If you’ve ever stood at the base of the CN Tower and looked up—way up—you’ve probably felt that slight dizzying sensation. It’s a concrete giant. For decades, it held the title of the world’s tallest free-standing structure. But there’s a specific bit of Toronto lore that keeps resurfacing in group chats and local history threads: the CN Tower fire.
Wait, was there actually a fire?
Yes. And no. It depends on which year you’re talking about and how you define a "fire" in a building that is basically a massive lightning rod. Most people are thinking of the 2017 incident that sent social media into an absolute frenzy, but the history of smoke and sparks at 290 Bremner Blvd is actually a bit more technical than just a "building on fire" headline. It’s a story of high-altitude electrical failures, terrifyingly high climbs for firefighters, and the reality of maintaining a 553-meter icon.
The 2017 CN Tower Fire: A Night of High-Altitude Stress
In the early morning hours of August 16, 2017, the Toronto Fire Services got a call that no one wants to receive. Smoke was coming from the main pod. Now, imagine being a first responder and looking at a structure that tall. You can’t just pull a ladder truck up to the 114th floor.
The CN Tower fire wasn't a raging inferno, but in a building like that, any smoke is a nightmare scenario. Around 4:00 AM, a fire broke out in the antenna mast, specifically involving the broadcasting cables. It was an electrical issue. Basically, a "hot spot" flared up in the wiring that feeds the massive transmitters at the top.
Firefighters had to lug heavy equipment up to the observation level and then climb even further. We aren't talking about a casual elevator ride here; when there’s a fire, elevators are a gamble. They had to navigate the "Radome"—that white donut-shaped area—to get to the source.
District Chief Stephan Powell noted at the time that the fire was contained to the cable transition area. They actually had to cut power to the giant FM and TV transmitters. If you were trying to listen to the radio in the GTA that morning, you might have heard nothing but static.
Why it was so hard to put out
Honestly, it’s about the geography of the tower itself. Firefighters used dry chemical extinguishers because you can't just spray tons of water on high-voltage electrical equipment 400 meters in the air. That’s a recipe for a secondary disaster. They eventually managed to extinguish the smoldering cables by about 7:00 AM.
The most "Toronto" part of the whole thing? The CN Tower’s official Twitter account was relatively quiet while people on the ground were posting grainy cell phone videos of flashing lights at the summit. It felt like the city was holding its breath.
Was there a fire during construction?
Actually, yes. If you dig back into the archives of the 1970s, the CN Tower fire history starts before the building was even finished. On November 9, 1973, while the tower was still a concrete stump under construction, a fire broke out in the wooden formwork at the top of the structure.
At the time, the tower was about 200 meters tall.
It was a cold November day. Tarpaulins and propane heaters were being used to keep the concrete warm so it would cure properly in the Canadian winter. Something caught. The fire department couldn't reach it. They basically had to wait for the fire to burn itself out because there was no way to get water that high up with the infrastructure they had at the time.
It didn't do much structural damage, but it terrified the workers. Imagine being on a swaying concrete platform in 1973 with a fire burning right next to your only way down.
The Lightning Factor: Fire or Just Physics?
People often mistake the CN Tower's frequent lightning strikes for fires. It makes sense. You see a massive flash, a plume of what looks like smoke, and you assume the worst.
The tower is struck by lightning an average of 75 to 100 times a year.
Usually, the energy is bled off through a massive grounding system. Long copper strips run down the length of the tower and into the ground. However, occasionally, a strike is so powerful it can "scorch" the outer coating or cause a brief electrical surge that mimics the smell of a fire. This leads to dozens of false alarms every year. Toronto Fire crews are used to it, but they treat every call like it’s the real deal because the stakes are simply too high.
What Most People Get Wrong About Tower Safety
You might think that a fire in the CN Tower would result in a "Towering Inferno" style disaster. But the building is mostly concrete and steel. There isn't a lot of "fuel" inside the shaft.
The real danger in any CN Tower fire scenario is the chimney effect.
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Because the tower is a long, vertical hollow tube, a fire at the base could theoretically pull air upward at incredible speeds, turning the elevator shafts into blowtorches. This is why the fire suppression systems in the tower are some of the most redundant in the world.
- Water Reservoirs: There are massive water tanks located at the 335-meter and 346-meter levels.
- The "Slow Burn" Design: The concrete is thick enough to withstand hours of intense heat without losing structural integrity.
- Dedicated Fire Lifts: There are specific elevators designed to operate even when the rest of the building's power is cut.
The 2017 Aftermath
After the 2017 electrical fire, the tower underwent a massive audit of its broadcasting equipment. They realized that some of the old analog cabling was becoming a liability. Much of that was stripped out and replaced with modern, lower-heat fiber optics and better-insulated power lines.
It’s expensive. It’s tedious. But it’s the only way to keep a 50-year-old concrete needle from becoming a hazard to the millions of people who walk underneath it every day.
How to Stay Informed During a Toronto Emergency
If you see smoke near the top of the tower, don't just rely on TikTok. Toronto’s emergency services have become much better at communicating since the 2017 incident.
- Check Toronto Fire Services’ (TFS) Active Incidents Feed: This is the most accurate way to see if crews have actually been dispatched.
- Listen for the Sky-High Alarms: The tower has an incredibly loud external PA system for the surrounding plaza.
- Avoid the Area: During the 2017 fire, the biggest headache for police wasn't the fire itself—it was the thousands of tourists and commuters clogging the streets to take photos, which blocked emergency vehicles.
The CN Tower fire of 2017 serves as a reminder that even icons aren't invincible. It’s a complex machine that requires constant vigilance. Whether it’s a construction accident from the 70s or a shorted-out cable in the 2010s, the tower has proven to be remarkably resilient.
If you're planning a visit, don't let the history of small electrical fires scare you off. The building is arguably one of the safest places in the city due to the sheer amount of engineering oversight it receives. Just maybe check the weather forecast for lightning first—not because of fire, but because the view is much better when you aren't inside a giant conductor.
Actionable Steps for the Curious
- Check the official CN Tower "EarthCam": If you hear a rumor of a fire, the live 360-degree cameras on the tower's website are usually still running and provide the clearest view of the exterior.
- Monitor "CP24" or "CityNews": For local Toronto emergencies, these outlets typically have helicopters over the scene faster than any national news agency.
- Understand the "Radome": If you see crews working on the white "bubble" area, that’s where the 2017 fire occurred. It’s a high-maintenance zone, so activity there is normal and doesn't always mean an emergency.
- Look at the base: If there is a real emergency, the TTC usually diverts the 504 King streetcar and the 510 Spadina line to clear the "fall zone" around the base of the tower.