The incident occurred around 8:00 am at the Binh Minh Wood Production Company in Dong Nai province, with Vietnamese media reporting it was caused by a malfunctioning boiler.

“Arriving the site, I saw a horrifying scene: debris scattered everywhere and several bodies lying in the yard,” according to a witness quoted by news site VNExpress.

State media photos of the site — where some 30 employees were working at the time — showed part of the building had collapsed, with the corrugated iron roofing flung to the ground.

The blast in Vinh Cuu district took place just a few minutes after workers finished maintenance on the boiler.