Smoke from the basement prompted the fire extinguishing system of the building to release the gas pyrogens because the chemicals sucked all oxygen from the building. Firemen found tightly locked doors by bank-grade security. They managed to rescue three people on the ground floor but could not access either the basement or first floor. The bank identified those who died as a security guard and seven contractors. Bangkok’s Erawan medical emergency center said five people died at the site of the accident and three died later at a hospital. It was no fire or explosion according to the bank issued press release late Sunday night and it’s considered “an accident caused by the negligence of the contractor hired to improve fire protection of the building”. Police were still investigating the accident.