Gas Smell Furnace Toronto: Leave First, Then Call
If you smell gas near your furnace in Toronto, leave the building now without switching anything on or off, and call Enbridge Gas at 1-866-763-5427 from outside; if the smell is strong or you hear hissing, call 911 as well. This page is for homeowners in Toronto and the GTA dealing with a possible furnace gas leak or related safety concern, because even a small ignition source can trigger an explosion.
Once Enbridge has made the property safe, call 2HVAC and we will connect you live to a licensed technician from our network for repair. Below, you’ll find the emergency steps to take, what not to do inside the home, how Enbridge and emergency services handle the immediate risk, and what to expect when it’s time for furnace repair and safety checks.
What to do, in order
Get everyone out
Take people and pets outside and away from the building, and move a safe distance from the home immediately after you leave. Leave the door open behind you if you can do so on your way out.
Do not touch switches, phones or appliances inside
Electrical switches, including a light switch, a thermostat, a doorbell, a garage door opener or a phone, can spark. Do not start a car in an attached garage. Do not go back for anything. Make every call from outside. Avoid open flames as well as anything that could spark.
Call Enbridge Gas from outside: 1-866-763-5427
The gas utility's emergency line is answered around the clock and the call is free. They will send a technician to find and stop the leak. If the smell is strong, or you can hear gas escaping, call 911 as well.
Stay out until you are told it is safe
Do not go back in to open windows or to shut the gas off yourself. The utility's technician does that, checks the appliances, and tells you when the building is clear.
Then call us for the repair
Once the property is safe, the source still has to be fixed: a furnace gas valve, a connector, a burner assembly, a section of gas line, or gas piping. A faulty valve or small leak can still release gas even when the gas furnace is off. Common causes of gas smells also include a cracked heat exchanger or loose connections that let gas escape from natural gas appliances. Our assistant confirms what the utility found and your postal code and connects you live to a technician whose team holds the TSSA gas certificate that work requires.
Call a professional immediately if…
- You smell gas at all. This whole page is the 'call immediately' case; call the gas utility first, not an HVAC company.
- A carbon monoxide alarm has sounded. Leave, call 911, and have every gas appliance checked before using them again because carbon monoxide exposure and carbon monoxide poisoning both need urgent treatment.
- A gas appliance has been shut off and tagged by the utility and needs repair before it can be relit.
- The furnace pilot or igniter keeps failing and there is any smell of gas around it. A persistent gas smell around a gas furnace needs immediate attention, not repeated restart attempts.
- You feel dizzy, nauseous or have a headache that improves when you go outside. That is carbon monoxide until proven otherwise, and those are warning signs that can point to incomplete combustion or venting problems; a clogged vent can cause incomplete combustion and gas odours.
What happens once you call
The utility stops the leak and makes the property safe; it does not repair your appliances. That is the technician's job. Anything on the gas side of a furnace, from the shutoff valve to the burners to the venting, must be done by someone holding a TSSA gas certificate, and every contractor in our network agrees in writing to hold the licences the province requires. Ask for the number.
Once repaired, the technician relights and tests the appliance and checks for leaks with a detector, not a match. If the furnace was the source and it is old, expect an honest conversation about replacing rather than repairing it. Ask them to check the heat exchanger and the venting while they are there.
Why the first step is leaving, not investigating
Natural gas is odourless. The smell you notice is mercaptan, added deliberately so a leak is detectable, and it is detectable at concentrations far below anything dangerous. That is the point of it: by the time you can smell it you have warning, not an emergency, provided you act on the warning rather than hunting for its source.
What makes a leak dangerous is ignition, and the ignition sources are ordinary. A light switch, a garage door opener, a phone, a doorbell or a fan can each produce enough of a spark. That is why the instruction is to leave without touching switches and to call from outside — not caution for its own sake, but because operating anything electrical is the specific thing that turns a smell into an incident.
Enbridge attends suspected leaks at no charge, around the clock. There is no bill for being wrong, and no version of this where calling was the expensive mistake.
Questions
What does a natural gas leak smell like?
Rotten eggs or sulphur. Natural gas has no smell of its own; the utility adds the odour specifically so leaks get noticed. A brief whiff at a stove burner as it lights is normal. A persistent smell anywhere, especially near the furnace, water heater or gas meter, is not.
Should I turn off the gas at the meter?
Only if you already know how, the valve is outside, and you can reach it on your way out without going back in. Otherwise leave it to the utility's technician. The three things that matter are getting out, making no sparks, and calling Enbridge from outside.
Who repairs the leak after Enbridge has been?
The utility stops the gas and makes the property safe, and may tag an appliance as unsafe to use. The repair itself is done by a contractor holding a TSSA gas certificate. Call us once the building is cleared and our assistant connects you live to a technician whose team holds that certificate.
What is the difference between a gas leak and carbon monoxide?
A gas leak is unburnt natural gas escaping, and you can smell it. Carbon monoxide is produced by burning and has no smell at all, which is why detectors exist. A cracked heat exchanger or a blocked vent can produce carbon monoxide with no gas smell whatsoever. Treat an alarm as an emergency even if you smell nothing.