Aluminium giant Alcoa will permanently shut its Kwinana alumina refinery, delivering another blow to Western Australia’s industrial strip and putting 220 jobs on the line.

The Pittsburgh-based group confirmed the 2.2-million-tonne-a-year refinery would not restart, more than a year after operations were curtailed, citing the facility’s age, high operating costs, market headwinds and declining bauxite grades.

“Alcoa operated the Kwinana refinery for a number of years in a challenging environment and made the difficult decision to permanently close the facility after unsuccessfully exploring multiple options for a sustainable path to restarting,” said executive VP and COO Matt Reed in a statement on Tuesday.

The decision will trigger restructuring charges of $890-million in the September quarter, including $375-million of non-cash impairments. Cash outlays of about $600-million are expected over six years to cover asset retirement and employee liabilities. About $75-million will be spent in the December quarter.

Alcoa said it would work with the Western Australia government on future land use and potential redevelopment opportunities for the site. Its port and rail facilities at Kwinana would continue operating, as would its other Western Australia and Victorian assets.

The company has operated the refinery for more than 60 years, and said employees, contractors and suppliers had made a “major contribution to Western Australia’s economic development and prosperity”.

The announcement drew fire from the Nationals WA, which said the closure was a devastating blow to households and the state’s economy.

“These 220 additional job losses brings the total to around 1 000 direct losses for Alcoa workers in recent months, with a further 5 000 flow-on jobs at risk across the supply chain and wider economy. That is thousands of households facing uncertainty,” the party said in a statement.

“The Cook Labor government will try to spin this as a ‘future redevelopment opportunity’ but the reality is it represents the loss of a major industrial asset on their watch. This is a damning legacy for a government that has failed to protect jobs, failed to support the resources sector, and failed to provide the right policy settings to keep WA internationally competitive.”

The Nationals said WA’s resources sector was “under siege from red and green tape, heavy-handed industrial relations changes, and a Labor-driven push for unionisation that is driving up costs and eroding investor confidence”.

Alcoa will retain some workers beyond 2026 to prepare the site for redevelopment, but the refinery’s closure cements the end of an era for one of Kwinana’s most recognisable employers.