Miwon Việt Nam's plant in Việt Trì, where the accident happened on Monday. — VNA/VNS Photo Trung Kiên

PHÚ THỌ — Four workers are dead and one hospitalised after an accident involving a biogas pit at Miwon Việt Nam's plant in Việt Trì City in northern Phú Thọ Province.

The four casualties were identified as Vũ Sa Huỳnh, 38; Lê Hùng Vinh, 42; Trần Văn Thắm, 59 and Dương Văn Sau, 38.

Nguyễn Trung Kiên, 35, survived and was sent to Phú Thọ General Hospital until his condition stabilises.

The accident occurred around 5:30pm on Monday.

The factory had outsourced a Hà Nội-based environment company to clean up the biogas pit in the plant. During the operation, Thắm and Sau, both cleaners, started suffocating and called out for help.

Huỳnh, Vinh and Kiên, working nearby, heard the calls and jumped down the pit to help. But they failed and all five suffocated and passed out.

The factory informed local officials, but when help arrived it was too late, with only Kiên surviving.

"An investigation is underway, and we will get to the bottom of this," said Hồ Đại Dũng, Deputy Chairman of Phú Thọ People's Committee.

Miwon Việt Nam is a subsidiary of South Korea's Daesang Corporation, specialising in food seasoning products. — VNS