It’s a tough time for Apple Store staff across the world, not only because iPhone owners rush to change their worn-out batteries as part of the $29 discount program, but also due to some batteries actually catching fire right when being serviced.

It happened earlier this week in Zurich, when an iPhone battery started emitting smoke all of a sudden, and now the same thing took place in Spain at Apple’s store in Valencia.

A report from local newspaper LasProvincias reveals that the iPhone battery hasn’t just emitted smoke, but it actually exploded, leading to the entire floor being filled with smoke.

This obviously triggered the store evacuation given the risks of smoke intoxication, and firefighters and police rushed to the scene. Emergency services, however, weren’t required to intervene because Apple Store staff managed to vent the building by opening all windows and to cover the faulty battery with sand. No injuries were caused to Apple employees or store visitors.

The Zurich incident

Apple hasn’t obviously released a statement on the incident, and it’s unknown at this point what iPhone model was equipped with the faulty battery and why exactly it exploded when being serviced.

On the other hand, in the case of the Zurich incident, the battery didn’t explode, but only emitted smoke inside the store, and paradoxically caused injuries to no less than seven people.

One Apple Store worker suffered minor burns when trying to smother the battery with sand, while other six persons were intoxicated with smoke and received medical care on the spot.

Apple is currently offering a major discount for replacing worn-out iPhone batteries, cutting the price from $79 to $29 after admitting to slowing down older devices in an attempt to prevent unexpected shutdowns. The program is available until the end of the year, but a substantial number of iPhone owners want to do this as soon as possible, which in return caused a battery shortage in the majority of stores.