The NSW Environment Protection Authority has commenced a prosecution against the owners of Vales Point Power Station in relation to a fish kill at Mannering Park last year.
The Land and Environment Court prosecution alleges that Sunset Power International Pty Ltd trading as Delta Electricity failed to maintain its chlorine dosing plant in a proper and efficient condition.
This resulted in a faulty valve that caused a discharge of concentrated sodium hypochlorite into waters leading to Wyee Bay.
The offence carries a fine of up to $1 million.
NSW EPA Chief Executive, Tony Chappel said the prosecution followed a comprehensive investigation into the incident, which was the second of two fish kills that occurred in the area over a six week period in August and September last year.
"Alongside the community, we expect Delta to meet high standards given the proximity of the Vales Point Power Station to Lake Macquarie," he said.
"Our investigation found that Delta could have prevented the fish kill if they had adequate equipment and processes in place.
The fish kill resulted in the deaths of thousands of marine creatures around Mannering Park. They included mullet, bream, bat fish, whiting and a white spotted eagle ray.
Mr Chappel said the EPA was pleased that Delta had since upgraded its systems and that the lake's water quality had returned to normal levels.
"We will continue to ensure Delta acts in accordance with its environmental responsibilities to prevent future events and protect the environment in Lake Macquarie," he said.
"We know this was a distressing event for the community and I want to thank them for their patience as we worked through the investigation."
The EPA alleges the incident is a breach of Delta's environment protection licence and an offence against section 64 of the Protection of the Environment Operations Act 1997.
A Delta spokesman said, while the company understood the EPA had commenced proceedings relating to the fish kill, it had not been provided with a copy of the allegations so it was unable to comment further.
"Delta takes these allegations seriously and will consider its response once the details are properly provided by the EPA. As the matter appears to now be before the courts it is also inappropriate for Delta to comment further at this time," he said.
Swansea MP Yasmin Catley, whose electorate takes in Mannering Park, said the community would be pleased to see action had been taken in relation to the fish deaths.
"Industry needs to understand it has a responsibility to operate in line with community and environmental standards," she said.
"I thank the community for their patience while the Environmental Protection Authority has undertaken its investigations. I also acknowledge the tireless work of the EPA."
Hunter Community Environment Centre spokeswoman Jo Lynch praised the EPA's investigation.
"The NSW EPA's findings validate long-running concerns held by many residents of southern Lake Macquarie, that Sunset Power International does not take its responsibilities to the community or the environment seriously," she said.
"Community members who saw for themselves the severity of this unacceptable oversight can be assured that Delta Electricity will be subject to the legal scrutiny they have earned through complacency and a failure to maintain equipment which led to the regrettable and entirely preventable loss of marine life in the estuary that is the lifeblood of the community."
The EPA arranged for the installation of a Smart Buoy data logger to monitor water quality at Wyee Bay following the fish kill events.
The EPA issued Delta with a licence variation last year to maintain significantly tightened emission standards for nitrogen oxides (NOx) from Vales Point.
Delta is also required to undertake a range of activities to protect the local environment including to implement a seagrass monitoring program and a Coal Ash Repository water sampling plan.
Billionaires Trevor St Baker and Brian Flannery sold the Vales Point plant in December last year to Sev.en Energy, a company owned by Czech billionaire Pavel Tykac.
Live data from the EPA's Smart Buoy data logger is available at: https://www.epa.nsw.gov.au/working-together/community-engagement/updates-on-issues/mannering-park-lake-macquarie-fish-kills
