Sony executives were informed about a Dell notebook that caught fire in November last year, after its engineers were sent to have a look and reported the battery was prone to overheat because of the contamination with metal particles during the battery's production process, said a local (Japanese) newspaper, the Yomiuri Shimbun.

The electronics giant learned in December that a Dell notebook computer caught fire in November and it was fitted with one of Sony's batteries, said the same newspaper. Sony then concluded that the battery was prone to overheating and that the reason for the overheating was metal particles that had contaminated the battery during the production process.

The production process was corrected immediately upon discovering the problem, but Sony only examined the same type of batteries produced around the same time. Sony did not examine batteries it had produced for companies other than Dell on the ground that no accidents had been reported in other computers. Sony also did not thoroughly examine the electrical circuits and other hardware used in Dell PCs. The November incident was reported to other PC makers, telling them what the cause was and the fact that Dell had carried out a recall, but it did not request other makers to recall Sony batteries.

After other cases of fire involving Dell PCs were reported this summer, Sony examined its batteries again. "Due to the combination of PC hardware (in Dell Pcs), our batteries could start a fire. We concluded that no further problems were likely to occur at the time of Dell's December recall, but we failed to examine the hardware used in Dell Pcs", said a spokesman from Sony.

As for the reason Dell did not release the name of battery maker at the time of December recall, a spokesman from Dell's Japan unit said "basically, the names of suppliers are a corporate secret. We concluded it was a rare case as the number of PCs involved in the (initial) recall was small."

On Thursday, Sony announced a global replacement program for potentially hazardous batteries after major manufacturers of laptop computers equipped with Sony batteries announced a series of massive recalls. Sony will offer to replace certain battery packs for notebook computers in response to concerns over recent overheating incidents. Sony already faces multimillion-dollar losses from embarrassing recalls of its potentially hazardous lithium-ion computer batteries, reports The Inquirer.