Another chemical leak at the embattled Kooragang Island chemical plant has seen two people taken to hospital.
The ammonia gas leak late 9 November at the Orica plant reportedly caused two people in Mayfield East to suffer breathing difficulties, according to The Newcastle Herald.
This latest incident, in which approximately 900 kilograms of ammonia gas escaped from a 20 tonne vat over 15 minutes, is one in a series of chemical leaks since August.
However, Orica say the 900 kilogram estimate was a "worse case scenario".
The chemical plant has been under increased scrutiny from the Government and environmental bodies after hexavalent chromium and arsenic leaks.
According to a Fire and Rescue spokesperson there were five vats on site, four of which had been shut down due to heavy storms.
However "the fifth vat was still operating and for reasons that are under investigation the pressure valve operated," they told the Herald.
Orica stated that it contacted regulatory bodies as soon as it was notified that vapour had been detected.
"The incident is currently under investigation and Orica will provide further information as it becomes available," it said.
The company has had to face tougher laws on pollution breaches since the initial incident in August.
Orica CEO Graeme Liebelt said in a statement environmental rules were a large part of the company’s work and it supported regulatory changes.
“The regulatory regime is integral to our operations and we support action to advance this system,” he said.
“We have been working diligently since the [August] incident to address concerns, particularly those regarding emergency response protocols and engagement with the community.”
Current laws require companies report chemical incidents “as soon as practicable” but the new changes will stipulate that incidents be reported immediately.
Earlier this month, residents near the Kooragang plant had raised concerns over plumes of brown smoke coming from the facility.
Orica spokesperson Nicole Ekert stated that the fumes were emitted by the No.1 nitric acid plant at the Kooragang site.
Since 9 November’s incident, the Greens have called for the facility to be shut and its operating licence revoked.