South Korean prosecutors are seeking arrest warrants for five people over August's fatal tanker explosion at STX Offshore & Shipbuilding.
Four people died on 20 August during painting work in a product tanker's tank.
The Yonhap news agency reported that coast guard investigators have requested warrants for four STX workers and the head of a partner company.
The report said the explosion occurred when flammable gas from the spray paint flew into a lamp.
The 74,000-dwt tanker was reportedly due to be delivered to Greek shipowner Andriaki Shipping this month.
In May, six people were killed and more than 20 injured when a crane collapsed at Samsung Heavy Industries.
