Vietnam’s prime minister halted work on a $10.6 billion steel plant on Sunday over environmental concerns, aiming to prevent a chemical spill like the one last year at another steel plant, the local news media reported, citing a government statement.

The steel maker Hoa Sen Group, the plant’s investor, was not immediately available for comment. The company announced plans last year for the project, a complex of more than 4,200 acres that could produce millions of tons of steel a year.

Prime Minister Nguyen Xuan Phuc, saying he did not want another “Formosa incident,” asked related parties to clarify market demand and environmental impact, the website of the state-run Vietnam Television said.

Early last year, a steel plant run by the Taiwanese company Formosa Ha Tinh Steel Corporation was the site of one of Vietnam’s worst environmental disasters. A toxic waste spill killed tons of fish and devastated fishing communities along Vietnam’s central coast.