Marie Lucinger-Busic says she doesn't mind sharing her wedding anniversary with the Mississauga train derailment.

On Nov. 10, 1979, as her guests were leaving her reception in west-end Toronto, she says many noticed a red sky over Mississauga and wondered, "What's going on there?"

She only found out there was an evacuation underway, with thousands of residents forced to spend the night in an emergency shelter, when many of her guests showed up at a luncheon reception the next day still wearing their formal wear.

"Some of these ladies were still in the same gowns and shoes," she told CBC Toronto.

She says they jokingly blamed her and her husband for the disaster "because they had no chance to go change."

Lucinger-Busic's story is just one of many that historians with Heritage Mississauga have collected as part of an exhibit commemorating the 40th anniversary of the disaster — which started as a train derailment, explosion and fire, and eventually forced almost a quarter of a million people out of their homes — at the time, the largest peacetime evacuation in North American history.

Fire crews battle propane tanker cars on fire on Nov. 11, 1979 (CBC)

Spread over two locations — the Bradley Museum at 1620 Orr Road and The Grange at 1921 Dundas Street West —the Mississauga Miracle exhibition brings together photos, artifacts and memorabilia from the 1979 disaster, along with artwork inspired by the experiences of Mississauga residents who lived through the ordeal.

"This is probably the most significant chapter of our local history," said Matthew Wilkinson, one of the curators of the collection.

'A defining moment'

"It becomes a defining moment of a generation and of a community."

It was certainly a defining moment for former Mississauga mayor Hazel McCallion, 98, who was roused from her bed the night of the train disaster and went three days without sleep as she helped to coordinate the city's emergency response.

"I don't know of any other thing that has happened in my 36 years [as mayor] that was as serious and as demanding and as stressful as the Mississauga derailment," McCallion told CBC News.

Marie Lucinger-Busic shares the date of her wedding anniversary with the Mississauga Train derailment. (Paul Borkwood/CBC)

It all began at 11:53 p.m. when a Canadian Pacific freight train with several tanker cars full of dangerous chemicals derailed on Mavis Road, between Burnhamthorpe Road and Dundas Street.

Within minutes, one of the tanker cars carrying propane ruptured and exploded, sending a massive fireball into the suburban sky.

As firefighters responded, they were met by several more explosions. They soon issued evacuation orders for nearby residents. Within hours, hundreds of people were being housed in the Square One shopping mall, which was opened up overnight for use as an emergency shelter.

Former Mississauga mayor Hazel McCallion, 98, was woken up the night of the derailment. She wouldn't get any sleep for the next three days. (Oliver Walters/CBC)

"When I got dressed," said McCallion, "I rushed down to Square One and saw these people there. And they had come in their nightclothes. People left without their prescriptions. It was a very serious situation, so we had to get organized."

As emergency crews provided food and opened drug stores to fill prescriptions, firefighters battling the flames at the train wreck soon realized they were dealing with a much more dangerous, and potentially lethal situation: a tanker car carrying chlorine gas was buried underneath some of the burning wreckage.

"The danger with chlorine," explained Wilkinson, is that if that car had exploded "it would have been catastrophic. Chlorine is heavier than air. It is a gas that if inhaled will burn out the inside lining of your lungs."

Mississauga residents spending the night at a makeshift shelter at Square One shopping centre on Nov. 11, 1979. (CBC)

He says emergency crews kept tabs on the wind direction, then realized they had to quickly expand the evacuation order because of the danger to the public.

"This was a deadly toxic gas that will kill people without a doubt," he said.

Within eight hours of the disaster, Mississauga started making plans to move all 900 patients from its local hospital. Residents sheltering at Square One were moved to nearby high school gymnasiums.

The Mississauga train derailment as seen from a helicopter on Nov. 11, 1979. (CBC)

Peel Regional police vehicles started driving through neighbourhoods, warning residents by loudspeaker to prepare to leave. Officers would then follow door-to-door making sure residents were on their way.

Twenty-four hours after the first explosions, emergency officials had coordinated the evacuation of 240,000 residents from an area stretching from east-end Oakville to west-end Etobicoke. Police barricades shut down the Queen Elizabeth Way and other major roads leading into the city.

Propane tanker cars on fire in Mississauga, ON. November 11, 1979 (CBC)

Mayor McCallion declared the city "closed for business."



Wilkinson's family took part in that evacuation. He says his mother didn't even bother waking him as they fled in the middle of the night to move in with friends.

"I went to bed in Mississauga and woke in up Oakville."

He says his father was working at a hospital in Hamilton that night and had no idea where his wife had taken their children.

An empty shopping mall parking lot after two thirds of Mississauga was evacuated. (CBC)

"It took him half a day to find her. Everyone has cell phones now but that wasn't the case in 1979."

What's more, he says most people fled their homes without packing much, assuming the evacuation order would be lifted after a couple of hours.

Few made arrangements for the pets and animals they left behind, and McCallion says the city had to make arrangements for that as well.

"No animals died," she said. "We had people come to city hall and deliver the keys [to their homes] and the firefighters went into their homes where dogs or cats were left and they were fed."

Historian Matthew Wilkinson of Heritage Mississauga calls the Mississauga train derailment 'a defining moment' for the community. (Paul Borkwood/CBC)

Emergency crews eventually put out the fires and then patched a rupture in the chlorine tanker car. Once the chemicals were pumped out, the first families were allowed to return to their homes. After six days, the last of the evacuation orders were lifted.

"The police department and the fire department organized things in a magnificent way," recalled McCallion. "When I think back on it they really were heroes of the derailment."

The Mississauga Museum exhibit features stories from many of the first responders.

It also features some less-serious artifacts, from a 45-RPM novelty song recorded about the disaster to a collection of t-shirts printed so residents could proudly declare they survived the evacuation.

Commemorative t-shirts on display at the Museums Mississauga exhibit. (Paul Borkwood/CBC)

"We can look back and say it was a positive thing because the outcome was largely positive," said Wilkinson.

"The people that we talk to in their 40s or 50s now were children then, and it has largely been remembered as a fun adventure."

Lucinger-Busic is glad there was no loss of life to dampen both the memories of the evacuation, and of her wedding.

She says her friends always say it's easy to remember her anniversary, because images of the disaster are often on TV that day.

They see those images, the wedding pops into their mind, and then they think, "Let's send a card," she jokes.