The system activated due to a false alarm on Sunday, resulting in the deaths of eight people and injuries for seven more.

A police investigation initially found that an alarm had sounded but workers who were installing additional fire-protection systems didn’t flee the scene, while security guards initially thought it was a fire drill, an informed source said. When a foreman arrived, staff realised the pyrogen system had been activated and posed a hazard, the source said. Police are waiting for more test results as their investigation continues.

Mega Planet Plc executives Adisorn Poda, 50, and Napong Suksa-nguan, 44, were brought to court yesterday as police requested the first 12-day detention, objecting to them being granted bail on the grounds that they posed a flight risk. The two men maintained their innocence, and were granted bail release at Bt500,000 each.

Arrest warrants will also be issued for several more suspects, according to Acting Metropolitan Police Commissioner Pol Maj-General Sanit Mahathaworn.

After the interrogation of the two men at Phaholyothin Police Station yesterday, Sanit said they had heard the charges against them, which are punishable by 10 years in prison and Bt20,000 fine. Adisorn, who is the firm’s authorised signatory, and Napong, who is in charge of operations, surrendered to police earlier yesterday expressing regret for the incident and a willingness to compensate the victims’ families, Sanit said.

The police inquiry found Mega Planet had outbid four other companies to win an SCB contract to install fire-safety systems at the bank’s head office. Police are now considering whether the contract provided for adequate accountability, Sanit said, adding that police would also check the details of the firm’s sub-contractors.

Police are confident of recommending prosecutions, he said, adding that more arrest warrants would be issued, for those involved in the firm’s operations.

One of the injured victims, SCB foreman Saran Daennong, who remains at Paolo Hospital Chokchai, said he had just started his shift five minutes earlier in a document-storage area at the bank when he heard the alarm.

As he rushed towards the origin of the sound, he said, he heard an explosion and saw that a pipe above his head had broken.

In the subsequent power blackout, there was a lot of smoke in the area and a strong odour of gas.Saran said he heard several workers call for help a few times before they fell silent. He then passed out and regained consciousness while being treated in a rescue vehicle.

Meanwhile, relatives of two of the victims, Saifon Laenkhot and Kannikar Sinsiri, who had a daughter together, picked up their bodies and asked for urgent assistance to care for the orphaned girl.

In related news, the president of the Engineering Institute of Thailand (EIT), Suchatvee Suwansawat, said there were three questions to be answered during the investigation of the scene: Why had the pyrogen system activated in the absence of a fire?; what were the causes of death given Mega Planet’s claim that the system did not eradicate oxygen in the area?; and why couldn’t the victims escape?

The EIT would also inquire whether building caretakers had shut down the pyrogen system before workers began the new installation, Suchatvee said.