Pieces of asbestos were deliberately planted at sites around the Mountains to sabotage clean-up efforts, the public inquiry has been told.
And documents were allegedly leaked to radio shock jock Ray Hadley to show council in a bad light.
Two council workers testified that on a number of occasions asbestos, or material that looked like asbestos, had appeared at sites after they had been thoroughly cleaned and inspected by SafeWork NSW officers.
These included the Heatherbrae child care centre in Lawson, Lawson Mechanics Institute garden bed, Wentworth Falls toilet block, Glenbrook tourist information centre, Lapstone Park garden and council depots at Springwood and Katoomba.
Alan Harris, an asbestos management consultant engaged by council in December 2017, told the inquiry he believed that someone or some people within council were deliberately working against asbestos efforts.
"One of the significant issues was the attitude of some individuals which SafeWork raised to me as being very problematic and not being helpful at all," Mr Harris said.
The commissioner, Richard Beasley SC, stepped in: "SafeWork raised with you?"
- That people within council were impeding them in providing assistance to the council?
- That is true, sir.
Mr Harris said there was "open disagreement between people for decisions made by council. There was a utilisation of broadcast and print media ... There was the leaking of documentation in a way that was to show the council in an adverse light."
Mr Harris said it also became increasingly clear that material was being planted at some sites.
"I became concerned, and it was not just a concern of myself personally, that at a number of sites which had been subject to very significant inspection and review and clearance certificates ... and inspection indeed by SafeWork themselves, that at a later date reports would be coming through that the site is contaminated and again this information was being broadcast on public media."
When a piece of material was found on mulch in a garden bed at the Mechanics Institute, he even suggested a 24-hour security guard be placed there "to ensure that there is no chance of any materials being introduced" to the area.
Mr Harris said a senior manager with council, Rhett Hahn, had contacted SafeWork at least six times about sites of alleged contamination but nothing had been found.
Mr Beasley asked: "So his comments to SafeWork caused SafeWork to conduct a level of investigation that resulted in no notices and no requirement for SafeWork to take any steps?"
"That happened on not less than six occasions, sir," Mr Harris said.
He was later told that SafeWork had banned Mr Hahn and a Michael Kaveroff from making direct contact with any inspector.
Mr Harris said after repeated incidents of planted material, he suggested council leadership might contact the police "because these are borderline criminal acts".
Council did, in fact, make a report to police but no charges were ever laid.
Mr Harris told the inquiry the asbestos response team "was being attacked repeatedly with assertions of improper conduct and activity".
Mr Beasley asked: "Just pause there. Attacked by who and when?"
"Mr Rhett Hahn was making a series of allegations to SafeWork that the asbestos response team was not managing its responsibilities in accordance with how they should be doing so," Mr Harris replied.
Fellow council worker Jason Adams, who was program leader, hazardous materials, told the inquiry he had personally seen material which must have been planted.
In one case, he engaged contractors to clear asbestos at Katoomba depot's administration block. They worked on a Saturday when there were no staff present and issued a clearance certificate saying it would be safe to re-occupy. But by the Monday there was dust everywhere and Mr Adams had to close the building down.
Mr Adams also said someone planted a piece of material in the under-floor area at Heatherbrae. He had been there just 24 hours earlier and seen nothing but on the day SafeWork was due to inspect he saw a piece "bigger than a dinner plate" and "just inside the door so quite obvious".
Earlier, Grant McKay, who was manager of governance and risk at council, said Rhett Hahn had refused to be on an asbestos management project team.
Peter Singleton, representing council, asked: "How did Mr Hahn ... have an effect on the work of this team?"
Mr McKay: "My very strong suspicion is that he worked against the interests of the team, but I can't cite specific examples of that. He certainly wasn't a champion of what the team was doing out in the field."
Mr Beasley: "What would be his motivation for that? If you were right that he was working against the team, what would be his motivation?"
Mr McKay: "He was denied the opportunity to act as general manager, city services."
Q. "Denied the opportunity for promotion?"
The hearings concluded last Friday.