Bomb experts were flown in from Oslo on Sunday night to the house in Lund, Rogaland County, in western Norway. Fear of further explosions had kept police out of the building until it had been cleared by experts.
"The house is now cleared for further investigations. We will shortly begin our technical investigation of the house," Svein Arild Bringedal, sheriff in Lund, told Aftenposten.no on Monday morning.
Bringedal said that the bomb experts had concluded about what had been used in the explosions, but would not comment on the findings.
Five men, aged 20 to 26, were injured in a powerful explosion in the house on Sunday. The blast lifted the house off its foundations and moved the outer wall several centimeters.
"The house is more or less flattened inside. When we arrived it was burning a bit and there were several major and minor explosions. The explosions occurred in the cellar of the house, while up in the main floor of the house there was total chaos," said John Skåland, Lund's deputy fire chief.
Police said Sunday that the blast was linked to the men fiddling with fireworks but Bringedal would not comment on this on Monday.
Three of the men suffered minor injuries, two were flown to Stavanger University Hospital with serious injuries.
One of the men told newspaper Dagbladet that there was no dynamite involved, which police originally felt was likely due to the extent of the main explosion.
"That is bulls**t. We only used normal fireworks," the man told the newspaper.
On Monday an explosives expert told newspaper Stavanger Aftenbladet's web site that dynamite would have caused even greater damage to the house.
Both police and firefighters were astonished that the five men avoided worse injuries.
As recently as Friday evening police confiscated a small amount of dynamite in a car in the same area. Authorities have said there is no known link between the two incidents, but that it is natural to examine both of them more closely.
