At least 27 people have been taken to hospital after being poisoned by carbon monoxide at a rave party in a bunker in Oslo .Five people were said to be in a critical condition, including two police officers who were the first at the scene.
The odourless and colourless gas is thought to be have been given off by portable generators, Norwegian media reported.
Local police said two people faced preliminary charges of trespassing and illegally being inside a bunker.
Up to 200 party-goers in their twenties and thirties had gathered in the bunker in the Norwegian capital for the rave, which used portable diesel generators to power lighting and sound systems.
Officers discovered the event early on Sunday when a police patrol met a group of confused young people in the park where the bunkers lies.
Emergency services found seven more people unconscious in the bunker.
The company that owns the bunker described the illegal rave as a “serious break-in” and insisted that it did not bear any responsibility, Norway’s VG newspaper reported. The entrance to the bunker had been previously closed with double-reinforced concrete but the new owners only secured it with wooden boards.
Carbon monoxide is an odourless, colourless gas produced by burning carbon-based fuels, including gas, oil, wood and coal.
Exposure can cause headache, dizziness, nausea, coughing, breathing problems and irritation of the eyes, nose, and throat. In some cases it can be fatal.