A furnace at a steel factory in the northern city of Hai Phong exploded Sunday, shocking nearby residents, but no casualties were reported.
Residents of Quan Toan Ward said they heard between four and five explosions at around 6 a.m., and saw a column of fire rising from the factory operated by the Tan Huong Company.
Le Duy Chin, the factory's manager, said the incident started from furnace No.4 and probably happened when workers accidentally put wet raw materials into the furnace which was then burning at 1,500 Degrees Celsius.
It made the steel in the furnace burst out, causing explosions as it flowed to cooling water circles, he added.
According to Chin, three workers were then at the site, but no one was injured.
An investigation into the accident is underway.
Four furnaces at the factory with a total capacity of some 500 tons of steel a month were put into operation early this year.
The factory, located next to the Cong My residential area with 300 families, has attracted frequent complaints and accusations of environmental pollution, but no action has been taken by authorities so far.
Nguyen Van Huong, director of the Tan Huong Company, said they were figuring out solutions to the environmental problems created by the factory.