Thousands of litres of acid have leaked from a chemical plant in Port Kembla owned by beleaguered firm Orica.
The company has estimated that between 3000 and 4000 litres of sulphuric acid leaked from a pipe contained within a concrete culvert at the facility on Foreshore Road, but was contained by a safety system, the Illawarra Mercury reports.
In a statement, Orica said the leak was suspected to have come from a small hole in a "ship to shore" pipeline.
"There was no damage to the environment and no risk to the community. No employees were in any danger as a result of this leakage. The safety containment system functioned as designed," the company said.
Orica has not said how long the leak went undiscovered before the company self-reported the incident to the Environment Protection Authority (EPA) late Friday afternoon.
EPA officers were on site at the plant Friday evening as an investigation got under way.
State Environment Minister Robyn Parker said she was awaiting a report from investigators but was "shocked" that another incident had occurred at an Orica facility, just months after two other accidents at the company's plants on Kooragang Island, near Newcastle.
Orica shut several plants on the island after a leak of hexavalent chromium in August and an ammonium spill in November.
“I am advised that Orica self-reported the incident to the Environment Protection Authority late this afternoon and that Orica advised the spill was contained on site,” Ms Parker said.
“This is very disappointing and I am shocked that yet another incident has occurred at one of Orica's plants."
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