Eight people were killed and seven injured in a Bangkok bank following a chemical accident. The incident took place in the basement of Siam Commercial Bank in the Thai Capital of Bangkok.

Bank authorities suspect that the incident happened due to negligence, when a fire prevention upgrade went wrong and the chemical sucked the oxygen from the building, reported BBC.

The accident took place on Sunday while the contractors were working on the fire fighting system.  The bank spokesperson also added that the incident happened in a vault storing documents in the head office.  The bank issued a statement saying: “gas pyrogens intended to extinguish fires opened and kept oxygen out resulting in injuries and death.”

An aerosol system called pyrogen was “inadvertently activated and exhausted all the oxygen in the area.”  Pyrogen needs a mixture of gases like potassium carbonates, nitrogen, carbon dioxide, carbon monoxide, nitrogen oxide and ammonia.

The statement also confirmed that “Eight people died as a result and seven injured people are in (the) hospital.”  According to the bank authorities, the accident happened due to the negligence of the contractors.

Charoen Srisasalak, the police colonel, referring to the workers said, “They were in the building for maintenance work.”  According to Bangkok Post, the firemen were delayed since when they conducted a test to detect fire, but they find out no heat. There was smoke coming out of the basement of the building. However, there was no fire or explosion.

The firemen said that when they finally tried to breaking into the building they were hindered by tightly locked bank-grade security doors. Although they manage to save three people, they could not enter either the basement or first floor.

The bank issued a press release and said that, as there was no fire or explosion so the bank will be open today. The bank statement also added condolences for the victims.

In January, there was a fire in Pickle Auctions Car Yard in Sydney. However,  no one was injured in this particular fire outbreak.