A big review of Alcoa’s smelting and refining operations could be bad news for its 4,000 West Australian workers.

The US-based light metals company is tightening its belt, reducing global smelting capacity by 14 per cent and refining capacity by 16 per cent.

News reports say Alcoa’s Kwinana refinery is one of the company’s least profitable operations.

The latest announcement will cause concern for the 4,000 Alcoa workers at its Kwinana, Pinjarra and Wagerup sites in WA.

The three plants are responsible for about 11 per cent of global alumina demand.

The West Australian reports WA’s bauxite and alumina operations are considered world-class, but Kwinana has had efficiency issues related to its age, having opened in 1963.

“Our goal is to move down the global aluminum cost curve to the 38th percentile and the global alumina cost curve to the 21st percentile by 2016,” Global Primary Products President Bob Wilt said in a statement.

“The results from this review will help achieve those goals.”

Over the last few years, Alcoa has closed or divested 1.3 million tonnes of capacity.

Alcoa’s junior partner in Australia, Alumina Ltd, says the Portland smelter in Victoria is not part of the review.