A group of fourteen people in total arrived at the indoor hall in the town’s Boländerna district for an evening of go-karting followed by a Christmas buffet.
But after the first heat on the track, several of the participants found they were suffering from heart palpitations and nausea.
“We thought it was caused by the adrenaline kick from driving. But when one guy suddenly felt so bad that he had to lie down on the floor, we understood that something wasn’t right.
“Shortly after that, somebody else collapsed in the showers,” one of the participants, Stefan Berggren, told local newspaper Upsala Nya Tidning.
An ambulance was sent for and two of the go-kart drivers were taken to hospital. By the time the police arrived, Berggren himself was feeling so bad that he asked the officers to take him to the hospital too.
“We had fume levels in our bodies that brought us close to the point where organs begin to fail, according to the doctor,” said Berggren.
“Those of us who came to the hospital realized how serous it was. The ones who remained in the hall went home later in the evening, but a lot of them were in really bad shape.”
Police in the town are now investigating the incident, which is being classified as a possible case of negligence leading to bodily harm.
Thomas Appelquist, from Nordic gokart & events in Uppsala, said the company had decided this week to install a system that would relay a warning if carbon monoxide levels became too high.
“We are taking what has happened very seriously. The ventilation system probably suffered a minor collapse. Staff didn’t notice it as quickly as the customers,” Appelquist told Upsala Nya Tidning.