Mississauga Train Derailment (1979)

For more information about the Mississauga Train Derailment view the complete file in the Local Archives section of the Canadiana Room on the third floor in the Central Library.


The accident occurred on the night of November 10, 1979 when a 106 car freight train carrying explosive and poisonous chemicals was derailed at the intersection of Mavis Road in Mississauga.

The disaster was well covered by the press. 79 writers contributed articles or reports, and 305 photographs were reproduced, relating to the derailment, explosion, evacuation, and government enquiry. This is a brief synopsis of that night.

Excerpt from: DERAILMENT. The Mississauga Miracle

Saturday November 10, 1979
This was to be one of the many dull, uneventful runs. A 106-car train carrying a mixed cargo, including dangerous chemicals, rolling through Ontario’s rich farmland and heavily-populated areas to rail-yards in the northeast end of Metropolitan Toronto. And so it was, until just before midnight, November 10, 1979.

Canadian Pacific Railway train 54 began its fateful journey in early afternoon at Windsor in the southwestern part of Ontario. It stopped in Chatham 90 minutes later where it picked up cars from a train arriving from Sarnia. Some of these cars were carrying caustic soda, propane, chlorine, styrene and toluene, a cargo which causes environmentalists to shudder and warn of horrendous derailment nightmares.

After connecting the tank cars, the train left Chatham at 6 p. m. to travel east to London where crews were changed before it continued its journey towards Toronto.

As the train passed the Milton area, about 40 kilometres from the outskirts of Metro Toronto, lack of lubrication in a wheel bearing apparently started to spell trouble. On one car, the journal box at each end of the axle, where friction builds up between the moving axle and the car above, was an old-fashioned type, needing lubrication by oil. Modern freight cars have roller bearings, which don’t heat up as do the older friction or journal bearings. However, when the journal box lacks lubrication, tremendous heat builds up. In trainmen’s vernacular, the overheated journal box becomes a “hot box”.

Residents living beside the tracks later reported seeing smoke and sparks coming from the middle section of the train. As the train progressed, people living closer to Mississauga, a community just west of Toronto, thought part of the train was on fire. Friction burned the journal bearing causing the stub of the axle to break off. Immediately after the train passed the Burnhamthorpe Road level crossing, the 33rd car – the one with the hot box and with a cargo of toluene – lost one of its four axles, complete with glowing wheels. The set of wheels crashed through a fence and landed in the backyard of a house, about 15 metres from the tracks and three kilometres from the Mavis Road crossing.

The train went past a further residential section of apartment buildings and suburban homes with its undercarriage hanging until reaching the Mavis Road crossing in a light industrial area about 30 kilometres from downtown Toronto. The dangling undercarriage left the track three minutes after losing the axle. Twenty-three other cars followed the tanker, causing a deafening crash and squeal of iron as cars collided at the Mavis Road crossing. On impact, some propane cars burst into flames. That was 11:53 p.m. – the beginning of a tense week for thousands of Mississauga residents.

As the derailed train’s tank cars became twisted and tangled, tankers containing styrene and toluene were punctured, spilling their chemicals on to track beds. Within a minute, flammable liquids and vapors ignited, causing a massive explosion of a tank car. The yellowish-orange fire rose to a height of 1,500 metres and could be seen 100 kilometres away. The fire was fed by six dangerous ingredients – 11 tank cars of propane, four with caustic soda, three with styrene, three with toluene, two box cars with fiberglass insulation and one with chlorine. While chlorine is non-combustible in air, most combustible materials will burn in chlorine as they do in oxygen. Liquid propane, styrene and toluene are flammable while caustic soda is not combustible, but in solid form and in contact with moisture or water, it may generate sufficient heat to ignite combustible materials.

As the flames erupted, trainman Larry Krupa jumped out of the engine and ran towards the derailed portion of the train. He closed a cock on the 32nd car which permitted engineer Keith Pruss to drive the front part of the train eastward along the tracks out of danger.

Citizen reaction was immediate. Police and fire department switchboards lit up with a flood of calls alerting them of the derailment. Officers on patrol and at the station closest to the derailment saw the fire. Within minutes, firefighters began connecting hoses and police were setting up roadblocks at the derailment site. Both reported to their headquarters a similar message – more help was needed urgently.

Sunday, November 11,1979
As firefighters made preliminary plans to battle the fire, a violent explosion at 12:10 a.m., caused by a propane tanker blowing up, showered the surrounding area with large chunks of metal. The force of the explosion knocked police officers, firefighters and curious onlookers to the ground.

