Ed Greenberg of Canadian Pacific Railway confirmed the product — used to dilute raw oilsands bitumen _ did not leak into the river.
He said crews are now preparing to remove the derailed units by stabilizing them while locomotives positioned on each side of the damaged bridge will pull the cars safely to each side.
Greenberg said that should be completed by Friday morning.
Earlier in the day, Mayor Naheed Nenshi chastized Canadian Pacific for the derailment, which happened in the wee hours Thursday morning.
But later he said the rail company had apologized for the chaos, which added to tensions in the flood-ravaged city.
"How is it we don't have regulatory authority over this, but it's my guys down there risking their lives to fix it?" Nenshi asked early in the day.
"Certainly once this crisis is over, I'll be looking for a lot of answers from a lot of people."
Railways are under federal jurisdiction and are responsible for their own inspections.
By late afternoon, after a conversation with CP (TSX:CP) CEO Hunter Harrison, the mayor softened his stance.
"He extended an apology to the citizens of Calgary for what has happened here," Nenshi said. "We both agreed, No. 1, our primary responsibility is to get this thing cleaned up and, No. 2, that we will work together much more and he reiterated safety in every community CP Rail runs through is a primary responsibility."
CP said the bridge had been inspected on Saturday and the tracks on Monday. However, Harrison later told reporters the bridge was inspected five times after floodwaters rose. And CP engineers at the scene said the bridge had actually been inspected 18 times since flooding began.
Harrison said it was "clearly" a failure of piers at the bottom of the river. The engineers blamed it on fast water scouring away gravel under the support.
"We couldn't have seen anything from an inspection on top unless there was severe movement as a result of the failure down below," Harrison said. "We would normally have probably put divers in to inspect, but the current was too fast. Somebody would have drowned if they had tried to go in there, plus the current was so fast, and it's so murky, you couldn't do an appropriate inspection."
The rail company didn't anticipate "a problem like this occurring at all," said Harrison, who said it would have been "jeopardizing commerce" to hold back trains until divers could get in.
He also said the bridge's failure was as "extraordinary" as the heavy rains and flooding in southern Alberta. The bridge was built in 1912 and hasn't had a failure like this since 1944, he noted.
Nenshi wondered if recent layoffs at CP had anything to do with the situation.
"I'll be very blunt. I'll probably get in trouble for saying this," Nenshi said. "We've seen a lot of people lose their jobs at CP over the last year. How many bridge inspectors did they fire?"
The company, however, said the number of bridge inspectors remained the same.
Federal NDP transport critic Olivia Chow said the federal government has to stop allowing rail companies to conduct their own inspections.
"They can do their own inspections, but the federal government — or some level of government — need to inspect bridges," she said.
"Mayor Nenshi is absolutely correct. He was being very polite, but it's the municipal government's personnel whose lives are on the line and yet they have absolutely no say whether these bridges are safe or not."
In 2008, two separate advisory panels made 70 rail safety recommendations. A House of Commons standing committee expressed serious reservations about the so-called Safety Management System, under which much of the responsibility for safety was devolved to rail companies.
The committee made several recommendations to modify the system and legislation was eventually passed.
But Chow said not enough has been done.
"There are fewer inspectors today than there were a few years ago."
Chow said $3 million was cut from rail safety in the most recent budget, which followed a $500,000 cut the previous year.
In an emailed statement, Transport Minister Denis Lebel said the department is responding.
"The Transportation Safety Board of Canada is onsite to conduct a full investigation to determine the cause of the accident," he said. "A Transport Canada ministerial observer will be present to report back on the investigation’s progress.
"Transport Canada is increasing oversight in southern Alberta as a prudent and precautionary measure."
Transportation Safety Board investigator James Carmichael said CP will be asked about its protocol for inspecting lines after floods.
"All the bridges, track, railcars, locomotives — they all are required by Transport Canada to be inspected regularly and I don't have all the time frames on all the stuff with me at the moment," he said. "We are going to gather all the records from all the inspections that have recently taken place.
"We're here to find out what happened and why and how to prevent it from happening again — or at least mitigating any circumstances where it could happen again."
Alberta Transportation Minister Ric McIver said discussions around rail jurisdiction and CP inspections were for another day.
"I feel very confident that the infrastructure that we have in place is, generally speaking, in very good shape," he said.
Also on HuffPost