Emergency Medical Services (EMS) Agency

About Us

The Los Angeles County Emergency Medical Services Agency serves as the lead agency for the emergency medical services system in the County and is responsible for coordinating all system participants in its jurisdiction, encompassing both public and private sectors. In California, counties have been given the primary responsibility for assuring that EMS systems are developed and implemented and for designating a local EMS agency.

The EMS Agency is responsible for planning, implementing, monitoring and evaluating the local EMS system. This includes establishing policies, addressing the financial aspects of system operation, and making provisions for collection, analysis, and dissemination of EMS related data. In addition, the EMS Agency is responsible for establishing operational policies and procedures; designating EMS base hospitals and specialty care centers, such as trauma centers; developing guidelines, standards and protocols for patient treatment and transfer; implementing a prehospital ALS program; certifying and accrediting prehospital medical care personnel; and approving EMS personnel training programs.

Los Angeles County has one of the largest EMS systems in the nation and, as one of the first to be developed, is known nationally and worldwide as a leader in the field of prehospital care. The system utilizes over 18,000 certified EMS personnel employed by fire departments, law enforcement, ambulance companies, hospitals and private organizations to provide lifesaving care to those in need 24 hours a day, seven days a week.

Cathy Chidester, RN, MSN

Cathy Chidester, RN, MSN

Contact Information:

Los Angeles County EMS Agency

10100 Pioneer Blvd., Suite 200Santa Fe Springs, CA 90670

Email:     cchidester@dhs.lacounty.gov
Phone:    (562) 378-1604
Fax:        (562) 941-5835


Cathy Chidester has over 30 years experience in the field of emergency medical services, 23 of which was spent working for the Los Angeles County EMS Agency. She began her career in the EMS Agency as a paramedic instructor with the Paramedic Training Institute (PTI) and worked in various prehospital care programs before being appointed as Assistant Director in 2002.

Since 2006 she has served as the Director of the EMS Agency and oversees the daily operations of the largest multi-jurisdictional EMS system in the nation.
Prior to entering county service, Cathy worked in the emergency department at several area hospitals and held positions as the trauma nurse coordinator and pediatric unit charge nurse at Presbyterian Hospital in Whittier. She soon became interested in teaching and taught EMTs at Rio Hondo College until moving to PTI in 1990.
Because of her extensive background in emergency medical services, she has a strong working knowledge of the system and its various components.
“I have always enjoyed EMS because of the fast-paced environment and the ability to think, act, and get results quickly. I also get a great deal of job satisfaction from developing programs and creating an environment which fosters teamwork and patient advocacy.” 

-Cathy Chidester

Historical Timeline 1966
  • 1966
  • National Academy of Sciences – National Research Council publishes a report titled Accidental Death and Disability: The Neglected Disease of Modern Society , which recommends the use of pilot programs to determine the efficacy of providing physician-staffed ambulances for care.
  • Highway Safety Act of 1966 establishes national standards for inspections of used emergency services vehicles.
  • National Traffic and Motor Vehicle Safety Act of 1966 specifies ambulance design and construction.
  • ______________________________________________
  • 1967
  • Dr. Frank Pantridge from Belfast, Ireland publishes the first study defining a Mobile Coronary Care Unit.
  • ______________________________________________
Historical Timeline 1969
  • 1969
  • Dr. Walter Graf begins a Mobile Coronary Care Unit program at Daniel Freeman Hospital in Inglewood-Centinela. The “Heart Car,” donated by McCormick Ambulance and equipped with a cardiac monitor, defibrillator and radio communication equipment begins service.
  • Board of Supervisors meet with community leaders and decide to train fire department personnel as paramedics.
  • ______________________________________________
Historical Timeline 1969
  • September 12, 1969
  • The first paramedic class begins training at Harbor General Hospital under Dr. J. Michael Criley and Critical Care Unit nurse Carol Bebout)._____________________________________________
Historical Timeline 1969
  • December 8, 1969
  • The first LA County Fire rescue unit, Squad 59, officially goes into service. It is based on the grounds of Harbor General Hospital and is manned by two newly trained paramedics on each shift.
  • Work begins on a state bill to allow paramedics to provide advanced medical life support without the direct supervision of a nurse or physician. It is introduced to both houses of the State by Senator James Wedworth and Assemblyman Larry Townsend.
Historical Timeline 1970
  • July 14, 1970
  • The Wedworth-Townsend Paramedic Act is signed into law by Governor Ronald Reagan. California becomes the first state to adopt legislation permitting paramedics to provide advanced medical life support.
Historical Timeline 1970
  • September 1970
  • The first paramedics graduate from the Paramedic Training Institute.
  • ______________________________________________
Historical Timeline 1971
  • May 11, 1971
  • TV producer Robert Cinader becomes interested in developing new series regarding rescue for NBC and visits Los Angeles County Fire Station 7 and Station 36.______________________________________________
Historical Timeline 1972
  • January 1972
  • The TV series “Emergency!” is first televised. The series raises public awareness of the paramedic program throughout the country.
  • 1973
  • The Emergency Medical Services Systems Act of 1973 is signed into law, establishing federal grant funding for EMS systems.
  • 1974
  • Dr. Ronald Stewart, an emergency medicine physician, is placed in charge of the Paramedic Training Institute. He modifies the paramedic curriculum and writes the first paramedic training manual.
  • Late 1970s
  • Continuing education programs are put into place. Paramedics are now required to recertify through written and skills examinations.
  • ______________________________________________
  • Late 1979
  • The EMS Commission is established by County Ordinance
  • The Board of Supervisors adopts the Advanced Life Support (ALS) Unit Staffing Policy, which requires two licensed paramedics to staff any ALS Unit.
  • ______________________________________________
County seal
  • November 1980
  • The Emergency Medical Service and Emergency Medical Care Personnel Act is signed into law, mandating state responsibility for emergency medical services by designation of a local EMS Agency.
  • The Los Angeles County Board of Supervisor authorizes the Department of Health Services to fill the role of EMS Agency and becomes responsible for the overall coordination of emergency services in LA County.
  • ______________________________________________
  • December 15, 1983
  • The first eight Level 1 trauma hospitals are designated and activated by the Board of Supervisors.
  • ______________________________________________
  • Late 1983
  • The US Supreme Court rules that local governments granting monopolies would not be exempt from antitrust laws unless policies were clearly articulated.
  • 1984
  • The EMS Act is amended to allow local EMS Agencies to create exclusive operating areas for private EMS providers such as ambulance companies.
  • 1984-1985
  • Hospitals with the capability of handling specialized needs of children are designated as Emergency Departments Approved for Pediatric Critical Care Centers
  • Late 1980s
  • Testing and certification of paramedics is transferred from the local counties to the state.
  • ______________________________________________
  • July 1994
  • By statute, paramedic certification is changed to licensure and testing is eliminated from the relicensure process.
  • ______________________________________________
  • 1995
  • The Paramedic Training Institute becomes affiliated with EL Camino Community College District.
  • ______________________________________________
  • March 1997
  • The EMS Agency designated the first 5 Sexual Assault Response Team (SART) Centers.
  • ______________________________________________
  • September 1997
  • Standing Field Treatment Protocols (SFTPs) were approved by the EMS Agency for implementation for Los Angeles Fire Department. SFTPs allowed paramedics to provide emergency life-saving treatment without contacting a paramedic base hospital.
  • ______________________________________________
  • February 2002
  • The EMS Agency received the first year of federal grant funding to prepare hospitals to respond to disasters under the Hospital Preparedness Program.
  • ______________________________________________
  • August 2003
  • Subsequent to the implementation of pediatric specific Title 22 trauma center requirements, the EMS Agency designated the first 5 Pediatric Medical Critical Care Centers.
  • ______________________________________________
  • June 2004
  • The EMS Agency, under the Hospital Preparedness Program designates 11 hospitals as Disaster Resource Centers to coordinate disaster planning and preparedness activities in their geographical areas. The DRC program becomes the foundation of emergency preparedness activities for the healthcare community.
  • ______________________________________________
  • December 1, 2006
  • The first three STEMI Receiving Centers (SRCs) are designated by the EMS Agency
  • ______________________________________________
  • June 2007
  • Purchased Mobile Medical System comprised of a 10 bed emergency department tractor/trailer and support vehicle and an 100 bed tent facility.
  • ______________________________________________
  • April 2009
  • The first 10 Approved Stroke Centers were designated by the EMS Agency.
  • ______________________________________________
  • February 2012
  • The EMS Agency implemented regionalized system of care to cardiac arrest patients who sustain a return of spontaneous circulation (ROSC). Patients with ROSC were transported to the STEMI receiving centers for possible hypothermia or percutaneous coronary intervention.
  • ______________________________________________
SideWalk-CPR           June 7, 2012

