Support staff at Carleton University have taken to the picket lines after a last-ditch round of bargaining Sunday failed to yield an agreement.

Pension benefits have been the main sticking point between some 800 workers and their employer since negotiations began in July 2017, CUPE 2424 president Jerrett Clark told CBC News.

"The employer is proposing to take away bargaining and protections from our collective agreement language that we've had for 40 years," said Clark.

The striking workers include admissions, administration, IT, some librarians, athletics, counselling services and animal care people.

The union says Carleton University wants to scrap protections in the current collective agreement that guarantee workers' defined pension benefits in favour of a defined contribution plan.

We have had this language for 42 years, and they want to remove it so we are no longer bargaining our pensions. - Leslie MacDonald-Hicks, CUPE 2424 negotiating team member

Defined benefit plans offer retirees a steady cheque each month, but they're costlier to maintain as employers must guarantee there's enough money in the plan regardless of current investment returns.

Defined contribution plans, on the other hand, rely on employees investing a set amount each month, with no guarantee of how much they can expect to receive once they retire.

Pensions have been a source of disagreement in the negotiations, according to the union. (Christian Milette/Radio-Canada)

Carleton University president Alastair Summerlee issued a statement last week saying the university has no intention to take away pensions, nor to move toward a defined contribution plan.

But the union isn't buying it.

"What we fear is that what they are proposing will open the door to those kind of changes — the changes that we just can't accept," said Clark.

Clark has said that about 700 workers have signed up for picket duty, with plans to block the Bronson Avenue and Colonel By Drive entrances to the campus starting Monday.

Classes will continue as scheduled in the event of a strike, according to the university.

OC Transpo will not cross picket lines, letting students off instead on Bronson Avenue, the university said.

The O-Train will be running as normal.