When Was The Mississauga Train Derailment

when was the mississauga train derailment


Mississauga, Ontario, is a city rich in history and cultural significance, shaped by impactful events and developments. One of the significant incidents that marked a turning point in the city's history and evolution is the infamous Mississauga Train Derailment.

The Mississauga Train Derailment: A Look at the Date and Background

The Mississauga Train Derailment, also known as the Mississauga Miracle, occurred on November 10, 1979. The train, a 106-car CP Rail freight, was en route from Winnipeg to Toronto carrying a variety of commercial goods and dangerous commodities, including propane and chlorine.

A Closer Examination of the Train Derailment

Late into the night of November 10, a hot box, an overheated journal or wheel bearing, caused wheels on the 33rd car to lock and the following 24 cars to derail. In the chaos that ensued, several tank cars filled with explosive and toxic substances ruptured and caught fire, causing massive explosions and a cloud of lethal chlorine gas to linger over the area.

The Evacuation and Its Significance

The catastrophe led to the largest peacetime evacuation in North American history at that time, with approximately 240,000 residents temporarily displaced from their homes. Despite the potential for massive disaster, there were no fatalities or serious injuries, greatly due to the swift and decisive action taken by local authorities and emergency services.

The Impact on Mississauga and Beyond

Although the immediate danger was averted, the derailment had far-reaching implications for Mississauga and all of Canada. The event led to significant changes in railway safety regulations and guidelines, demanding stricter safety procedures for the transport of hazardous materials. For Mississauga, it was an event that tested the city's emergency response capabilities and ultimately, led to the strengthening of its procedures and infrastructure in disaster management.


The Mississauga Train Derailment of 1979 was a monumental episode in the city’s history. Its effects extended far beyond the displacement of its citizens, shaping how the city and the country handle and regulate the transportation of hazardous goods. It highlighted the importance of efficient and effective emergency responses in the wake of large-scale disasters. Despite the chaos it caused at the time, it evolved to become a catalyst for improvement in safety standards across the board, rightfully earning its place as a significant moment in Canadian history.