An iPhone battery overheated at an Apple store on Zurich’s Bahnhofstrasse on Tuesday, injuring a repairman and causing the temporary evacuation of 50 people from the premises.

According to Zurich City police, the device suddenly exploded for an unknown reason as it was being removed by a repair worker on Tuesday, burning his hand slightly. Seven other people received medical attention but were not hospitalised.

The smoking battery prompted the evacuation of around 50 customers and staff from the shop.

“The staff responded well and correctly. They sprinkled quartz sand over the overheated battery so that the smoke could be contained and sucked out after switching on the ventilation,” a police statement said.

Forensic specialists were examining what caused the incident, police said.