Unifor is mourning the loss of life at the Suncor worksite on Wednesday. A Unifor Local 707A member was mauled by a bear on the job.
"Unifor offers our deepest condolences to our member's family," said Unifor National President Jerry Dias.
The name of the oilsands worker is not being released at this point.
Alberta Occupational Health and Safety will be investigating.
"We will do everything we can to contribute to the investigation," said Angela Adams, Unifor local 707A treasurer.
"It's our goal to make all workplaces as safe as possible," Dias said.
Unifor represents 3,000 workers at Suncor in Fort McMurray. Unifor was formed Labour Day weekend 2013 when the Canadian Auto Workers and the Communications, Energy and Paperworkers unions merged.