Mould levels at the Calvary Mater hospital were breached on 185 occasions in the 16 months to August this year, with the worst about 50 times the limit.
Internal documents, obtained by the Newcastle Herald, further reveal the extent of the mould crisis, amid moves by the Minns government to take action to fix the problems.
The data showed relative humidity has been a significant problem at the Mater, further underlining problems with the hospital's heating, ventilation and air-conditioning (HVAC) systems.
Hunter New England Health said a NSW Health taskforce, formed last month to manage a remediation program at the Mater, met this week to pinpoint "the priority works to be delivered".
This will include remediation of the Mater's HVAC systems to "address moisture and mould risks in the hospital, including within the ICU and other priority clinical areas", an HNEH spokesperson said.
HNEH said it had conducted quarterly air quality testing at the Mater since April 2025.
The testing covers the ICU, emergency department (ED) wards 4B, 4C, 5B, 5C, 5D and 5E and uses a measure known as "colony-forming units per cubic metre".
ICU and ED results only cover January and August this year. Testing only began in those areas after a direction from NSW Health's Clinical Excellence Commission to test more high-risk areas.
Calvary documents show 5C is a haematology ward, 5B is medical oncology, 4B is a surgical ward and 4C is for general medicine.
Ward 5D, which recorded the worst mould results, was a haematology day ward. It was shut in late December last year, with outpatients moved to the physiotherapy department on level three.
Ward 5D recorded Aspergillus fumigatus levels up to 49 times the threshold that month.
"The physiotherapy area isn't suitable for haematology patients," a Mater staffer said.
The data shows the deadly Aspergillus fumigatus mould was detected at the Mater - the Hunter's main cancer hospital - 79 times.
This type of mould can seriously harm and kill immunocompromised people through invasive fungal infections known as aspergillosis and complications such as pneumonia.
The Herald has revealed at least 16 invasive fungal infections occurred at the Mater from 2019 to 2024. And about 120 families have registered for a class action into alleged mould-related deaths at the Mater.
As well as testing for Aspergillus fumigatus, several other mould species were tested, along with relative humidity and dew point levels.
An engineering report, commissioned by NSW Health in 2023/24, confirmed that the Mater's HVAC system had "no dehumidification".
The data showed thresholds for relative humidity and dew points were breached 119 and 101 times respectively at the Mater.
In January, mould testing detected Aspergillus fumigatus in four ICU rooms at two, nine and 11 times the threshold.
About five patients in total were transferred out of ICU, so the area could be cleaned. It was then decided to keep the ICU open, with additional HEPA filters installed.
The ICU also recorded numerous breaches of relative humidity and dew point levels in January.
Aspergillus fumigatus was again detected last month in two rooms in the ICU at three and eight times the threshold. In a third room, Aspergillus mould was found 14 times the threshold.
An HNEH spokesperson said "there is no single number that defines when mould levels are safe or unsafe in hospitals".
The data shows mould levels have improved at the Mater this year, as a parliamentary inquiry and Herald investigation added significant public scrutiny to the issue.
An HNEH spokesperson said air monitoring at the Mater "helps confirm controls remain effective while a whole-of-campus remediation program is developed".
"Air testing is used to track changes over time and guide cleaning and repair work. Results are reviewed alongside other clinical and safety information and are not used in isolation to assess risk," the spokesperson said.
"In general, indoor air should be similar to outdoor air levels. In high-risk clinical areas, hospitals should aim for very low or undetectable Aspergillus levels as a precaution.
"At the Mater, some areas have had results above precautionary targets for those with severely weakened immune systems. While these levels are not toxic and do not pose a risk to healthy people, immediate action has been taken to manage any potential risk."
The Minns government is finalising priority projects for a $400 million maintenance program on NSW public hospitals, with the Mater set for a significant slice of the money.
The HNEH spokesperson said the taskforce was "progressing its work to roll out a targeted remediation program" at the Mater.
"This will address priority building conditions, maintenance and performance issues across the facility," the spokesperson said.
The spokesperson said cladding remediation was progressing at the Mater, with work on the South Block southern facade and the Mater Institute building now complete.
The cladding work aims to stop leaks into the building that have been linked to the mould problem.
The government was under pressure from the Opposition and Greens in NSW Parliament's health estimates last month to resolve the Mater crisis.
This followed the parliamentary inquiry, which recommended the government terminate the Mater hospital's public-private partnership (PPP).
