More than 30 people suffered carbon monoxide poisoning in a go-kart hall in Jena on Saturday. First, two karts collided, with one person being slightly injured, a police spokesman said. Dozens of people then complained of respiratory problems and headaches.

38 people were finally classified as slightly injured by the emergency doctor, as the police announced on Sunday night. Among the injured were five teenagers and eleven children.

Emergency services found an increased concentration of carbon monoxide in the hall, for which there was initially no explanation. The investigation is expected to continue on Monday. The kart track will remain closed until then, said a police spokesman. The "Ostthüringer Zeitung" had previously reported on the incident.

Carbon monoxide is an odorless, colorless and tasteless gas that is a potent respiratory poison in high concentrations. It forms when too little oxygen is available during combustion processes.