The state's environment watchdog is continuing to investigate the circumstances surrounding a major dust pollution incident at Eraring power station's coal ash dam last week.
Concerned residents recorded thousands of tonnes of coal ash blowing in a northerly direction across the lake during an extreme weather event on Tuesday.
Argenton resident Fred Gleinzer said he was particularly concerned about the impact on those with respiratory illnesses.
Residents who complained to Origin Energy were told the company had to divert resources away from dust mitigation to managing an imminent bushfire threat.
An Environment Protection Authority spokesman confirmed on Tuesday that the incident remained under investigation.
An Origin Energy spokesman said the EPA had requested the company to provide a report on the incident.
"Last Tuesday Eraring was operating on significantly reduced staffing levels due to the catastrophic bushfire conditions and risks posed by an active fire within 1.5 kilometre of the station," he said.
"Unfortunately this meant we were unable to operate some of our dust suppression tools like water cannons to their full capacity. We are currently preparing a report on this incident for the EPA."
The NSW Department of Planning last month recommended approval for an expansion of the 35 million tonne coal ash dam by 5 Million cubic metres.
The proposed expansion would extend over the abandoned Awaba Colliery, parts of which extracted coal to within 20 metres of the surface. At least one sinkhole has already opened up within the area earmarked for the expansion.
The Newcastle Herald reported in July that the state government has no plans to remediate coal ash dams at Eraring and Vales Point following their closure despite a growing body of evidence pointing to the harmful effects of coal ash.
Similar remediation projects undertaken elsewhere have cost hundreds of millions of dollars to complete.
Under the terms for the sale of the power station assets, Origin Energy and Delta Electricity are liable for the cost of remediating pollution which they cause during their period of operation.
The state government remains liable for the coal ash pollution that occurred prior to the 2015 sale.
Pollution incidents can be reported to the Environment Protection Authority hotline on 131 555.