VANCOUVER -- Support for the Trans Mountain pipeline expansion fell significantly after Canadians learned the controversial project's estimated cost had ballooned by more than $5 billion, according to a new poll.

The Angus Reid Institute said the results of its survey represent the first time national support for the Trans Mountain pipeline has fallen below 50 per cent in nearly two years.

Initially, 55 per cent of respondents said they support the project – but after being told the costs have skyrocketed to $12.6 billion, support fell by seven percentage points, down to 48 per cent.

Opposition to the pipeline expansion saw a corresponding increase, from 38 per cent to 45 per cent, after respondents learned about the massive price tag associated with the project.

When the federal government purchased the project from Kinder Morgan, it had an estimated cost of $7.4 billion. With the new estimated cost, British Columbians are more likely to oppose than support the project for the first time in five years, according to Angus Reid's polling.

Some 52 per cent of B.C. respondents said they are against the pipeline, compared to 46 per cent who remain supportive. Support in British Columbia peaked at 61 per cent in June 2018, one month after Justin Trudeau's government purchased the Trans Mountain pipeline, while opposition peaked at 57 per cent in January 2013, about seven months after the project was first announced.

Angus Reid noted the increasing costs have done little to erode enthusiasm in Alberta, where support only fell from 88 per cent to 85 per cent when respondents were informed about the price tag.

The survey was conducted online from Feb. 10-12 using a representative randomized sample of 1,508 Canadian adults who are members of Angus Reid Forum. Polls of that size carry a margin of error of plus or minus 2.5 percentage points, 19 times out of 20.