Critics are calling for a review of Canada's temporary foreign worker program, after two Chinese workers died when a roof collapsed in northern Alberta.
"I heard a big snap, and that was the cable," witness Brett Taylor, a boilmaker apprentice, told CTV Edmonton.
"I looked over and could see the whole entire things just twist and the roof pulled out and slammed right down on top of everybody."
The accident happened on an oilsands construction site about 70 kilometres north of Fort McMurray.
The workers were building a large oil container as part of Canadian Natural Resources Ltd.'s $10.8-billion Horizon project.
The company has since confirmed the two killed workers were Chinese employees, and four others injured in the same incident were also from China.
Horizon is one of the largest construction sites in Canada with 4,000 people, many of them foreign temporary workers.
"We knew that it was just a matter of time before somebody was going to lose their life on that site," said Tim Brower of IBEW Local 424.
Witnesses say there were high winds at the time of the collapse that may have caused the accident.
One witness said it had nothing to do with the workers' nationality or any perceived lack of training.
"I don't think you can blame the foreign workers," he said. "They're just working men. They work hard."
Some labour groups have said Canadian Natural relies too much on foreign workers to help cover a massive labour shortage in northern Alberta.
"Over the last year or so, especially on construction projects in northern Alberta, we've gone from a situation where the program was used as a temporary stop-gap to a one-stop human resources strategy for employers," Gil McGowan, president of the Alberta Federation of Labour, told The Canadian Press.
He added that questions must be asked about how well trained such workers are, and whether the temporary foreign worker program must be overhauled.
"For example, did these workers receive adequate health and safety training before they started working on a Canadian worksite?" he asked. "Were there issues related to language and communication that played a role?
"These are questions that aren't always addressed in ordinary health and safety investigations, but given the nature of this particular workplace accident, we think the investigative authorities need to leave no stone unturned."
Peter Janson, vice-president of engineering and integration, defended the skill and training of the Chinese workers.
"My belief is that they are competent, they meet those requirements or they wouldn't be certified," he said.
A Health and Safety spokeswoman told CP a thorough investigation of the accident means it could take years to write a final report.
With a report by CTV Edmonton's Dan Kobe and files from The Canadian Press
