Investigations into last month's fire at the Expo 2020 site discovered that a construction worker and an engineer have been hiding the truth about the cause of the blaze.
The fire was sparked after an accident during welding work at a debris-laden part of the site on May 11.
Dubai police said on Friday that a team of experts have succeeded in re-enacting the Expo 2020 fire scenario 12 times with "complete accuracy and professionalism", to reveal the main reason behind the fire.
The scientific experiments found that a sudden defect occurred during the welding of two pipes at the site which caused the fire.
“The welding work caused the temperature inside the tube to rise above 350°C which led to an internal ignition on the day of the accident,” said Major General Dr Ahmad Al Mansouri, Director of the General Department of Forensic Science and Criminology at Dubai Police.
Police said that both the construction worker and the engineer had denied performing any welding work on the day of the accident but experts managed to confirm that they were hiding the truth about the cause of the fire to evade responsibility.
“The fire experts and the criminal investigation team results showed that the welder, who works at the company executing the project, was carrying out his regular work tasks at the site and was welding two pipes when the technical fault occurred and made him stop the work,” said the police.
“He then restored the equipment back in the designated room, without following the safety procedures required in this situation."
It was also found that the worker then went to the bathroom, and within five minutes he noticed the site was being evacuated, because of the fire, so he went to the engineer in charge.
“The worker informed the engineer about the technical fault that occurred while welding the pipes and that he was not following the safety procedures,” said the police in the statement.
“The engineer asked him not to inform anyone of the defect, because there was no witness to his welding process, and therefore there is no need to involve himself and the company in the fire incident.”
Major General Dr Al Mansouri said that fire experts immediately began to inspect the cause of blaze, which started on the basement level, during the days following the extinguishing of the fire.
“Experiments have been conducted inside and outside the pipe to know the cause of the fire as the possible causes of such fires are either from cigarettes or through direct flame, the basement lights or a rise in the temperature of the pipe connectors,” he said.
“Based on the results, the fire started from inside the pipe and was caused by welding work, which the worker confirmed later on."
Expo 2020 Dubai has been delayed until next year due to the coronavirus pandemic.
The world fair's governing body in May approved plans for the emirate to host the event from October 1, 2021, until March 31, 2022, with the occasion to retain its Expo 2020 title.
The decision was confirmed after two thirds of Bureau International des Expositions member states voted in favour of the delay in light of the challenges posed to the international community by the Covid-19 outbreak.