Near the explosion, a green haze was seen drifting in the air. Along a kilometre stretch, windows were shattered and three greenhouses and a municipal recreational building destroyed.

Between five and 10 minutes later, a second explosion erupted. A bleve (boiling liquid expanding vapor explosion) in another propane tank car hurled the car in the air, spewing fire and landing in a clear area. It tumbled across a field before coming to rest 675 metres northeast of the Mavis Road crossing.

Five minutes later, another bleve in a propane car occurred with one end of the car travelling about 65 metres.

By now, CP Rail dispatchers’ offices in London and in Agincourt, northeast of Toronto, the ultimate destination of train 54, were notified of the derailment through CP’s radio system.

Meanwhile, hasty telephone calls were also placed to Mississauga Fire Chief Gordon Bentley, Police Chief Douglas K. Burrows, and the Ontario Ministry of the Environment. Mayor Hazel McCallion telephoned the police after her son climbed on the roof of the family house in nearby Streetsville to describe the blazing fire.

Police and fire officials acquired the train’s manifest, a description of the cargo and emergency procedures, from the conductor, but it was unintelligible. Another copy was subsequently requested from the CP Rail dispatcher in Toronto. The front part of the train, which had the other copy of the manifest, arrived in Cooksville, about six kilometres from the derailment. At 1:30 a.m., a readable copy of the manifest was delivered to a makeshift command post, which has been established shortly after the derailment in a building just south of the fire.

Peel Regional Police and other emergency services established on-site emergency command posts just south of the site. Peel Police Chief Burrows and his Deputy Chief William Teggart assumed control of the police command centre. Members of neighboring police forces, fire departments and ambulance services had been alerted or volunteered services.

After obtaining the manifest, senior officials gathered for a meeting to evaluate the situation. This meeting involved the police chief, Deputy Fire Chief Arthur Warner, Chief Fire Inspector Cyril Hare, various CP Rail officials, two officials from the Ontario Ministry of the Environment and some local chemical experts. On checking the serial numbers of the derailed cars with the manifest, some worst fears were confirmed. The derailed cars were carrying a mixed cargo of dangerous chemicals. In the command post, officials discussed the possible chlorine gas threat. Chlorine, a deadly chemical, forms a greenish-yellow cloud when released and is so heavy that it often hovers close to the ground. Since its mass weight is roughly 2.5 times that of air, a cloud of chlorine will slump following the terrain as it drifts and disperses. This feature led to its use as a weapon in the First World War at Ypres, Belgium, where thousands of Canadian soldiers were killed as a result of the gas release. Once chlorine gas is breathed, it saps the fluids in the linings of lungs and blood and starts a chain reaction that ends with slow suffocation.

At the site, it was quickly deduced that the chlorine tanker was indeed close to a filled propane tanker in continuing danger of exploding. After consulting with Fire Chief Bentley, the police chief made the first tough decision of the long week. He ordered 3,500 residents living closest to the derailment to leave the area for their own safety. With the yellow and red fire background, police officers using loud hailers or knocking on doors alerted sleepy residents of the evacuation notice. This evacuation – the first of 13 in a 20-hour period – began about two hours after the car went off the tracks.

Later, as winds shifted and more information about the fire and the train’s cargo became known, areas of evacuation were widened. Shortly after 2 a.m., Metropolitan Toronto Police sent sound trucks to assist in telling residents of the evacuation. Police arranged for the selection and establishment of evacuation centres for those who could not stay with friends and relatives outside the area. The Mississauga section of the Canadian Red Cross Society began organizing for registering and feeding evacuated residents at reception centres. Square One, a huge covered shopping centre 2.4 kilometres northeast of the derailment, was selected as the first centre.

Other preparations started. The provincial Ambulance Co-ordinating Centre sent a general call for ambulances in the surrounding area. One hundred and thirty-nine ambulances and 300 ambulance workers arrived in the area within six hours of the accident from as far south as Niagara Falls (130 km) and as far east as Kingston (275 km). Twenty-seven other vehicles were also provided, including buses from the Toronto Transit Commission, Oakville Transit and Mississauga Transit.

Throughout the night and early morning as machinery arrived and plans developed, experts to handle the dangerous substances also entered the scene. Experts from chlorine emergency plan, (CHLOREP), arrived armed with their equipment headed by Stu Greenwood and his team from Dow Chemical Co. in Sarnia, owners of the chlorine in the tanker. Experts agreed that it would be impossible to seal the chlorine tanker leak until the propane fires had burnt themselves out.

