The owners of Port Pirie's lead smelter have been fined $35,000 for leaking 700 litres of “toxic” sulphuric acid into waterways.

South Australia’s Environment, Resources and Development Court has ordered Nyrstar Port Pirie Pty Ltd to pay $35,000 as a civil penalty to the Environment Protection Authority over the discharge of sulfuric acid at its Port Pirie Plant in 2019.

In handing down the penalty today, Judge Muscat said the failure to prevent the discharge caused “potential environmental harm that was not trivial”.

An estimated 700 litres of sulfuric acid was discharged from the company’s smelter site into First Creek at Port Pirie on 31 January, 2019, with the potential impacts on the environment lasting until 2 February 2019.

In a previous hearing the court was informed that the acid moved through more than a kilometre of man-made waterways before entering into natural creeks and mangroves and out into Spencer Gulf.

The acid made the waterways more acidic and mobilised heavy metals. Fish were found dead in the creek; however, it was not clear if the deaths were as a result of the acid or whether they were the result of an algal bloom which occurred at the same time.

The investigation found that the acid ultimately escaped through a corroded valve with a series of failures and oversights leading to the incident including:

• failure to close a sample valve

• an incorrect assumption that the spilled acid was weak

• installation of an incorrect valve that was not corrosion-resistant

• failure of quality control systems to ensure the correct valve had been installed.

Nyrstar admitted the leak had the potential to cause environmental harm to fish and other plant and animal life in the creek which is an offence under the Environment Protection Act 1993.

Nyrstar cooperated with the EPA’s investigation into the incident and made a number of

improvements to its plant and practices to reduce the risk of a similar incident occurring in the future.

The company was also required to undertake an Environment Improvement Plan to prevent or minimise any environmental harm attributable to wastewater and contaminated stormwater management.