BANGKOK - Bangkok's CentralWorld shopping mall, which was hit by a fire earlier this week that killed two people, will reopen for business on Friday (April 12) after officials conducted inspections of the mall's interior and said its structure had not been damaged by the blaze.

The Bangkok Metropolitan Administration (BMA) and Engineering Institute of Thailand (EIT) said on Thursday that the fire on Wednesday was likely caused by the combustion of gas in the mall's waste-treatment facility, located on Basement 2, The Nation reported. They said the fire then spread to the eighth floor via an air vent.

Mr Siriwat Chaichana, an adviser to EIT, said that although two people had been killed and more than 20 others injured in the incident, the team of engineers have concluded that the fire was not large enough to cause substantial damage to the building's structure.

Apart from the small fire-affected areas on Basement 2 and the eighth floor, the mall can open for business as normal, the team said.

"After inspecting CentralWorld, it was found that the fire was too small and did not burn for long enough to affect the inside of the concrete structure, so the building is considered safe to open to the public again," Mr Siriwat said.

Mr Amorn Pimanmas, secretary-general of the Council of Engineers, said the fire began at the waste-treatment facility room on the Basement 2 floor, leading the team to conclude that the fire was sparked by the combustion of gas.

As for why the fire was worse on the eighth floor, Mr Amorn said that an air vent delivered the smoke and heat to the upper level, triggering a second fire outbreak there.

Meanwhile, Mr Phinit Arayasilpathorn, the chief of Pathum Wan district, in central Bangkok where the mall is located, said he has ordered the temporary closure of an 80 sq m area on Basement 2 and a 400 sq m area on the eighth floor until the repairs are completed.

He also assured that the mall's fire-alarm system is working properly, after complaints from some people in the mall during the incident that the alarms had not sounded promptly.

"The department store is big and full of customers, so operators must consider preventing mass panic, which could harm more people than the fire itself. They gently alerted customers and guided them in an orderly manner to the exit," he said.

However, shopper Sansith Koraviyotin, who was at CentralWorld during the fire, said there were no alerts issued and the mall operator had underestimated the fire.

"Even after I smelt smoke and people began to evacuate, many were still sipping their coffee, and nobody warned them of the danger and asked them to leave. People were still allowed to use the lifts," Mr Sansith said. "Furthermore, I heard no sirens to warn people in the mall that there was a fire and that we were in danger!"

He said it was fortunate that the fire on Wednesday had not been too severe, but cautioned against what he said was the slow evacuation of shoppers and staff, adding that it would have been a bigger tragedy if the fire had gotten out of control.

Meanwhile, Police General Hospital reported that five of the 10 individuals injured in the fire had recovered and returned home on Thursday.

Labour Minister Adul Sangsingkaew said the families of the two victims will be compensated.

The Thairath Online website reported on Thursday that two men had jumped from the building during the fire, with the former killed by the fall and the latter pronounced dead at the hospital.

The family of Mr Sakchai Chalernlarp will receive 1.4 million baht (S$59,600) while Mr Arthit Kamsai's family will receive 1.39 million baht. The sums will be presented to the victims' families next Thursday.

Those injured will also have their medical expenses covered.