At least four people have been killed in a blast at a chemical plant in South Korea.
Owners of Ulsan's Hanwha Chemical Corp said that the explosion took place during welding work to expand a waste water disposal facility, reported the BBC.
A fire brigade official said that gas from the waste water, which had piled up inside the tank, caught fire from the welding torch.
Meanwhile, a probe to determine if the explosion was caused by negligence is under way.
The plant manufactured polyvinyl chloride used in wide range of products, such as cling film.
