Orica has confirmed a small level of ammonium nitrate overflowed from its tank bund this afternoon.
The EPA was informed of the incident as soon as it occurred just after three p.m. today, according to the Newcastle Herald.
Around 20,000 litres of solution spilled over a bund around a tank and soaked into the ground.
HAZMAT teams were on scene to contain the spill.
There are no injuries reported.
According to an Orica spokesperson the solution was comparable to garden fertiliser, and there is no risk to the public.
New South Wales Health has also reportedly confirmed the low level of risk.
State environment minister Roby Parker was quick to announce her knowledge of the incident as soon as she was informed.
"Orica have reported that the incident occurred during pumping operations between tanks and the auto shut-off is believed to have failed," Parker stated.
Orica have halted operations following this most recent incident, which comes as the EPA lifts the prevention notice on the explosives manufacturer’s Kooragang Island plant.
Orica has been continuing with the pre start-up testing of the ammonia plant that it began over the weekend.
The safety tests involve turning on the steam system to test its integrity.
The steam will then be used to check a range of systems and to prove if the vent stack is clean of any contamination from the 8 August incident.
Gary Davey, from the EPA explained that "Orica had completed the works recommended by the independent engineer concerning the nitric acid plant and ammonia feed tanks and the Start Up Committee has reviewed these and had them independently verified".
Davey explained that the EPA has now "accepted the recommendation of the Start Up Committee to allow restart of the ammonia feed tanks and will lift the prevention notice today. This means that Orica will be able to operate the nitric acid plant".
According to the NSW Minerals Council "the closure of the Orica plant, which supplies around 80 percent of the State’s mines, has had an impact on operations. Supplies were low and not readily available from other sources. Some companies sought to source small quantities of explosives from as far away as Western Australia and Indonesia".
Downer EDI Mining’s executive general manager blasting Cliff Gale said it has been working to minimise the current disruption to explosive supplies in the Hunter Valley.
"We are also trying to help blasting companies manufacture their own emulsion by offering some of our ammonium nitrate suitable for melting, so as to not consume the very limited stocks of technical ammonium nitrate,”" he said.