Quote Originally Posted by IntheGroove View Post
"According to The Swedish Accident Investigation Authority , the fire was caused by welding work with an electrofusion welding on the exterior of the construction, near one of the slides."
Electrofusion is a normally a safe welding technique and does not make explosions. It may have been the spark that set it off but there must have been another major underlying factor that fueled such an explosion. It also appears as if the fire stared interior the building at the back.