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System Coordinators
OES Region IV Multi-casualty Plan


When disaster strikes, local medical and health resources may be inadequate to meet the demand. The Medical/Health Mutual Aid System is designed to address this issue by facilitating the distribution of regional, state, and/or federal resources to the area(s) in need.

In California the Medical/Health Mutual Aid System is facilitated by grouping counties, referred to as Operational Areas, together to form six Mutual Aid Regions. Within a region, if disaster strikes, resources are distributed from the unaffected Operational Areas to the affected one.

San Joaquin County is part of Region IV. Other counties in Region IV include Alpine, Amador, Calaveras, El Dorado, Nevada, Placer, Sacramento, Stanislaus, Tuolumne, and Yolo.

View a detail map of Region IV >> Updated August 2015 (Designed to print 42" x 36")

View a map showing the six Mutual Aid Regions >>

California Public Health and Medical Emergency Operations Manual (EOM) July 2011 PDF Document

View training for California Public Health and Medical Emergency Operations Manual >>


Medical Health Operational Area Coordinator (MHOAC)
An individual appointed by a county Department of Health Director/Local Health Officer who is responsible in the event of a disaster or major incident where mutual aid is requested, for obtaining and coordinating services and allocation of resources within the Operational Area (county).

Click here to see a diagram that illustrates how the System Coordinators orchestrate the Medical/Health Mutual Aid process.


The current OES Region IV Multi-Casualty (MCI) Plan is comprised of 3 interdependent manuals: Manual I - Multi-Casualty Incident Field Operations; Manual II - Multi-Casualty Incident Control Facility Operations; and Manual III - Medical/Health Mutual Aid System.

The Adobe Acrobat Reader is needed to view and print the documents below. If you experience difficulty viewing the following documents you may download the Adobe Acrobat Reader for free from the Adobe web site.

Title Revision Date
Manual 1 - Multi-Casualty Incident Field Operations (PDF) June 1998
Manual 2 - Multi-Casualty Incident Control Facility Operations (PDF) February 1998
Manual 3 - Medical/Health Mutual Aid System (PDF) March 2005


The San Joaquin County Administers EMResource for the Region. The following documents have been developed to assist with just-in-time training and user development.

  • Powerpoint presentation designed for just-in-time training for creating MCI bed polling for hospitals in Region IV, and including Sacramento Hospitals. This should be viewed by Control Facilities and Receiving Hospitals.
  • MP4 video (silent) demonstrating MCI Bed Polling including Sacramento area hospitals, same video in just-in-time training above without the power point.
  • PDF document, based on the above powerpoint, without the video.
  • EMResource Quick Reference Guide for MCI Event Polling by Control Facilities.