WASHINGTON — Consumers are being asked to return 526,000 laptop batteries made by Sony Corp. because they could catch fire, the latest in a record-setting recall involving nearly 7 million computers.

IBM Corp. and Lenovo Group, the world's third-largest computer maker, yesterday announced the recall of rechargeable, lithium-ion batteries purchased with ThinkPad computers. A laptop caught fire at Los Angeles International Airport this month.

It is the fourth recall in recent weeks involving Sony laptop batteries. In August, Dell asked customers to return 4.1 million batteries and Apple recalled 1.8 million batteries worldwide, warning that they could catch fire. Last week, Toshiba said it was recalling 340,000 laptop batteries because of a problem that caused the laptops to run out of power.

In all, it is largest electronic-related recall involving the Consumer Product Safety Commission. The agency said there have been only 47 reports of batteries catching fire.

"While the risk may be real, it is very small," said Julie Vallese, a commission spokeswoman.

Sony said it was working with the agency on a worldwide recall program for certain battery models and may involve additional recalls.

"We believe that this program is in the best interest of both our customers and all consumers," Sony said in a statement.

In the latest recall, Lenovo cited a potential risk after a report of a smoking laptop at the Los Angeles airport. The computer emitted sparks and had to be put out with a fire extinguisher.

IBM and Lenovo, a Chinese computer maker that bought IBM's personal computer division in 2005, chose to pursue a broader recall, the commission said.

The batteries believed to be at risk were sold between February 2005 and this month, separately or along with ThinkPad computers. About 168,500 of the 526,000 batteries were sold in the U.S.

Previously, Lenovo had received two reports of a battery overheating in Japan and the Netherlands, said Ray Gorman, a spokesman for the company, which is based in Research Triangle Park, N.C.

The commission said the overheating problem did not appear to be linked to the defects cited in the Apple and Dell cases.

In the previous cases, Sony said the batteries could catch fire in rare cases when microscopic metal particles came into contact with other parts of the battery cell, leading to a short circuit. Typically, a battery pack will power off when there is a short circuit; but occasionally the battery would catch fire instead.