiple incidents that occur at the same time such as a train derailment causing a release of hazardous materials in extreme weather conditions

In some incidents, area command will be a form of unified command. Section 4.7 – Unified command (also known as unified coordination) explains unified command.

4.7 Unified command (also known as unified coordination)

Multi-jurisdictional incidents require action from multiple response organizations that each have the accountability and responsibility to manage certain aspects of an incident. In incidents involving multiple incident response organizations, efforts should be made to agree on a single incident commander (see Section 4.5 – Single command).

However, in rare instances, the decision-making process in an incident may require the involvement of multiple response organizations, making it difficult to establish single command. In this case, there is the option to establish unified command. It is important to note that unified command may make the incident response process challenging, therefore its use should be rare. There may also be the need to invest more time and effort in maintaining a common operating picture to ensure that the decisions of multiple incident response organizations are informed by the same, shared information.

Unified command is when the management of an incident is shared between two or more lead organizations or jurisdictions through a common set of objectives, strategies and tactics.footnote 4 It may be established when:

  • organizations have an existing agreement to share command
  • the lead organization decides that a joint-approach will be more effective
  • organizations have overlapping jurisdiction and/or a legislative requirement that requires them to be in command
  • incident response organizations cannot agree about who should assume single command and there is a danger that response efforts will be uncoordinated with a risk to the safety of the public and responders, and/or the protection of property as a result

If unified command needs to be established, the lead response organizations should:

  • explicitly agree that they have entered unified command and the agreement to unified command should be verbally stated and signed in the written IAP
  • establish a common set of objectives, strategies and tactics
  • develop a single IAP

Unified command, by agreement, is responsible for the following:

  • selecting one spokesperson to represent unified command (when necessary)
    • there may be different spokespersons on different occasions but there will only be one spokesperson at a time
  • selecting one operations section chief from the incident response organization with the greatest jurisdictional or functional involvement. This individual will be responsible for implementing the single IAP
    • the operations section chief may have one or more deputy operations section chiefs
  • selecting one planning section chief to coordinate planning activities
  • establishing a schedule for regular coordination and planning meetings
  • setting up a single incident command post or management from a single EOC
  • developing a plan for coordinated public communications
  • determining the circumstances in which a return to single command may be required
  • documentation of actions and activities throughout the incident

Re-evaluation of unified command

As an incident progresses, the command structure may need to adapt to meet the needs of the incident. Unified command should be assessed regularly to ensure that it remains the best option to respond to an incident. A plan to return to single command should be developed to ensure an effective and efficient transition if necessary.

4.8 Transfer of command

In an incident, the first arriving responder becomes the incident commander and they are responsible for all of the IMS functions required for the response. The transfer of command may occur if:

  • a previously appointed or more appropriate responder is needed to fill the role of the incident commander
  • coordination and command must be handed over to a different response organization
  • there is a shift change

If the incident commander changes, a detailed hand-over briefing is required.

4.9 Working together – coordinating and collaborating effectively

The goal of coordination is to organize the incident response organizations into a single, cohesive response.

Working together effectively and efficiently requires:

  • coordinated planning, resource management and integrated information sharing and communications
  • coordination may be explicit (briefings, teleconference calls, incident action plans and other documents) or implicit (discussions, planning, liaising and working together)

It is important to note that collaboration can be:

  • vertical: between the site and an EOC
  • horizontal: between communities and organizations

At the site, the incident commander is responsible for coordinating response activities with incident response organizations as well as the personnel and resources they manage.

At an EOC, the EOC director is often responsible for coordinating support to the site, briefing senior and elected officials and information sharing with incident response organizations.

In a complex incident, multiple EOCs may come together in a coordinated network response. Individual response organizations set their own objectives to manage their response activities while ensuring communication, coordination and collaboration through regularly scheduled planning and information sharing meetings.

At the multi-organization coordination level, senior and elected officials must work together to establish and communicate policy-level priorities as well as authorizing resources and activities that require senior-level approvals.

A regular planning cycle should be established that includes all incident response organizations. A planning cycle includes:

  • frequent communication such as briefings between the incident commander and incident responders within the operations section
  • frequent communication between the incident commander and EOC directors
  • frequent communication between incident response organizations through liaison officers, teleconference calls and situation reports
  • inclusion of EOC personnel in an incident response planning process
  • inclusion of incident response organizations in the development and implementation of IAPs
  • ensuring coordinated communications and information sharing (e.g. posting the operational and planning cycles)

4.10 Complex incidents

Complex incidents involve many factors which cannot be easily analyzed and understood. They may be prolonged, large-scale and/or involve multiple jurisdictions. They may also require technical knowledge and/or training in combination with other needs and requirements.

When complex incidents involve mass casualties, they can overwhelm traditional response structures. The nature of an incident can make centralized response systems such as IMS less effective in the early stages of an incident.

In a highly complex, chaotic incident such as a mass humanitarian disaster, collaboration instead of command and control is important for an effective and efficient response. Unified command may be more effective because of the need for greater collaboration.

A coordinated and collaborative network approach can help communities and organizations respond more effectively and efficiently to complex incidents.

Importance of communication

In a mass humanitarian disaster or a complex non-site-specific incident such as a heat wave, internal and external communication across communities and organizations is an important step for an effective and efficient response. In the early stages of a complex non-site-specific incident, it is also important to create a common operating picture and develop ways to help communities and organizations collaborate effectively and efficiently.

A complex incident response requires:

  • sharing a high-level overview of situational awareness
  • leveraging the flexibility within IMS and adapting as needed
  • collaboration with incident response organizations (the liaison function is important in a complex incident response)
  • understanding and accepting that establishing coordination systems may take time
  • understanding and accepting that incident response organizations may have different objectives, but it is important that these objectives do not conflict with the objectives of other organizations

United Nations collaboration model for mass humanitarian disasters

The United Nations (UN) uses the On-Site Operations Coordination Centre (OSOCC) model to provide flexible incident management through effective collaboration during a sudden, chaotic or highly complex disaster response. It may be useful during a mass humanitarian disaster.

The UN Model is more decentralized and clusters operations based on recognized sectors of humanitarian activity. Cluster partners may include provincial and national organizations from all levels including international organizations and NGOs.


  • footnote[4] Back to paragraph During the 2015 Pan Am Games, nine participating police services coordinated security over a large geographic area. Unified Command was established to allow for the sharing of information and coordination of resources across multiple jurisdictions.