25 people injured after walking barefoot on hot coals in a corporate team-building activity, reports say

• Employees of a Swiss marketing company walked over hot coals in a team-building activity.
• Twenty-five employees were injured, with 13 of them going to the hospital, according to reports.

A team-building exercise on a corporate away day in Switzerland went horribly wrong when 25 employees had to be treated for burns, according to reports.

The Zurich-based marketing agency Goldbach hosted some 150 employees on the Au peninsula on Lake Zurich, Switzerland, on Tuesday, the Swiss news outlet Blick reported.

Employees were invited to walk barefoot across several feet of hot coals as part of the team-building activity on Tuesday evening, according to Blick.

Police said that employees walked one after another over the hot coals and did not immediately feel pain from the burns, Blick reported.

But many complained of pain afterward, and at least ten ambulances were called to the scene, according to the New York Post.

Police described treating injured employees as a "major operation," according to the Swiss news website Klein Report.

Twenty-five employees were injured during the exercise, with 13 hospitalized for more severe injuries, per the New York Post.

Zurich officials attended the site to secure evidence and start an investigation into the circumstances of the accident, according to Klein Report. Police investigations are ongoing, the website reported.

Goldbach CEO Michi Frank confirmed in an internal memo that employees were injured after participating in the "voluntary" team-building activity, Klein Report noted.

"Appropriate preparation" took place before the walk, which, he said, should have been "basically unproblematic," according to Klein Report. He said he was sending his support and wishes for a speedy recovery, per the internal memo.

Insider reached out to Goldbach for comment on Friday afternoon but did not immediately receive a response.