1979 Mississauga train derailment

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The Mississauga train derailment of 1979 occurred on November 10, 1979, in Canada, when a 106-car Canadian Pacific freight train carrying dangerous chemicals from Windsor to Toronto was derailed near the intersection of Mavis Road and Dundas Street in Mississauga, Ontario, spilling its cargo, which exploded and sent a gas cloud into the air. As a result, over 200,000 people were evacuated in what was the largest peacetime evacuation in North American history until the New Orleans evacuation of 2005. Remarkably, there were no deaths resulting from the incident.

1 Causes
2 Explosion
3 Evacuation
4 Aftermath
5 Legacy
6 See also
7 References

[edit] Causes

The train was heading west towards Mississauga. As it was travelling through the Milton area, heat began to build up in an improperly-lubricated journal bearing on one of the wheels of the 33rd car, resulting in the condition known among train workers as a hot box. Residents living beside the tracks reported smoke and sparks coming from the car, and as the train entered Mississauga many thought that it was on fire. The friction eventually burned through the axle and bearing, and at 11:50 p.m. as the train was passing the Burnhamthorpe Road level crossing, one axle and a pair of wheels fell completely off, landing in the backyard of a house 15 metres from the track. 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.

[edit] Explosion

At 11:53 p.m., the dangling undercarriage left the track. 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.

As the derailed train's tank cars became twisted and tangled, tankers containing styrene, toluene, propane, caustic soda, and chlorine were punctured, spilling their contents onto the track beds and into the air. This caused a massive explosion within a minute, which sent a fireball 1,500 m into the sky that could be seen from 100 km away.

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 that more help was urgently needed.

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. Along a kilometre stretch, windows were shattered, three greenhouses destroyed, as well as a municipal recreational building. A green haze began drifting into the air.

Two more explosions occurred within 15 minutes. Both were "BLEVES" (boiling liquid expanding vapour explosions) that occurred in propane tanks. The first hurled a car into the air, which tumbled across a field before coming to rest 675 metres northeast of the Mavis Road crossing. The second sliced a car in half, with one half travelling about 65 metres.

As machinery arrived and plans developed, experts from Chlorine Emergency Plan, (CHLOREP), arrived armed with their equipment headed by Stu Greenwood and his team from Dow Chemical Company in Sarnia, the owners of the chlorine in the tanker. Together, they 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, eventually to 10 master streams through about 4,000 metres of hose. After an hour at the scene, it was decided that they would cool the cars and not extinguish the flames to allow a controlled burn of escaping gases and avoid possible further explosions.

[edit] Evacuation

By now, CP Rail dispatchers' offices in London and in Agincourt, the ultimate destination of train 54, were notified of the derailment through CP's radio system. Peel Regional Police and other emergency services established on-site emergency command posts just south of the site, and members of neighbouring police forces, fire departments and ambulance services had been alerted or volunteered services.

After obtaining the train's manifest, senior officials gathered for a meeting to evaluate the situation. Upon checking the serial numbers of the derailed cars, some worst fears were confirmed. The train was carrying a mixed cargo that included dangerous and explosive chemicals. Officials discussed the possible chlorine gas threat. At the site, it was quickly deduced that the chlorine tanker was close to a filled propane tanker that was still in danger of exploding. After consulting with the Fire chief, Police chief Burrows ordered 3,500 residents living closest to the derailment to leave the area for their own safety. 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 derailment.

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 chapter of the Canadian Red Cross began organizing for registering and feeding evacuated residents at reception centres. Square One 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.

Shortly after, another area was ordered evacuated, and the police command centre was moved to a Bell Canada building within a kilometre away because of a shift in winds. At about 8:30 am, another evacuation notice was issued, and later on, Mississauga General Hospital and two adjacent nursing homes were evacuated.

The evacuated areas were further increased as the threat to public health and safety became apparent. By 1:30 p.m., the boundaries were 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.

A considerable number of residents who were not evacuated (mostly the extreme west and north of Mississauga) allowed evacuated residents to stay with them until the crisis abated. Some of these evacuees were later evacuated twice as their hosts were later evacuated also. The evacuation was overseen by the mayor of Mississauga, Hazel McCallion, along with the Peel Regional Police and other governmental authorities. McCallion sprained her ankle early in the crisis, but continued to hobble to press conferences and updates.

[edit] Aftermath

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

Mississauga, then Canada's ninth largest city with a population of 284,000 was a virtual ghost town. Commuter traffic to Toronto was rerouted around the evacuated area, causing massive traffic jams for the rest of the week. The Queen Elizabeth Way, which runs through the central part of south Mississauga, was closed at its eastern and western entrances to the city because 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 November 12, the fires were mostly under control. 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.

The propane flame finally went out at 2:30 a.m. on November 13, and most of the firefighting equipment was removed from the site. The all-out effort was now concentrated on patching the tanker. In the late morning, patients were being returned to Queensway Hospital and Oakville-Trafalgar Hospital, which were just outside the fringes of the evacuated areas, but were closed as a precaution. In the 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., new borders were announced 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. There was concern over the chance that a propane tanker, which had recently caught fire, might flare up again.

By the next day, pockets of chlorine gas monitored in the deserted area still presented a health hazard for infants, the elderly and anyone with respiratory problems. In addition, resentment and frustration grew among some evacuated residents, who wanted to return to their homes. 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.

Between 20 and 30 kilos of chlorine had been leaking from one of the tankers every hour. However, when the leak was patched, between 7 and 10 tons of liquid chlorine remained in the tank since most of 90 tons of chlorine had apparently been sucked up in the explosion's giant flames, and the resulting chlorine gas had been dispersed harmlessly over Lake Ontario.

On November 16, the remaining chlorine was being pumped into trucks, and by noon, most of it had been shipped safely away. Throughout the pumping, air monitoring continued. Tests showed that there was no longer any 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 until the boundaries were finally 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. The chlorine tank was emptied on November 19, and in the next two days, the final ambulance on standby and the last piece of fire equipment were removed.

[edit] Legacy

At the time, it was the largest peacetime evacuation in North American history, and is currently the second largest behind the evacuation of New Orleans, Louisiana after the impact of Hurricane Katrina.

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 inquiry.

Due to the speed and efficiency with which it was conducted, many cities later studied and modelled their own emergency plans after Mississauga's.^{[citation needed]} For years afterwards, the name "Mississauga" was for many Canadians associated with this major rail disaster.

The crash happened in an industrial area which remains mostly industrial today, although the area immediately to the east has since been redeveloped.