Five rail cars carrying hazardous petroleum products derailed on a broken bridge over the swollen Bow River in Calgary, Alberta, today, perching perilously close to the water as emergency crews rushed to prevent a spill.
The cars contain petroleum distillate, a flammable light oil product that is used in paint and polishes or can be mixed with the sludgy crude from the Canadian oil sands so the crude can flow in pipelines.
The tanker cars left the tracks but remained upright and were not leaking, operator Canadian Pacific Railway said.
The Bow, one of two rivers flowing through Calgary, Canada's oil capital, reached record levels in devastating weekend floods that swamped many neighbourhoods and likely caused billions of dollars worth of damage.
The river is still flowing at three times the normal rate, but officials said it was too early to say if the floods were the reason the railway bridge failed.
Part of bridge sank two feet toward the river after the accident, but Calgary Deputy Fire Chief Ken Uzeloc said it had stopped sagging. The Bow River supplies drinking water to many communities and cities downstream of Calgary.
"The first step is secure the remaining rail cars that are there to ensure if the bridge does collapse completely, the cars are not floating down the river," Uzeloc told a news conference.
"We are trying to identify a position downstream where we can set up booms in case we do get any leakage."
Canadian Pacific spokesman Ed Greenberg said the bridge had been inspected by a qualified inspector on Saturday and the tracks had been inspected on Monday, with follow-up inspections scheduled.
He did not say if the inspectors were from CP Rail or from the federal government and he did not respond to questions about when the bridge reopened after the floods, its weight limits, or how many trains had traveled on it since the weekend floods.
The derailed cars were in a train of 102 cars, he said.
CP Rail is in the middle of a major restructuring designed to improve what had been the worst rate of operating efficiency among North America's major railroads.
Under the leadership of industry veteran, Hunter Harrison, CP is eliminating as many as 6000 jobs and reviewing all its operations. The company's latest results showed the best first-quarter performance in its 132-year history.
"We've seen a lot of job losses at CP. How many bridge inspectors did they fire?" Calgary's popular mayor, Naheed Nenshi, asked at a news conference today. "I have a lot of questions and not a lot of answers."
Calgary's emergency services group said it now plans to bring in pipes and other rail cars to offload the petroleum products, and then use a crane to lift the derailed cars off the bridge.
The accident triggered another round of road closures in Calgary, where most of Canada's biggest oil and gas companies are based, and authorities enforced a half mile evacuation zone around the bridge.
Transport in the city of 1.1 million people had barely got back to normal after the floods, which also affected other communities across southern Alberta.
The derailment could fan concerns about the safety of moving crude oil and petroleum products by rail, which is becoming increasingly popular as environmental worries have slowed pipeline development.
Statistics Canada data showed 14,211 tank cars were loaded with fuel oils and crude petroleum in March 2013, a 63 percent increase from the year-ago levels.
City authorities said the rail bridge is under federal jurisdiction and is not a bridge the city of Calgary would have inspected in the aftermath of the floods.
"It's an old bridge, it dates back to the founding of the CP, it's built with old construction techniques, we don't know much about it," Nenshi said. "The City of Calgary bridges are safe."
In Ottawa, the federal transport department said it was checking to see when its officials last examined the bridge.