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Calling 911

Calling 911

What to expect when you call 911

In Halton, calls to 911 go to the Mississauga Central Ambulance Communications Centre (CACC), which handles incoming 911 calls and dispatches ambulances. This process is enabled by the Medical Priority Dispatch System, which has become the industry standard for patient triaging across the world. 

This system is a medically validated tool used for the accurate and safe identification of the most critical and life-threatening situations. The tool supports Ambulance Communication Officers (ACOs) as they make critical decisions on when and where to dispatch ambulances.

Accurately prioritizing calls is critical to ensuring patients receive the right response and the right care, at the right time. If you call 911 with a life-threatening medical emergency, you will receive help first and as fast as possible. Whatever your medical condition, help is always on the way. 

What happens when you call 911

  • The 911 emergency dispatcher will ask if you need police, fire or ambulance.
  • An Ambulance Communication Officer (ACO) will ask you several questions: your name, what happened, where you are and a phone number to reach you. Stay calm, listen to the questions and answer them as best you can.
  • Tell the ACO exactly what happened. If someone is experiencing a life-threatening condition, they will send paramedics to your location first and as fast as possible while the ACO continues to gather information.
  • The ACO is a highly trained professional who will help you while paramedics are on the way.
  • Try to remain calm. Until paramedics arrive, the ACO may call back periodically to check on you.
  • If your condition changes, or you decide to reach the hospital on your own, please call 911 to inform the ACO.

Using 911 services

  • If you have a medical emergency or you’re not sure how serious your health concern is, call 911.
  • Calling 911 does not change when you will receive care at the hospital. Emergency Room staff decide when to see you based on your illness or injury, no matter how or when you arrive.
  • If you do not need immediate care where you are and can travel safely, there are many ways to reach the emergency room, such as family, friends, taxis and rideshare apps.

If you are experiencing a non-emergency and think you should be seen by a doctor:

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