  • The EMS Agency partnered with the American Heart Association, local hospitals, EMS Provider Agencies and other Southern California EMS Agencies to sponsor the inaugural SideWalk CPR day.         
  • December 2014
  • Designation of two Ebola Treatment Hospitals.
  • ______________________________________________
LA County Approved Stroke Centers           December 2017

  • Comprehensive Stroke System approved by the Board of Supervisors with the first 10 Comprehensive Stroke Centers designated

  • Provider Impression based Treatment Protocols Implemented
Marianne Gausche-Hill

Marianne Gausche-Hill, MD, FACEP, FAAP
EMS Agency Medical Director

Contact Information:


Los Angeles County EMS Agency
10100 Pioneer Blvd., Suite 200Santa Fe Springs, CA 90670

Email:     mgausche-hill@dhs.lacounty.gov
Phone:     (562) 378-1600
Fax:        (562) 941-2306


Dr. Gausche-Hill joined the EMS Agency as the Medical Director on July 1, 2015.  She also holds the positions of Professor of Clinical Medicine and Pediatrics at the David Geffen School of Medicine at UCLA and the EMS Fellowship Director at Harbor-UCLA Medical Center.   Dr. Gausche-Hill currently serves on the American Board of Emergency Medicine Board of Directors.

She is nationally known for her work as an EMS researcher and educator, and for her leadership in the field of EMS and pediatric emergency medicine.  She is best known for her study of pre-hospital airway management for children published in JAMA 2000 and her work on the National Pediatric Readiness Project published in JAMA- Pediatrics in 2015.

Dr. Gausche-Hill has an illustrious career in emergency medicine and has been recognized for her many contributions to this field of medicine, which include the following:

  • In 2004 awarded the National Education Award in Emergency Medicine by the American College of Emergency Physicians (ACEP)
  • In 2005 awarded the Martha Bushore-Fallis APLS award from the American Academy of Pediatrics (AAP),
  • In 2007 awarded the Emergency Medical Services for Children Heroes Award for Lifetime Achievement by the Health Resources and Services Administration, The Federal EMS for Children Program
  • In 2008 named one of the Heroes of Emergency Medicine by ACEP
  • In 2010 finalist for the Daily Breeze Newspaper’s Healthcare Provider of the Year
  • In 2011 Honorable Mention Speaker of the Year for ACEP
  • In 2012 awarded the Steve Miller Education and Mentorship Award by the AAP
  • In 2013 awarded Woman of the Year by the National Association of Professional Women and the Distinguished Service in EMS Medal by the State of California
  • In 2014 awarded the Outstanding Contribution in EMS award as well as the Speaker of the Year Award by ACEP.