Unconfirmed sources, however, put deaths in the accident at five. Local sources claimed that 'a few' workers have remained unaccounted for since then and that the death toll may rise.

The dead are fitting foreman Sekander, 40, of Tulatoli of Sitakunda, and Majnu, 27, of Mathbaria in Pirojpur and Kajal, 22, of Habiganj. The injured were rushed to Chittagong Medical College and Hospital (CMCH) and the local health complex. Critically injured Bidhan Das alias Bidhu, 33, of Guyanpanchak under Boirag union of Anwara in the district was admitted into the CMCH.

Scrapping of MV Ocean was going on at the shipyard, owned by ZN Enterprise at Madambibirhat under the upazila, at around 2:00pm when the incident happened, according to the police and witnesses.

Witnesses said that the workers were trapped inside the vessel after the explosion.

Fire brigade personnel and police aided by local people launched rescue operations after the blaze was doused at around 4:30pm.

They recovered charred bodies of the three and rescued the injured, sources said.

Bidhu told The Daily Star at CMCH yesterday evening that they were cutting an oil pipe of the vessel when the blast occurred. He could not say what happened later.

Police and fire service sources said the ship caught fire due to a gas explosion.

The vessel was brought for scrapping to the ship-breaking yard around six months ago and a part of it was already cut after its arrival. Scrapping resumed yesterday after it remained suspended for around five months, sources said.