Apple started an exchange program for iPhone USB power adapters that "may overheat and pose a safety risk."
The affected models are the European USB power adapters supplied with the iPhone 3GS, iPhone 4 and iPhone 4S, shipped between Oct. 2009 and Sept. 2012 in 37 countries, the company said Friday. They were also sold separately as accessories, it said.
Those adapters may overheat in rare cases, Apple said, prompting it to offer to exchange affected power adapters for new, redesigned ones free of charge at Apple retail stores or authorized service providers. An Apple spokeswoman declined to comment on how Apple determined that the adapters posed a safety risk.
The adapters concerned are printed with the words "Model A1300" just above the right-hand power prong, with the "CE" safety approval logo in solid gray between the prongs.
Apple plans to replace the adapters with the redesigned Model A1400, on which the letters "CE" are outlined instead of filled.
"If you have an affected adapter, discontinue use and exchange it for a new one," Apple advised, adding that in the meantime affected iPhone owners can charge their device by connecting the USB cable to a computer. People who bought a replacement power adapter due to this issue can contact Apple about a refund.
Apple said it needs to verify an iPhone serial number before the adapter can be exchanged. However, the Apple spokeswoman could not immediately say why this is necessary.
Under an earlier exchange program, in which Apple collected counterfeit USB power adapters and offered discounts on the purchase of genuine Apple adapters, it recorded iPhone serial numbers to ensure that participants could only obtain the discount once. The latest serial number requirement could be a way to prevent people from "laundering" fake or second hand Model 1300 adapters into brand-new Model 1400 adapters for resale.
This is not the first time Apple has taken back its own power adapters for safety reasons. In 2008, the company recalled USB adapters supplied with the iPhone 3G in North America because the adapter's metal prongs could break of and remain in a power outlet, creating a risk of electric shock.
Loek is Amsterdam Correspondent and covers online privacy, intellectual property, open-source and online payment issues for the IDG News Service. Follow him on Twitter at @loekessers or email tips and comments to firstname.lastname@example.org