Up to seven million litres of potentially toxic chemicals spilt at Alcoa refinery in Western Australia

Up to seven million litres of potentially toxic chemicals has been spilt at an Alcoa refinery in Western Australia, prompting an investigation.

The incident happened at Alcoa’s Wagerup alumina refinery. Picture: Joe Castro/AAP

Up to seven million litres of potentially toxic chemicals has been spilt at a refinery in Western Australia, prompting an investigation.

Workers at Alcoa’s Wagerup Alumina Refinery noticed “a loss of process material” from a tank about 10.30pm on Tuesday. Nobody was injured.

The Department of Mines, Industry Regulation and Safety as well as the Department of Water and Environmental Regulation are now investigating what happened.

An Alcoa spokeswoman said the spill had been contained within the operating footprint.

“The majority of the material (was) captured by the bund directly underneath the tank and on adjacent bitumen,” she said in a statement on Friday.

“No employees were in the immediate vicinity at the time of the incident and Alcoa acted immediately to commence clean-up of the site.

“The investigation into the cause of the incident is ongoing.”

Government departments are investigating what happened at the Alcoa site.

A Department of Water and Environmental Regulation spokesman said potentially alkaline mining process material escaped through a hole in the tank floor and entered the secondary containment bund.

“The secondary containment bund filled with material and overflowed to the tertiary containment system, with a small amount flowing to unsealed ground within the Wagerup processing area,” he said.

“Alcoa has advised that the preliminary estimate of material lost from primary containment is seven million litres, with the majority contained to the secondary and tertiary containment systems.

“No material has entered the environment surrounding the plant and is not expected to enter the environment or waterways.”

The department will assess whether there has been a breach of the Environmental Protection Act.

Alcoa’s spokeswoman said the company was working with both government departments.

DMIRS director of dangerous goods and petroleum safety Steve Emery said inspectors were onsite on Friday.

“As a result of further information provided by Alcoa on Thursday, DMIRS decided that it was appropriate for inspectors to visit the site to understand the nature, extent, causes of the incident and any implications in regards to safety and compliance with the requirements of the relevant legislation,” he said.

The refinery, south of Perth, produces about 2.8 million metric tons of alumina each year.