Residents of Changjalu in Thimphu woke up to the sound of a massive explosion at around 5:22am yesterday.
The explosion blew the windows and doors of an apartment at the ground floor of a two-storey house.
There was no casualty.
Thimphu Police rushed to the scene with the bomb squad along with sniffing dogs to investigate what caused the explosion.
Senior Superintendent of Thimphu division, Colonel Dorji Khando said that there was no trace of an explosive.
“There were no splinters or a crater, a hole in the ground left when an explosive goes off, anywhere in that apartment,” he said.
They combed every part of the building but found nothing relating to explosives. Experts from various agencies examined the site and ruled out any foul play.
On closer examination, police found that the liquefied petroleum gas (LPG) cylinder in the kitchen had leaked.
Major Ugyen Wangdi said the cylinder was intact but empty.
The tenant was away at her relative’s place that night. She told police that she last used the stove at around 5pm on the previous day and turned it off. The cylinder was refilled recently.
The officer, who was an expert with the fire department, said that the gas stove pipe had worn out which could have been the point of the leak.
Police officials said that the apartment was small and had no ventilation. “They had sealed even the exhaust holes on the walls with ply boards,” Major Ugyen Wangdi said.
He said that the phenomenon is called a vapour cloud explosion.
“The gas being denser than air hung low in the room and the leak continued to build the pressure without exit points. It reached to the adjacent room and came into contact with the butter lamp which ignited the gas at once and caused the explosion,” he said.
“The resultant pressure from the ignition asserted equally in all directions and the weak parts of the structure, mainly the windows and doors gave way.”
“That is the only probable cause of the explosion.”
Neighbours said there was a loud noise like a clap of thunder and the floor shook.
“I thought it was an earthquake, and when I looked outside the ground floor was completely wrecked. There was no fire or smoke from the house.”
The house was fully damaged, with the single-partition inside the two-bedroom house and window panels wholly blown out. Witness saw shards and bricks lying all over the floor and outside.
The building suffered hairline cracks and window panes of the nearby buildings shattered.
RBP officials said that the public should turn-off regulators of LPG cylinders when not in use and to buy proper gas stove pipe to avoid such accidents.
The police said the case is still under investigation.