A day after Lenovo Group's Sept. 28 notebook battery pack recall announcement—it will recall more than 500,000 Sony-cell-based battery packs used in its ThinkPad notebooks—Dell and Toshiba each said on Sept. 29 that they will also recall Sony-made batteries.

On Sept. 29, Toshiba announced that it will start a battery exchange program for approximately 830,000 Sony battery packs that were made for its notebooks, a company spokesman told eWEEK.

While Toshiba, based in Irvine, Calif., has not experienced any problems associated with the faulty Sony batteries so far, Eric Paulsen, the company spokesman, said the company decided to start the exchange program after Sony announced it would begin a worldwide global recall program.

Toshiba is not yet offering a list of specific notebook models that may have used the Sony battery packs. Paulsen said the company will keep its users informed through its Web site.

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On a statement posted on its Web site, Round-Rock, Texas-based Dell said it will recall an additional 100,000 Sony-based battery packs used in its notebooks. That number brings the total amount of battery packs the company has been forced to recall to 4.2 million.

The latest announcements by Dell, Toshiba and Lenovo, coupled by an additional 1.8 million tainted batteries used in some Apple Computer notebooks, bring the total Sony recall to more than 7.3 million battery packs worldwide.

Given that failures with the battery cells appear to be fairly rare—Dell, Apple and Lenovo reported having seen fewer than 30 incident of problems for their combined 6.5 million shipments—the companies say they are erring on the side of caution. Lenovo issued its recall after a single incident.

Click here to read the complete details about battery pack recalls for Lenovo's ThinkPad notebooks.

Dell was the first company to announce a recall, announcing on Aug. 15 that it is recalling 4.1 million notebooks that used Sony lithium-ion battery packs. Apple followed a few weeks later, and Lenovo announced Sept. 28 that it will ask users to change batteries in certain ThinkPad models.

All four companies affected by the recall have said the batteries will be replaced for free, with Sony shouldering most of the financial burden.

On the same day that Lenovo announced its recall with the U.S. Consumer Products Safety Commission, Sony issued a statement that it will begin a global battery recall.

"We believe that this program is in the best interest of both our customers and all consumers," the company said in its statement. Details of the plan were not released, and a CPSC spokesman said the federal agency will have no comment until the program is formalized.

What is Dell doing to help customers with its battery recall? Click here to find out.

The battery cells themselves, which are usually arranged in groups of six inside a battery pack, are at the heart of the problem. Metal particles introduced during manufacturing could cause a short circuit inside one of the cells, which can lead to a fire.

Before the recall was announced, several people reported that their laptops had caught fire. The latest happened earlier this month, when a ThinkPad T43 model notebook caught fire at Los Angeles International Airport.

Despite the fact that more than 7 million batteries have been recalled, many analysts have said the effect on the white-hot notebook market has been hard to gauge one way or another.

Thus far, relatively few users of Dell and Apple notebooks have come forward to have their notebook batteries replaced, analysts said.

Given that the recalls were widely publicized, the response thus far could signal a lack of worry among customers, one industry watcher said.

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