Between 200 and 300 workers at the Irving-owned Halifax Shipyard walked off the job this morning, complaining of bullying by management.

The workers said they're upset by the death of a co-worker. Protesters said the worker, who had about 30 years of experience at the company, was recently suspended over a dispute about scaffolding safety.

He killed himself on Wednesday, CBC News has learned.

Ken Clark, who worked with the man for years, said it started over a trivial matter. The worker was in charge of building staging.

"It was the way he tapped in a lock on a piece of staging," said Clarke. "He used a metal wedge to do it instead of a hammer, that's all it started over."

Clarke said the man's work was witnessed by a supervisor who wrote him up. Several workers told CBC News that incident sparked nearly two months of threats of job ramifications from management. This week, the man was suspended for 30 days.

"They said he built unsafe staging," said Stan Chaulk, who has worked as a rigger for 44 years. "He didn't. We had an engineer brought in … and the staging was perfect."

Chaulk said he was sick to his stomach after hearing of his friend's death.

"He built staging for 38 years. He was up there from ship one. There was no problem."

"He was just trying to keep the boys safe," said Derrell Provo, a metal fabricator.

Irving Shipbuilding issued a statement Thursday afternoon.

"The Irving Shipbuilding family was devastated by the news of the death of Peter MacKenzie," Irving Shipbuilding wrote in a statement. "Our thoughts and hearts go out to Peter's family and friends, and to all here at the shipyard who worked with him."

But the company wouldn't discuss the allegations from the workers but said they had "no basis in fact."

"It is not appropriate to speak about details regarding individual employees — our objective here is to respect family and friends and the employee's memory," the statement said.

A second email to CBC News addressed the allegations of conflict over safety.

"We encourage employees to voice their concerns regarding safety and in fact, they are incentivized for doing so," wrote Deborah Page, a spokesperson for Irving Shipbuilding. "Our highest priority is the safety of our workforce and our actions are consistent with this commitment."

She said the company is working hard to create a positive, effective environment.

"For that, we need employees to be at work, and the union and company to work together."

The workers left the Halifax Shipyard just before 9 a.m. AT on Thursday and made their way down Barrington Street in downtown Halifax, blocking traffic in both directions.

"We're heartbroken … the boys are not going to put up with it anymore. This is absolutely intolerable," Bob Couture, a pipe fitter, told CBC's Maritime Noon.

"We'll never forget our brother."

Flags at the yard are flying at half-mast.

The union met with management on Thursday morning to try to get the workers back on the job.

Couture said the employees feel like management is trying to push out older workers.

"They have been firing boys left right and centre because of fights," he said.

"We're talking bullying, continuous bullying … when they’re not doing anything wrong and there’s a vendetta against them that’s not right.”

Other workers said the atmosphere at the shipyard has changed dramatically after new managers were hired.

"They're worried about what glasses you've got on, or what hat," said Chaulk. "They don't care about what work you can do … it's time for this bullying to stop."

Chaulk said he's seen some of the employees "tortured" by the treatment.

"It had to take a man's life to come this far."

"It shouldn't have had to come to that, for us to do this," said Darcy Baker-Mosher. "Everyone wants to work. We're excited for 30 years."