In the end it was impossible for the coronial court to say what caused the fatal failure of bolts holding the concrete boom as it swung over the heads of workers.
When the boom fell that morning, shortly after being serviced, it killed a young man named Ben Catanzariti, three weeks into the job and only 21 years old.
"It's been six years, six months and 25 days since the preventable death of our son Ben, 21 years old," his mother Kay Catanzariti said on Friday, her voice competing with jack hammers from a nearby work site.
"Ben just went to work and was killed on the 21st July 2012."
"It's a human right to go to work and come home alive. It's not a war zone, it's not a death sentence."
On Friday, findings in a long awaited inquest into the man's death were handed down in the ACT Coroner's Court.
The coroner said it was not possible on the evidence to say what caused the bolts on the boom that day to fail.
It was a similar conclusion reached by prosecutors years earlier, who abandoned a criminal prosecution of the company in the face of multiple reports suggesting various reasons for why the boom failed.
The inquest heard how witnesses reported hearing a loud crack before the concrete pouring boom that had been sweeping across the site fell hard and fast toward scattering the people in hi vis.
The boom hit three workers. It struck Mr Catanzariti on the back of the head and fractured his skull, killing him at the Kingston site.
It emerged that there were fatal weaknesses in the bolts securing the boom to the machine.
But what caused the bolts to fail was an ongoing controversy, and one left unsolved.
Experts had provided multiple different opinions in separate reports, some commissioned by various parties.
And in the end, the ACT Coroner's Court found it was impossible on the evidence to determine the operative cause of the bolts' failure.
Coroner Karen Fryar also said it wasn't possible to attribute any blame.
The coroner was left to use a broad brush in her recommendations and address each possible cause.
Assuming it was the failure of employees at Schwing Australia, which had serviced the boom before the death, Ms Fryar recommended the company review its processes as to installation of bolts.
The company should also review the methods they use to ensure bolts are uniformly tensioned, and to ensure load testing is carried out.
Lawyers for the company had informed the coroner those reviews had already taken place.
Assuming the boom collapsed because the bolts themselves failed from a weakening process known as hydrogen embrittlement, the coroner recommended WorkSafe ACT refer the reports to the manufacturers and suppliers for their consideration as to whether the bolts or any zinc coating met relevant industry standards.
And assuming that the failure was a combination of these factors, Ms Fryar recommended Worksafe ACT refer the reports to Safe Work Australia, for consideration about the need for Australian-wide standards.
Ms Fryar said she hoped was that Mr Catanzariti's death had been the trigger for reform, so that construction sites within the ACT and around Australia might be safer workplaces.
Ms Catanzariti has been campaigning tirelessly since her son's death, imploring the government to improve safety on work sites.
But for all her efforts, no-one has been held accountable.
"There's no accountability in justice," she said. "And it's not an equal playing field.
"Why have I had to fight so hard for this? It's not my job, it's the government's.
"You're broken in every way possible, mentally, physically, and emotionally.
"Your health deteriorates, it becomes a terminal illness."
She thanked the Construction, Forestry, Mining and Education Union, which had supported her through the process, and former secretary Dean Hall, who she said had saved her life.
She also said she wanted to see the law change to put a workable industrial manslaughter crime on the books.
In a statement, ACT Minister for Workplace Safety Rachel Stephen-Smith said the government was committed to doing all it can to ensure workers return safely to their homes and families.
She said that since 2012 there had been a number of measures put in place to improve workplace health and safety, and the government had recently reviewed compliance and enforcement arrangements.
Ms Stephen-Smith said the government continued to advocate for industrial manslaughter to be included in the model work, health and safety laws.