Twenty-five people have been treated for burns in northern Switzerland after walking through hot coals as part of a team-building exercise.
13 of them were taken to hospital and treated for more serious injuries after the incident on Tuesday evening, rtv21.tv reports.
About 10 ambulances went to the private event around 18pm.
The group walked on a "bed" of coal that was several meters long and caused immediate injuries.
It is not yet clear if there were any problems with the placement of the coal or with the way the group walked through them.
Officials have opened an investigation and obtained evidence from the site, which is on the Au peninsula south of the city of Zurich.
Walking through a bed of hot coals, often known as walking with fire, is sometimes used in motivational courses and charity events.
It involves walking barefoot on hot embers or coals. It is also used in many parts of the world as a passing ritual or test.21Media