BlueScope Steel has been fined thousands of dollars after water containing cyanide at triple the legal levels found its way into a drain leading to the Port Kembla Inner Harbour.
The incident, which occurred in September 2016, killed a number of fish in the drain after warnings about the leak were ignored.
The NSW Environment Protection Authority (EPA) fined the Port Kembla steelmaker $15,000 over the incident.
A water valve had been left on, causing water and coke oven gas condensate, which contains cyanide, to overflow into an internal drain at the premises.
EPA officers attended the incident and observed approximately 10 to 15 small dead or distressed fish in the drain.
The EPA said no impacts to fish in Port Kembla Harbour were reported.
Testing of the discharge found cyanide levels of up to 0.3mg/l, which is three times the level allowed by BlueScope’s licence.
The overflow triggered alarms, but these were believed to be false and were ignored.
EPA Manager of regional operations in the Illawarra Peter Bloem said the environmental damage and death of the fish occurred because the workers ignored proper procedure.
“Impacts to the local environment could have been prevented,” Mr Bloem said.
“The overflow triggered alarms, but these were believed to be false and were ignored.”
Mr Bloem said BlueScope responded to the incident promptly and took steps to reduce the environmental impacts. They also carried out water quality sampling and analysis.
“As well as issuing the penalty notice, the EPA has also issued an official caution to BlueScope Steel and added a Pollution Reduction Program to their environment protection licence to further safeguard the environment,” Mr Bloem said.
The caution was for failing to operate the steelworks in line with the conditions of its licence.
As part of the reduction scheme, BlueScope must investigate ways to stop the water and cyanide leak from happening again.
The EPA said the company had already implemented additional controls and updated their standard operating procedures to prevent a recurrence.
BlueScope was contacted for comment.