As Origin plans to shutter its Eraring power station seven years earlier than expected in 2025, questions have been raised about what plans - if any - there are to deal with the roughly 100 million tonnes of coal ash waste dumped in unlined sites from not only Eraring but stations across the Hunter and Central Coast.

Innovative industry could provide the answer to both.

Coal Ash Community Alliance research coordinator Dr Ingrid Shraner is investigating safe uses for coal ash around the lake, collaborating with industry to develop new markets - but it has to make economic sense.

She has three criteria; it has to be environmentally safe, economically sound and able to process large quantities.

"We need to scale this up big time, we need an industry, we need to do something with this ash - given it is criminally cheap to put it into dams for the power stations and no other country does that in the world," she said.

An economist by trade, Dr Shraner has studied models used in the UK, and said trials that reuse coal ash as a structural lightweight aggregate are set to begin in the Hunter before the end of the next financial year.

She said the challenge has been a "lack of entrepreneurial spirit" and government support.

"You can buy the equipment off the shelf, you need the will and entrepreneurial spirit to cross-subsidise one product with the other, that's how you make this work," she said.

"You have to work closely with Transport for NSW, the Environmental Protection Authority (EPA), Infrastructure NSW, train engineers, create markets and off you go."

The reuse of coal ash isn't new - in fact, thousands of tonnes of the material have already been used in concrete pavement for the Woolgoolga to Ballina project, the M1 upgrade between Kariong and Somersby and the Scone Bypass.

Dr Shraner said the company, or several, that take this on will need to be truly innovative, in not just considering a circular economy but circular wealth - to repay the communities she said have paid the price in health and environmental degradation.

"It is definitely a debt the state of NSW owes to the people who had all the so-called environmental and health impacts from providing the state with power, so absolutely these are debts to the local people that have to be paid," she said.

"They need to take environmental, social and governance factors to the next level of being regenerative, of putting more back into the environment and community than they take out."

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Lake Munmorah resident and disability advocate Gary Blaschke said the health impacts need to be investigated.

"We have a massive environmental problem here impacting on the health of the people in the region," he said.

"We need some answers before it's too late for the whole region."

Mr Blaschke has been doing his own research, using Australian Institute of Health and Welfare and Australian Bureau of Statistics data to look at the number of people diagnosed with three or more chronic health conditions by suburb.

"It works out by population of those suburbs that Lake Munmorah and Mannering Park are most affected, with 16.9 per cent having three or more chronic health conditions," he said.

"The further you get away from the ash dams the less impact, Toukley has 16.8 per cent, Budgewoi 16.2 per cent and Avoca Beach at 8 per cent.

"I'm not saying it is directly due to the ash dams, I think it's cumulative air pollution from the stacks and coal ash that is causing it."

A NSW Legislative Council Public Works Committee Inquiry into the costs for remediation of sites containing coal ash repositories in March, 2021, recommended NSW Health immediately undertake an epidemiological assessment of the health of residents surrounding them with a report to be published in December.

A NSW Health spokeswoman said it is committed to understanding the impacts of coal ash.

"The Hunter New England and Central Coast Public Health Units are working with the EPA and local stakeholder groups in a collaborative process to develop a study methodology that will address community health concerns," she said.

"NSW Health will share any findings openly as the work progresses."

Origin, which operates the Eraring power station, maintains its monitoring program across emissions to air and water indicate the risk of environmental impacts on Lake Macquarie and the community is low.

"Site rehabilitation following any retirement of Eraring will be a long-term project that will consider the future operational uses for the site, including for the large-scale battery and ash dam management," a spokesman said.

"In 2020, Origin worked proactively with NSW EPA to seek the Eraring ash dam coal ash order and exemption which allows us to extract coal ash directly from the Eraring ash dam, enabling the use of the facility as a resource.

"Across the six-month period July to December 2021 inclusive, Eraring recorded an ash recycling rate of just under 79 per cent, and we'll continue to work hard to maintain high ash recycling rates by investing in new technologies and exploring new markets."

The Greens have called for coal ash dams to be emptied, and Shortland candidate Kim Grierson believes it's an opportunity to provide jobs in the Hunter and Central Coast communities that surround them.

"Those ash dams have been there in my lifetime, and it's time now for a clean up with a new industry to come out of it - we can make some money back," Ms Grierson said.

"I think this is a great opportunity to develop an industry that could operate and provide jobs over 50 years to empty out those massive areas."

The issue is that the industry isn't developed enough to consume large quantities of the material, Lake Macquarie MP Greg Piper said.

"I think that it could be 20 to 30 years before we see these industries, we have so much coal ash in NSW, let alone Australia, that there should be coal ash there for these industries for a long time to come," he said.

While he understands the community's concerns, he said it will take time to develop new markets.

"These people want to maintain the pressure and imperative, but the industrial or commercial repurposing of this material has to work," he said.

"If they can turn it into a commercial product, perhaps it won't be as profitable as running a power station - but if there is a profit someone should take it."

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