The U.S. Consumer Product Safety Commission has reviewed substandard batteries for Apple's 15-inch MacBook Pro notebooks but determined they didn't pose any safety threat, a commission spokesman told CRN Wednesday.

Apple has voluntarily launched an exchange program for batteries sold in some 15-inch MacBook Pro laptops, but the Cupertino, Calif., company said on its support Web site that it was doing so only because it discovered the batteries "do not meet our high standards for battery performance."

The batteries were sold between February and May, and Apple said that since there are no safety issues, the batteries could still be used until replacements arrive. Apple spokesmen didn't return calls for comment on the matter.

For several weeks before Apple began the voluntary exchange program, reports surfaced on several Web sites about "bulging" batteries in some MacBook Pro systems. The bulging was so severe in some instances that the notebook casing was bent out of shape.

CPSC spokesman Scott Wolfson declined to say whether Apple's voluntary exchange program arose in response to the bulging problem or whether the program stemmed from other battery issues. "We never allow a company to do an independent recall when there is a substantial potential hazard," Wolfson said.

Apple began the exchange program after asking customers who heard "a high-pitched buzzing sound" in their MacBook Pros to contact them.

The CPSC's Wolfson also declined to say if Sony was involved in the manufacturing of the MacBook Pro batteries in question, since a recent recall of 4.1 million notebook batteries by PC giant Dell involves Sony laptop batteries.

"We are looking at Sony batteries outside the scope of the Dell recall," Wolfson said. That includes trying to determine whether the manufacturing line involved in the defective Dell battery cells was used to make components for other notebook vendors. Those batteries are being blamed for several cases of severe overheating and pose a fire hazard, Dell and the CPSC have said.

Apple solution providers that CRN interviewed about the MacBook Pro battery issue said they hadn't received reports from customers about major defects or problems with batteries, though some minor, non-hazardous issues have emerged, such as batteries that fail to recharge properly.