Former prime minister Kevin Rudd will this week face the royal commission inquiring into his government's botched home insulation scheme, along with several of his former ministers.
They are expected to face a grilling over why the scheme was rushed into operation and whether they ignored safety warnings.
Many public servants have faced a barrage of questions about how the scheme was formulated and if they knew about the risks, especially given that a similar scheme in New Zealand in 2007 had led to the deaths of installers.
So far some of the most controversial evidence presented to the commission revolves around allegations that public servants pressed ahead with the scheme after being alerted to these safety concerns.
But whether such warnings went right up the chain to the prime minister, the then environment minister Peter Garrett or the then parliamentary secretary in charge of the nation-building program, Mark Arbib, before the deaths and whether they acted on them has not been determined.
Allegations have surfaced that Mr Garrett wrote to Mr Rudd about the public safety issues but the correspondence has not been released and it is not clear if it will be examined in public at the commission this week.
Evidence has been given that Department of Prime Minister and Cabinet officials were present when risks were discussed, such as a meeting attended by department bureaucrat Andrew Wilson on February 18, 2009, at which the installer deaths in New Zealand were raised.
The meeting also involved discussions over whether Australian safety standards regarding insulation installation needed to be updated, which reportedly led to Mr Wilson being asked whether this would this would affect the program’s planning.
Mr Wilson is then alleged to have said: “You can’t disagree with a PM who is rating 73 per cent in the polls."
Evidence was also given to the inquiry that Insulation Council of Australia and New Zealand (ICANZ) chief executive Dennis Darcy raised concerns about the fast roll-out of the program with one of Mr Rudd’s office staff, Natalie Horvat.
Mr Darcy raised various issues, including that ICANZ would have preferred a four-year time frame, according to the statement he gave to the inquiry.
He stated that ICANZ had been recommending from the start against using foil insulation in the program because of safety concerns about foil being put across electrical cables “creating a risk of electric shock or electrocution”.
First to appear on Monday will be Mr Arbib with Mr Garrett due on Tuesday and Mr Rudd on Wednesday.
Families of the men who died will be given an opportunity to address the commission on Thursday. On Friday, former energy efficiency minister Greg Combet is to appear.
Matthew Fuller, Reuben Barnes, Mitchell Sweeney and Marcus Wilson died installing the insulation and poorly installed insulation caused hundreds of house fires as a result of the $2.8 billion program, which ran from 2009 to 2010.
Mr Fuller, Mr Barnes and Mr Sweeney were electrocuted and Mr Wilson died of heat exhaustion.
A coronial inquiry found the federal government did not adequately assess the risks and blamed the speed at which the program was formulated and rolled out for the deaths.
Mr Rudd has apologised unreservedly for the deaths, describing them as an “unspeakable tragedy” and said that he was “deeply sorry for what occurred”, given it was a government program.