By Samantha Craggs, CBC News Posted: Aug 05, 2014 4:47 PM ET Last Updated: Aug 05, 2014 4:47 PM ET

The Ontario Labour Relations Board is investigating a contract offer between McMaster University and its cleaners that would see the service privatized if the union doesn’t accept the university’s offer.

About 260 support staff voted on a new contract Tuesday. Two-thirds of them are custodians and casual cleaners, the lowest-paid staff at the university.

If the group doesn’t accept this final offer, McMaster says, it will permanently privatize its cleaning services.

But the board ordered the ballot boxes sealed Tuesday morning as it investigates the lawfulness of McMaster’s offer. The Building Union of Canada (BUC) asked for the investigation on Friday.

It’s a rare move for an investigation to be granted, said president Craig Bromell, a former head of the Toronto Police Association who founded the BUC in 2012.

“We’re trying to make heads or tails of it.”

Union kept ‘widening the gap’

Bromell hasn’t heard how long the investigation will take, only that “further information will follow.”

It’s the latest turn in a dramatic eight months of bargaining between BUC and McMaster. The Service Employees International Union represented the group for 40 years. But the employees switched to the BUC last November, triggering a new round of collective bargaining.

Both sides say the goal is to get the lowest-paid workers, most of them women, to a living wage of $14.95. McMaster’s final offer would see the lowest wages increased to $15 per hour by October 2015, spokesperson Gord Arbeau said. It also offers a $750 lump sum payment to every employee.

The university offered to reach a living wage sooner in an earlier round of bargaining, but the other side declined it, Arbeau said.

“During negotiations, the gap was widening rather than narrowing.”

‘Literally living in poverty’

Bromell said the increase should be immediate given that the workers have received an increase of only nine cents per hour for the past four years.

“One-third of this group has not had living wage,” he said. “They’re literally living in poverty. A lot of them are single mothers.”

“The irony of this whole thing, which we think is pretty disgusting, is that they teach poverty courses there, but they won’t even give it to the employees who have the dirtiest jobs.”

About 74 faculty, staff and officials from other unions signed a letter on Aug. 1 to “express deep concern and strong disagreement” with the university’s ultimatum. Tina Fetner, an associate professor of sociology, drafted the letter.

“To force some of the most vulnerable members of our community to choose between a living wage and retaining their jobs is an unacceptable tactic,” the letter says.

Workers face ‘a grim choice’

The cleaning staff face a grim choice, Fetner said.

“I have a lot of sympathy for the workers voting between a sub-standard poverty wage and the threat of being outsourced. With their choices today, that’s what they’re looking at.”

McMaster has posted the agreement to its website in the interest of transparency, Arbeau said. If the final offer falls through, he said, it’s the university’s “responsibility to students” to privatize the service.

“We can’t have uncertainty as the academic year draws nearer,” he said. “We have a responsibility to those coming back to the university.”

McMaster is confident the ministry will find its offer lawful, he said.

“It’s a fair and reasonable one that addresses concerns about living wage and also ensures pay increases and improved shift premiums.”