Firefighters continued to increase the spray of water, and more water lines were added. Eventually 10 master streams were applied through about 4,000 metres of hose. After an hour at the scene, it was decided that firefighters would cool the cars and not extinguish the flames. This would allow a controlled burn of escaping gases and avoid possible explosions.

Shortly after another area was ordered evacuated, Chief Burrows moved the police command post because of a shift in winds. The mobile communications trailer of the Ontario Provincial Police joined other trailers at the new command centre in a Bell Canada building less than a kilometre north of the derailment.

Just before 5 a.m., officials at the scene decided that the seriousness of the situation was not diminishing and that provincial officials, including Solicitor General Roy McMurtry should be notified. Under provincial government guidelines on such emergencies, the solicitor general was the provincial official in charge as chairman of emergency planning committee of the Ontario Cabinet. Other local officials such as Frank Bean, Chairman of Peel Region Council, and Mississauga city councillors, Peel Region’s social services department and Mississauga city employees were also alerted.

As dawn broke on a dull cool day, the first four members of “think tank” group, the decision-making committee, which would operate during the next six days, met at 7:30 a.m. It included Bean, Mayor McCallion, Chief Burrows and Fire Chief Bentley.

About an hour later, Chief Burrows issued another evacuation notice. But the later decision to evacuate Mississauga General Hospital and two adjacent nursing homes would be most dramatic and tense.

With the arrival of Solicitor General Roy McMurtry and Deputy Minister John Hilton, further meetings were held and the evacuated areas were increased as the threat to public health and safety became apparent. By 1:30 p.m., the boundaries were further extended south to Lake Ontario and Square One, the first evacuation centre, was closed although it was just north of the evacuated border. Evacuees were transferred to other centres.

As winds shifted, new dangers were presented, forcing more and more residents to join the exodus – some with packed luggage and others with Sunday dinner abandoned on the stove.

At the day’s end, about 218,000 persons had left their homes, six nursing homes, and three hospitals including Oakville-Trafalgar Hospital, just outside the western border, and Queenway Hospital, just beyond the eastern boundary.

The southern part of Mississauga, Canada’s ninth largest city with a population of 284,000 was a virtual ghost town.

Monday November 12, 1979
It truly was a closed city. Commuter traffic to Toronto was rerouted around the evacuated area, causing massive traffic jams for the rest of the week. The Queen Elizabeth Way, the busiest stretch of highway in Canada, which runs through the central part of the Mississauga core, was closed at its eastern and western entrances to Mississauga.

Officials feared that a propane tanker might explode during the rush hours or that chlorine might waft over the highway, trapping thousands of commuters in their cars.

By 10 a.m., three or four propane cars continued to burn but these fires were under control. Firefighters were sticking to the strategy of permitting the fires to burn themselves out. Because of various explosive vapor-producing substances, firefighters were ordered only to confine and control the flames.

Meanwhile, Procor Ltd., of nearby Oakville, a major manufacturer of railway tank cars, prepared a steel patch to cover a one-metre hole in the tanker. Photographs revealed the hole, and it was surmised that at least some chlorine had escaped. But at this point, it was not known how much remained in the tank. The task then involved attempts to find out how much chlorine was left in the tanker and to cover the hole to prevent more leakage.

During the day, railway crews removed box cars and tankers, which had not been derailed, attempting to clear as much debris as possible without disturbing the chlorine tanker and propane tankers piled around. Chemical experts worked to devise ways of eliminating the chlorine threat while staff of the Ontario Ministries of the Environment and Labour were constantly monitoring air in the area. Most samples showed no hazard for healthy adults but a few pockets of chlorine gas had collected in low-lying areas near the site. However, there were enough chemicals in the air to cause discomfort over a significant area.

In reception centres, volunteer groups, Red Cross and St. John Ambulance, supervised the settling of displaced residents and overall co-ordination of food and health services. Meanwhile, police patrolled deserted streets and checked all vehicles entering the area for possible stolen property. Officials could not consider lifting the evacuation until the fire was out and the chlorine danger had ended

Tuesday November 13, 1979
A sigh of relief was breathed by anxious experts and officials when the propane flame finally went out at 2:30 a.m. Most firefighting equipment was removed from the site. The all-out effort was now concentrated on patching the tanker.

In late morning, patients were being returned to Queenway Hospital and Oakville-Trafalgar Hospital, which were just outside the fringes of the evacuated areas, but were closed as a precaution.

