Just over a year ago, Corina and Joe Colacicco — both employees at the General Motors facility in Oshawa, Ont., — sold their house and bought a bigger one to accommodate their growing family.

Today, the couple is contemplating what might happen to them and their four-year-old son if GM decides to close up shop in the southern Ontario city just east of Toronto.

"We've got all our eggs in one basket," says Joe, whose father spent 30 years working for GM before retiring several years ago. "I grew up on a GM paycheque my whole life, like most of my family has, so it's hard to even fathom the thought that they might not be there one day."

Oshawa is a ground zero of sorts for the ongoing contract negotiations, which kicked off last month, between the Detroit Three automakers and its unionized workers.

A worker at General Motors in Oshawa checks the hood of a car on the assembly line. (Frank Gunn/Canadian Press)

The plant, whose future is on the line, represents the struggle between the union's desire to keep investment in Canada and efforts by the Detroit Three to move production to jurisdictions such as Mexico and the southern U.S., where labour and power costs are lower.

GM's operations in Oshawa include two production lines. The consolidated line, which produces the Chevrolet Equinox, was originally expected to close in 2005 but continues to operate.

It is scheduled to close next year, and if that happens, Joe expects he'll be shown the door.

As a supplemental workforce employee, Joe doesn't enjoy the same pay, benefits or job security that his wife Corina, an employee of 14 years, does. Over the past decade he has been laid off several times before being called back to work.

But even the flex line, which Corina works on, faces an uncertain future.

Jerry Dias, national president of Unifor, says securing new investment in Canadian assembly facilities is the union's top priority. (Ryan Remiorz/Canadian Press)

The flex line produces the Chevrolet Impala, the Buick Regal and the Cadillac XTS, but it has no product scheduled past 2019.

That has given rise to concerns that the automaker could be planning to pull out of Oshawa entirely.

"We could be shut down by 2019 with no jobs whatsoever in Oshawa," says Jeremy Pooler, the strike co-ordinator for Unifor Local 222, which represents workers at the roughly 100-year-old plant.

"I could stand to lose my job."

General Motors employs more than 4,800 people in Oshawa, according to the automaker.

But it isn't just direct GM jobs that would be lost if the company shuts down the plant, Unifor says. The union estimates that more than 20,000 indirect jobs could also be affected — from parts makers that supply the plant to local restaurants and other businesses that cater to GM employees.

Unifor president Jerry Dias has said that securing new investment in Canadian assembly facilities is the union's top priority.

Future of GM hot topic in talks

On Tuesday, the union is expected to announce the company it will target in negotiations and it says any agreement it strikes would serve as a template for talks with the other two automakers, a process known as pattern bargaining.

The future of GM's operations in Oshawa has been a hot topic in the discussions, says Pooler.

"Our main concern every time we go to bargaining is a future for Oshawa -- a product for Oshawa," says Pooler, who has worked at GM for 12 years.

The automaker has said it won't commit to a new product until after a deal has been reached.

That leaves the Oshawa plant, GM's first manufacturing facility in Canada, and its workers in limbo.

"It would be very hard," says Corina, sitting in her living room in Courtice, Ont., while contemplating the possibility of the plant's closure.

"We'd have to go elsewhere, I guess, and look for jobs."

But, she adds, the workers are not about to give up.

"We're in for the fight of our lives."