Employees at pipeline builder TransCanada were informed this week that more job cuts are coming.
Spokesman James Millar says the oil downturn has had a profound impact on the company's customers, so it must do whatever it can to reduce costs.
Millar says about a fifth of senior leadership positions are expected to be cut when layoffs and retirements are taken into account.
It's not clear yet how many jobs below that level may be eliminated, he added.
TransCanada eliminated 185 positions from its major projects division in June, the first phase of a process that's expected to wrap up in November.
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The company has about 6,000 employees.
Earlier this week, U.S. presidential contender Hillary Clinton came out against TransCanada's proposed Keystone XL pipeline, a cross-border oilsands conduit that has been stuck in U.S. regulatory limbo for seven years.