The Cupertino, Calif., computer maker is recalling the packs, shipped with certain of its 12-inch iBook G4, 12-inch and 15-inch PowerBook G4 notebooks and also sold as extras and replacements, citing a fire hazard.

The Aug. 24 Apple recall—which affects only the G4 notebooks and does not involve more recent MacBook and MacBook Pro models—comes just 10 days after Dell recalled 4.1 million Sony-made battery packs on Aug. 14 for the same problem.

The recalls by Apple and Dell rank as the two largest in consumer electronics product history, according to the U.S. Consumer Product Safety Commission. The recalls are due to the discovery of manufacturing defects inside the lithium-ion battery cells.

The cells could contain impurities—essentially small metal shards—introduced during manufacturing. If the shards come into contact with other parts of the battery, they can produce a short circuit, which leads to excessive heat and potentially a fire, Sony said in a statement.

"The key message for consumers is to stay focused on these two announcements," said Scott Wolfson, a spokesperson for the Consumer Product Safety Commission, in Washington. "We are in contact with our federal partners and we are talking to our partners in industry. We are looking at lithium battery safety to make sure we have the safest batteries in the marketplace."

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While relatively rare, the battery cell defects have lead to at least one notebook fire—a Dell notebook went up in smoke at a business conference in Japan, casting a shadow over notebook PCs as well as Sony itself.

Wolfson declined to comment on the possibility of future battery recalls involving Sony or another computer maker. However, Sony said in a statement that it does not anticipate any.

"Apparently there aren't any more planned recalls," said Richard Shim, an analyst at IDC, in San Mateo, Calif. "But the fact that you have Dell and Apple—two manufacturers that are known for quality products—recalling these batteries certainly raises the question, Are there more to come?"

PC makers such as Hewlett-Packard and Lenovo Group have thus far said they were not affected by the Sony battery cell problem.

Sony, in a statement, said it supports the recall by Apple. However, it also said it anticipates no further recalls of battery packs using these particular battery cells.

Apple, which is working with the U.S. Consumer Product Safety Commission on the recall, asked customers to stop using the recalled battery packs immediately. It suggested that customers remove the packs and operate the notebooks using AC power.

"We discovered that some Sony batteries in previous models of PowerPC-based iBooks and PowerBooks do not meet Apple's standards for safety and performance," the company said in a statement. "Our No. 1 priority is to recall and replace the affected batteries free of charge."

An Apple spokesperson said the company did not expect the recall, which involved 1.1 million packs sold in the United States and 700,000 sold elsewhere, to have an impact on its financials. Sony, for its part, has said it would pick up part of the tab for both Dell and now Apple's recalls.

Apple said it had received nine reports of batteries overheating. Two of those reports involved people receiving minor burns from handling overheated computers. No serious injuries were reported.

Meanwhile, Sony said in a statement that it has introduced safeguards into its battery manufacturing process to address the contamination problem seen by Apple and Dell and to provide a greater level of safety and security.

"We believe the issue has been addressed to the satisfaction of our customers," the statement said.

Those battery packs involved in the recall include the model numbers A1061, A1078 and A1079. Of those packs, those with serial numbers that begin with HQ441 through HQ507 and 3X446 through 3X510 are involved in the recall, the company said. The numbers are located on a label on the bottom of the battery.

The iBook and PowerBook G4 battery pack recall also came just a few days after a CPSC spokesperson said some faulty batteries shipped with the company's 15-inch MacBook Pro models were not a safety hazard.

Apple began an exchange program for those packs on July 31 after discovering that they did not meet its standards for performance. One person familiar with the matter said the batteries affected grew swollen and could no longer reach their electrical contacts.

No other Apple models were included in the July 31 exchange program.

Customers seeking more information on the Aug. 24 recall can contact Apple via its Web site or call (800) 275-2273, the company said in a statement.

Editor's note: This story was updated to include more details about the battery recalls and information from statements by Apple, the Consumer Product Safety Commission and Sony.

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