The investigator employed by council to look into asbestos mismanagement had no conflict of interest, a public inquiry has found.
And allegations of impropriety made by radio shock jock Ray Hadley over the issue were wrong.
Richard Beasley, SC, in the first stage of his public inquiry, looked into the appointment of two investigators - one to examine asbestos issues and the other to canvas allegations over the appointment of Mark Mulligan as a safety consultant at council.
He was also to consider allegations made by Mr Hadley that the asbestos investigator, Michael Tooma, was "best mates" with Mr Mulligan and should not have been investigating him.
In his report, Mr Beasley found that both the appointment of Mr Tooma and of Ms Scarlet Reid (to look at recruitment issues) had been appropriate.
He completely rejected Mr Hadley's claim of conflict of interest, which had prompted the then local government minister to issue a second suspension threat.
"Of the significant allegations made by Mr Hadley from February 13-15, 2018, none were factually accurate," Mr Beasley wrote.
Mr Hadley had claimed Mr Tooma was "best mates" with Mr Mulligan, whom he said was council's chief safety officer and oversaw asbestos management at council.
In fact, Mr Beasley found, Mr Mulligan had never been chief safety officer and had no significant role in developing asbestos policy.
Mr Tooma and Mr Mulligan had once worked closely together but any professional and/or social relationship finished in 2012.
Mr Tooma had thanked Mr Mulligan for his feedback in the 2012 edition of a book he wrote. This was the only allegation Mr Hadley got right, Mr Beasley found.
Mr Beasley also considered whether the costs of the investigation raised any matters of concern.
While noting that, at $600,000, it had been an "expensive exercise", he said: "However, given the complexity of the task, the seriousness of the matters being investigated and the breadth of Mr Tooma's terms of reference ... it was always going to be a costly exercise for council."
And, in fact, Mr Tooma had written off another $600,000 in fees for work in progress because of the uncertainty created by Mr Hadley's comments.
Mr Beasley concluded that council's process of engaging Mr Tooma and Ms Reid "was, in all the circumstances, prudent and appropriate".
He also found that council had responded properly to Mr Hadley's allegations.
Council welcomed the findings. The mayor, Mark Greenhill, said: "We thank the commissioner for the interim report.
"We note this interim report confirms that the council's decisions and actions in relation to the process of engaging independent investigators were reasonable and appropriate.
"The council will continue to work hard to ensure that its operations are safe and that our practices and processes support our workers and the community."
He added that he "would also like to thank Michael Tooma for his work and reflect that he is an eminent lawyer whose recommendations have greatly assisted the council in the development of its improvement plan".
A spokesperson for the law firm Clyde & Co, where Mr Tooma is a partner, said in statement: "We welcome the Commissioner's report which concluded the engagement of our firm was in all circumstances prudent and appropriate... The Commissioner's report noted the high quality of our detailed and thorough investigation."