Police have begun an investigation after a rave party in an old fortification in Cologne that left at least 18 people injured. On Saturday, 18 participants in an illegal event at the Fort X location – part of the old fortifications – were hospitalized with carbon monoxide poisoning. A police spokesman said on Sunday that it must now be clarified who was responsible for the party and the health-threatening situation. Officials were on site to collect evidence and criminal proceedings for bodily harm were initiated.

The fire department responded to an emergency call on Saturday night. As soon as they entered the facility, the carbon monoxide warning device triggered an alarm and the CO level in the ambient air was massively increased. “This measurement means an imminent danger to the life of anyone who is in the relevant area,” the fire department emphasized on Saturday. A participant alerted the emergency services because her friend had collapsed.

Around 50 to 100 people were celebrating in the premises when the fire brigade arrived. The emergency services ordered the immediate evacuation and called in further reinforcements from the fire and rescue services. All of the revelers were medically examined on Saturday, and several complained of headaches, malaise and dizziness. Carbon monoxide measurements revealed “relevant” carbon monoxide poisoning in 18 people; one affected person required special treatment in a pressure chamber.

The fire brigade initially assumed that some revelers had fled into the surrounding area shortly before the public order office and police intervened and might need treatment. A search began with foot troops and a drone with a thermal imaging camera. However, the emergency services found no other affected people. 60 emergency services and 21 vehicles were deployed during the night-time operation.

According to the police, the event was not reported to the public order office. It is also unclear who is responsible for the fact that a generator was operated during the party – the suspected cause of the carbon monoxide poisoning. According to the fire department, if these are left untreated, they can lead to permanent brain and nerve damage and cause short-term seizures or impaired consciousness.