Another iPhone 4 has exploded, this time in Brazil.

An iPhone plugged in to charge overnight began emitting smoke and sparks, according to the Brazilian iPhone blog, Blog Do iPhone.

Ayla Paulo Mota, the iPhone's owner was asleep next to the phone at the time, and the sparking occurred just centimetres from her face.

She told the TechTudo blog in Portugese, translated into English using Google Translate: "At dawn, I woke up seconds before witnessing the burning of my iPhone when I saw a lot of sparks and black smoke out of the cell. My room was full with an unbearable smell of smoke! At that moment, I turned off the power switch in the room to remove the phone from the outlet."

"I was not hurt, but it was 15cm from my eyes," she said.

Mashable writes that in 2009 a French teenager claimed to have been hit in the eye with a glass splinter from the exploding screen of an iPhone.

Earlier this week, an iPhone 4S caused a mid-air panic on an Australian flight, when a phone began to emit smoke and a red glow.

That phone has been handed over to the Australian Transport Safety Bureau (ATSB) and has been reported to the Civil Aviation Safety Authority (CASA) in that country.

The Australian reports that CASA has previously spoken of concerns about problems with lithium-ion batteries on flights.

Lithium batteries are a known safety problem during flight, and are listed as a dangerous good by the International Air Transport Association.