The EPA has ordered a report on the latest flare ups at the Kooragang Island explosives plant.
It ordered Orica to provide information on what causes the hydrogen gas discharges to ignite during its ammonia plant restart process, the Newcastle Herald reports.
On Sunday and Tuesday, flames were reported to have shot up to 20 metres from the plant’s stacks.
The explosives manufacturer has stated that it is investigating all possible causes of the second incident.
According to Orica’s site manager Sean Winstone, "while it is not part of Orica’s normal start-up procedures, the ignition of hydrogen from a vent stack is not a unique event. It has happened in the past both at Orica and at other plants and we have procedures in place to manage it.
"Hydrogen, a colourless, odourless, non-toxic gas which produces water when it burns, is produced by the plant and is discharged from vent stacks during the restart process. Some plants will deliberately ignite it during the restart process. At Orica we do not deliberately light the gas as part of our standard procedures but the flare poses no risk to the community or to the plant," he added.
However, Correct Planning for Mayfield spokesperson John Hayes told the Herald these incidents were cause for concern.
"Are these fires in breach of the start-up conditions and, if so, what is being done about it?" Hayes asked.
The EPA confirmed there was no risk to the community from the flare ups, with chief environmental regulator Mark Gifford stating that "there was absolutely no environmental impact as a result" of the flare ups.
Gifford went on to say that it will have no effect on the plant’s restart process.
"As the flare poses no risk, we have continued with the restart of the Ammonia Plant which has been progressing well," Winstoned added.
"Over the weekend, we successfully restarted the High Temperature Shift Catalyst Vessel which is the section of the plant which was the source of an emission of hexavalent chromium on 8 August last year. This was done without incident and means that there is now no hexavalent chromium remaining in the plant," Winstone explained.
However Gifford added that "Orica needs to adhere to the Start Up Committee’s and the EPA’s requirements on an ongoing basis to demonstrate a rock solid commitment to operating safely, from both a public health and an environmental point of view and the EPA will continue to keep a close eye on their operations."