"Following incidents involving batteries used in AT&T U-verse network cabinets, the company is replacing 17,000 similar batteries, all manufactured by Avestor," writes an AT&T spokesman, in an e-mail to Light Reading. "Normally, we would work with a vendor to diagnose problems and develop solutions. We can't do that in this case because Avestor filed for bankruptcy in October 2006 and closed shortly thereafter. As a result, we have decided to move forward with the removal of all Avestor batteries as quickly as possible," the spokesman adds.

AT&T says it has no immediate guess as to how quickly it can replace all those batteries. The carrier also declined to speculate on the costs of such an endeavor.

A company spokesman does note, however, that AT&T stopped deploying Avestor batteries during the first quarter of 2007. The company announced a new battery supplier in July 2007.

Whatever the timing and cost, it won't be trivial, according to industry analyst Kermit Ross, principal of Millenium Marketing.

"It's no small task to change out the batteries in thousands of remote cabinets, especially when many of them are already powered up and handling working U-verse subscribers," Ross says. "It looks like a multimillion-dollar job, considering the cost of replacement batteries plus the labor to install them. They'll probably need to change the wiring to the batteries, too."

AT&T's troubles with Avestor surfaced in October 2006, when an equipment cabinet exploded in a suburban Houston neighborhood, startling homeowners and ripping out a sizable chunk of fencing from one elderly couple's yard.

In January 2007, another incident occurred just 20 miles away from the first one. This time the cabinet caught on fire, though that was quickly extinguished. However, the concerns about the safety of the batteries powering the cabinets kept growing.

Following the first two Houston incidents, AT&T hired a leading scientific consulting firm to investigate the cause of the October 2006 equipment cabinet explosion and the January 2007 equipment fire.

The consulting firm, Exponent, concluded that the problems were caused by manufacturing defects, that the battery's safety features and overall design were "sound," and "concluded that the risk of hazardous failures with this battery is as low, if not lower, than the risk with alternative batteries."

Light Reading requested a copy of the Exponent report from AT&T, but has not yet received one.