The head of Canberra's Asbestos Removal Taskforce says more Canberra homes are likely filled with dangerous Mr Fluffy insulation, but it would be impossible for an investigation to locate every one.
Geoffrey Rutledge said three homes added to the list of properties with Mr Fluffy asbestos since November 2019 were likely a DIY job missed by visual inspections conducted in 2014.
"Could it happen again? I think the answer is yes it can, I don't know what that number is but I wouldn't be saying the answer is zero," he said.
A widespread investigation in 2014 found 1022 Canberra homes were filled with the deadly insulation which led the ACT government to launch a buy back scheme to demolish the affected dwellings in a bid to rid the city of the substance.
At the time, a visual inspection of homes was undertaken with the expectation the entire home would be filled with the deadly insulation, rather than one section.
"What you were looking for was a house filled with loose-fill asbestos so a simple look in a man-hole would reveal that," Mr Rutledge said.
"I don't think they were tasked, and I don't think the expectation was, that at that time you would have Mr Fluffy in part of the home and not the full home because the delivery method was pumping through the roof."
The three latest houses identified, in Rivett, Fraser and Weston, were likely a DIY job that didn't meet those expectations.
"A homeowner has bought a bag or two or Mr Fluffy, installed it themselves in part of the ceiling and then either covered it with additional insulation themselves or later," Mr Rutledge said.
In each case, homes identified recently were found by a tradesperson undertaking work and finding the material.
In a 2014 report, then taskforce head Andrew Kefford recommended "in the interests of ensuring other people are not unknowingly exposed to loose fill asbestos fibres" in "missed houses", asbestos assessments be mandatory for renovations or the sale of homes built before 1980.
This recommendtion has not been implemented.
However, Mr Rutledge didn't think remaining asbestos-ridden homes would have been located earlier even if it had been.
"I'm not sure we would have found them any quicker, I think the mandatory training of tradespeople has been very effective," he said.
The taskforce won't investigate the possibility of more DIY jobs, a task Mr Rutledge described as impossible.
"We've done the awareness raising with tradespeople and the community is well aware of asbestos risk," he said.
"We need to be aware of the dangers of asbestos and when undertaking renovations we would recommend a full asbestos assessment before undertaking those renovations."
A former Mr Fluffy homeowner, Felicity Prideaux has been a vocal advocate for the hundreds of Canberrans impacted.
It didn't come as a surprise to her more Canberra homes would need to be demolished.
She labelled the decision not to implement the 2014 recommendation a "major failing" and called for the next ACT government to implement it.
"This is not Labor versus Liberal, this goes across Commonwealth and local jurisdiction governments of both persuasions," she said.
"We won't go away. We need to have these things sorted out, we need to understand what's happened and we need to ensure that this doesn't happen again."