The recall affects certain Inspiron, Latitude and Precision mobile workstations and XPS units shipped between April 2004 and July 18, 2006. Sony manufactured the batteries that are being recalled, the representative said.

If they have one of the affected units, consumers are advised to eject the battery from the notebook after powering down and continue using the notebook with its AC power adapter, the CPSC said. Dell has so far received six reports of overheating units that caused property damage, but no injuries.

Dell has faced ,

If they have one of the affected units, consumers are advised to eject the battery from the notebook after powering down and continue using the notebook with its AC power adapter, the CPSC said. Dell has so far received six reports of overheating units that caused property damage, but no injuries.

Dell has faced several issues this year related to exploding or flaming notebooks, and wants to ensure the safety of its customers, the representative said. The 4.1 million units is a subset of the 22 million units shipped during that time frame, he said. Dell said it doesn't expect the cost of the recall to materially affect its earnings. The company reports earnings for the previous quarter this Thursday.

At the moment, this looks like the largest battery recall in the history of the electronics industry, said Roger Kay, an analyst with Endpoint Technologies Associates. "The scale of it is phenomenal."

Sony will help pay the costs associated with the recall of 4.1 million batteries the company supplied to Dell, said Rick Clancy, a Sony spokesman.

"We are supporting Dell's recall," Clancy said. "There will be financial assistance and we are sharing engineering data and both doing further research." He declined to specify exactly how much assistance Sony would provide.

Customers will be able to go to a Dell Web site or to the Consumer Product Safety Commission site to determine if they need a new battery. Dell also plans to launch a toll-free number, 1-866-342-0011, for people affected by the situation, IDC analyst Richard Shim said.

"It's a huge deal," Shim said, particularly for Dell customers with employees in remote locations or traveling. "If you have people all over the field, then you're asking folks to send in the batteries and run off just AC (alternating current power) until they can get new batteries shipped out to them."

Dell had only six incidents over millions of units, Shim said, but it's "a dangerous situation."