One or possibly two people would face arrest warrants, he said.

Five people wanted previously under arrest warrants surrendered to police on Friday and pleaded innocence, before being released on bail of Bt200,000 each.

The five are Jirawath Prempree, an engineer at Mega Planet; Somkid Chanhom, a foreman at Jones Lang LaSalle; Tripop Yangprasertkul, a manager at Jones Lang LaSalle; Kajornjit Promdeerach, an employee at Abit Multi System; and Somkid Tan-ngarm, an executive at Jones Lang LaSalle.

Most of those killed in the accident were working to improve the building’s fire-prevention system in the basement when it accidentally released pyrogen, which is widely used as a fire extinguisher. The aerosol fire retardant vapourised, depriving the basement of oxygen. Seven others were affected.

Two executives of Mega Planet, which was in charge of improving the fire-prevention system, have been charged with recklessness leading to the death of others.