Sixteen maintenance workers on board the platform were evacuated amid the blaze, which razed the part of the platform that housed the compressor skid, Malaysia’s The Star newspaper has reported.
The 16 workers were doing maintenance work on the Tukau B drilling platform when the fire broke out at about 9.20am local time on Monday morning.
After the evacuation the fire was extinguished within an hour, Petronas said.
The Malaysian explorer said that the cause of the blaze was under investigation.
The Tukau B drilling platform is situated 31 kilometres from the shore near the Tukau oilfield in water depths of 60 metres.
The five injured workers were rushed by helicopter to Miri Hospital, where they are being treated for various degrees of burn injuries.
The most seriously injured worker, all of whom are locals, is being treated for second degree burns at the hospital’s red zone unit.
Two of the injured workers are staff members of Petronas while three are contractors.
Datuk Sebastian Ting, political secretary to the Energy Minister, told the newspaper he was informed by Petronas that it would send senior officials from Kuala Lumpur to investigate the incident.
“Petronas management said they view such incidents very seriously and will find out what actually triggered the fire,” Ting said.