The recall was announced by the U.S. Consumer Product Safety Commission and follows a similar recall of 4.1 million Sony-manufactured batteries used in Dell laptops announced last week. Dell and the CPSC had reported six known instances of battery problems in Dell computers, including some well-documented occurrences of fires associated with the batteries and computers.
The CPSC said Apple has received nine reports of batteries overheating, including two reports of minor burns from handling overheated computers and other reports of minor property damage. There have been no serious injuries reported, according to the CPSC.
The recalled Apple notebook batteries were sold from October 2003 through August 2006.
Sony manufactures lithium-ion batteries used in laptops from Apple, Dell, Hewlett-Packard, and Lenovo, as well as in devices such as MP3 and DVD players.
In most cases, problems in the batteries were the result of a simple short circuit, a Sony spokesman told InformationWeek last week. "There are other factors that can lead to the rare instance of flaming. The odds are greater if the particles [inside the battery cells] move at a faster speed and are affected by things like charging and voltage," he said.
Nancy Nord, acting chairman of the CPSC, said on PBS's The News Hour recently that the issue "was not a design problem...but deals with quality control in the manufacture of the battery. A contaminant got into the cell, and when the battery is vigorously jostled or compressed, that contaminant can cause a short."
Nord said last week that the commission was investigating other products that use the Sony-manufactured batteries to see if similar problems might exist.