BINTULU: Chemical company OCiM continues to operate as usual, except for the site of last night's explosion, which was closed for investigations, said the authorities today.

Samalaju Fire and Rescue Department head Irwin Abidin said the department is investigating the cause of the explosion at the Samalaju Industrial Park here.

He said the explosion did not involve piping or vessels, and caused damage only to the shelter panel wall.

He said according to information received from the company's security officer, the explosion was likely caused by a hydrogen gas leak from a filter vessel that had built up in the shelter at the PS1 A1 section.

"There was no operational action taken by firemen at the scene. They only monitored and collected information from the factory on the explosion."

He said the Samalaju station received a call from OCiM on the explosion, which is said to have happened about 11pm.

He said the explosion happened on the eighth floor of the building.