Two workers walked off the job over safety concerns before a fatal accident at a Brisbane construction site, the CFMEU has revealed.

A big concrete slab crushed two men to deathwhile they were working on a major redevelopment of the stables at the Eagle Farm Racecourse on Thursday.

The union’s workplace health and safety coordinator, Andrew Ramsay, said one worker came forward yesterday and another this morning.

“I received a call from another person who worked on the job,” he said.

“He thought someone was going to die there … so he walked off the job.

“He actually said: ‘It’s the first time in my working career that I have walked off a project’.”

Ashley Morris, 34, and his 55-year-old workmate, were killed when two 9-tonne concrete slabs fell down in a pit they were standing in.

The union said the slabs may have been poorly braced inside the pit.

“The other panel that came down on top of them sandwiched them in between the two panels,” Mr Ramsay said.

“They wouldn’t have had a hope in hell, the poor buggers.”

Construction company Criscon could not be reached for comment.

The mother of Mr Morris, who has two young children of his own, laid flowers down at the gates of Eagle Farm Racecourse in memory of her son.

The union will meet with the family on Monday to discuss their entitlements and help in their fight for answers, to find out how the accident happened.

The Brisbane Racing Club has stopped construction at the Eagle Farm redevelopment.

Jockeys raced at nearby Doomben racecourse wearing black armbands to pay their respects.

The racing manager from the Brisbane Racing Club, Bart Sinclair, said Thursday was one of the saddest days in the club’s 150-year history.

“It’s a way of the stakeholders saying how much they sympathise with the families of the two unfortunate gentlemen,” Mr Sinclair said.

Industrial Relations Minister Grace Grace has ordered Workplace Health and Safety to deliver a full report on the incident as soon as possible.

-ABC