By Nia Williams and Scott Haggett
CALGARY, Alberta, June 27 - Five rail cars carrying hazardous petroleum products derailed on a broken bridge over the swollen Bow River in Calgary, Alberta, on Thursday, 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. CP blamed increased flows on the river for scouring away one of the bridge's supporting piers.
The Bow, one of two rivers flowing through Calgary, Canada's oil capital, reached record levels in devastating weekend floods that swamped many neighborhoods and likely caused billions of dollars worth of damage. The river is still flowing at three times the normal rate.
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."
Mark Seland, general manager of communications and public affairs for Canadian Pacific, said the bridge had been inspected 18 times since the flooding started in Calgary but the company had not inspected the underwater piers.
CP Chief Executive Hunter Harrison told the Globe and Mail newspaper there was no way of inspecting below water.
"We couldn't have seen anything from an inspection on top unless there was severe movement as a result of the failure down below. So we would have normally probably put divers in to inspect, but the current was too fast," Harrison said.
CP said information was not readily available on how many trains have crossed the bridge since it reopened, how much they weighed, or how fast they were traveling.
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 6,000 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 on Thursday. "I have a lot of questions and not a lot of answers."
Seland said CP had not laid off any bridge inspectors in the last year.
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-earlier 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.
The Transportation Safety Board of Canada said it was on site conducting an investigation into the cause of the accident.
"Should any deficiencies be identified, we will not hesitate to take appropriate action," spokeswoman Karine Martel said.