In early afternoon, the command post committee set new boundaries, after air sampling tests indicated the situation was stable in those areas. At 3:30 p.m., Solicitor General McMurtry announced new borders on the eastern and western boundaries. Five hours later, a further eastern section was opened. The two announcements meant 144,000 persons returned home. However, the rest of the evacuees, living closer to the derailment and in the path of the prevailing winds carrying the deadly gas, would have to wait.

Patients from the Extendicare nursing home in Oakville and the Sheridan Villa nursing home were also returned to their residences.

At the site, workers had been hampered in completely sealing the tanker by another tanker blocking access to it. As a result of an incomplete seal, a small amount of chlorine continued to escape. However, crews registered success in being able to drain the contents of one propane tanker at dawn. It was later hauled away. Meanwhile at the command post, officials were worried that there was a chance that a propane tanker, which has caught fire, might flare up again.

Wednesday November 14, 1979
Weary workmen struggled to seal the chlorine tanker and decided to take a calculated risk. In trying to lift and drain another half-empty propane tanker before tackling the chlorine tanker, they gambled that the propane would not explode and further tear open the chlorine tanker.

To complicate matters, firemen and command post officials were concerned when a large white cloud of chlorine vapor and water vapor wafted from the derailment site. Pockets of chlorine gas monitored in the deserted area still presented a health hazard for infants, the elderly and anyone with respiratory problems.

During the day, resentment and frustration grew among some evacuated residents, who wanted to return to their homes. The 25-square-kilometre area remained closed, including the two entrances to the Queen Elizabeth Way through Mississauga.

In an effort to alleviate some bitterness, CP Rail offered to pay for hotel rooms for about 1,000 displaced residents, thus relieving the reception areas of some strain and tension.

Thursday November 15, 1979
As crews worked throughout the night and early morning to patch the leak, an estimated 20 to 30 kilos of chlorine were escaping each hour. The steel patch could not be fitted tightly over the rupture. It was supplemented by a neoprene air bag pressed over the opening by a timber mat and secured by chains.

This virtually sealed the tanker, and officials could announce that there was little leakage. Between 7? and 10 tons of liquid chlorine remained in the tank since most of 90 tons of chlorine had apparently been sucked up into Sunday’s giant flames, and the resulting chlorine gas had been dispersed harmlessly over Lake Ontario. Technical experts explained to the “think tank” meeting that a slushy ice mixture of chlorine and water had built up inside the tanker from water poured in by fire hoses. The mixture formed a layer over the liquid chlorine, complicating the removal of any remaining chlorine and delaying this phase of the operation. Scientists worried that this layer of ice might break up and fall into the liquid chlorine, exposing it to the air. However, it was decided that pumping would not start until favorable winds prevailed. The pumping started at 11 p.m.

Earlier in the day, Solicitor General McMurtry announced on behalf of the command team that the remaining 72,000 could not return that night. The end would depend on the removal of the chlorine.

Friday November 16, 1979
Generally, the transfer proceeded smoothly. As a precautionary measure against the spread of small amounts of chlorine emitting from the tank after the patch was fitted, firefighters set up monitors in a fog mode downwind from the chlorine tank to ensure that any remaining chlorine in the air would be captured by water and drawn to the ground.

The problem involving the layer of ice was resolved by applying a liquid line below the ice and a vacuum line above it. X-rays were taken to measure the levels of the tank car and truck during the pumping operation. By noon, most of the chlorine had been pumped into trucks and shipped safely away.

Throughout the pumping, air monitoring continued. Their tests showed no dangerous pockets of chlorine. By 3 p.m., 37,000 persons of the remaining 72,000 were permitted to return home. But the 35,000 residents living closest to the derailment and the first to evacuate, waited another four hours. Finally the boundaries were lifted.

While CP Rail under the supervision of the Canadian Transport Commission, a federal government agency, removed wreckage, the chlorine tanker was not disturbed until the liquid chlorine has been removed and the empty car purged.

At 7:45 p.m., the city was reopened. Police removed road blocks. Only the derailment site remained out of bounds. By late evening, the last reception centre was closed and by midnight, Metro Toronto police, the provincial police and RCMP had finished their duties.

On Monday, November 19, the chlorine tank was finally emptied and the clearing of the tanker started.

On Tuesday, November 20, the last ambulance on standby was dismissed.

On Wednesday, November 21, the last piece of fire equipment was removed.