Adding to the lengthening list of organizations reporting data compromises, the American Institute of Certified Public Accountants (AICPA) Wednesday confirmed that a computer hard drive containing the unencrypted names, addresses and Social Security numbers of nearly all of its 330,000 members has been missing since February.

The hard drive had been accidentally damaged by an AICPA employee and was sent out for repair to an external data-recovery service in violation of the AICPA's policies, said Joel Allegretti, a spokesman for the New York-based organization. It was on its way back to the AICPA via FedEx but failed to arrive. Allegretti did not say when exactly the drive went missing except to note that the package containing it was due back at the AICPA "towards the end of February."

It took the organization until March 31 to "recreate the drive" and determine what data it contained. The AICPA began notifying affected members of the potential compromise of their personal data on May 8 and has since completed the task, Allegretti said.

Jim McClusky, a spokesman for FedEx, said it is unclear what exactly happened to the drive. But he stressed that it is a mistake to characterize the package as being lost.

"We did handle the shipment, and we are working closely and cooperatively with our customer to determine where the package might be," he said. "It is still being investigated. At this point, we are looking at it as a missing shipment; that doesn't mean it's lost."

Based on investigations so far, it does not appear that information on the hard drive has been misused, Allegretti said.

Following the loss, the AICPA is offering affected members a year's worth of free credit-monitoring services. The incident has also prompted the group to begin deleting all Social Security numbers from its member database.

While a note posted on the organization's Web site says the collection of Social Security numbers has been a long-standing procedure, it added that "we will cease collecting and maintaining them, except in limited circumstances. And even for those, we are accelerating our efforts to develop other means of uniquely identifying our members."

News of the AICPA breach comes amid a flurry of similar disclosures in recent days. By far, the biggest was the May 22 disclosure by the U.S. Department of Veterans Affairs that it had lost personal data on more than 26.5 million veterans discharged since 1975. Since then, the agency has admitted that the breach may have exposed personal information on about 2.2 million active-duty National Guard and Reserve troops as well.

Since then, there have been similar disclosures elsewhere, including Texas Guaranteed Student Loan Corp, a nonprofit organization. TG said that an outside contractor lost an unspecified piece of equipment containing the names and Social Security numbers of approximately 1.3 million borrowers.