The Transportation Safety Board says seven rail cars that derailed in northern British Columbia last Thursday were filled with liquefied petroleum gas.
Board spokesman Alexandre Fournier says in an email that seven of the 28 derailed cars were filled with the gas, which is classed by the federal government as a flammable and dangerous commodity.
Canadian National Railway could not immediately be reached for comment, but last week the company said there was no danger to the public as a result of the derailment.
The local school district says Giscome Elementary was evacuated after the derailment due to uncertainty about the contents of the rail cars.
The school, which is 200 metres from the rail line, remains closed and classes have been moved to a nearby elementary school.
CN has said ``a small amount'' of petroleum coke spilled into a nearby waterway after the train derailed.