WASHINGTON — Personal information on 26.5 million veterans that was stolen from a Veterans Affairs employee last month included not only Social Security numbers and birth dates but in many cases phone numbers and addresses, internal documents show.

Meanwhile, VA Secretary Jim Nicholson said Wednesday that he had named a former Arizona prosecutor as a special adviser for information security, a new three-month post that will pinpoint security problems at the VA and develop recommendations for improvements.

The three pages of memos by the VA, written by privacy officer Mark Whitney and distributed to high-level officials shortly after the May 3 burglary, offer new details on the scope of one of the nation's largest security breaches. The memos were obtained Wednesday by The Associated Press.

They show that a file containing 6,744 records pertaining to "mustard gas veterans" — or those who participated in chemical-testing programs during World War II — was breached, and that a "short file" with as many as 10 diagnostic codes indicating a veteran's disability also was stolen.

At the same time, however, the memos suggest that the data might be difficult to retrieve by thieves.

"Given the file format used to store the data, the data may not be easily accessible," stated one memo dated May 5 and distributed internally May 8.

A spokesman for the VA did not have immediate comment on the memos Wednesday.

Some lawmakers said Wednesday they were troubled by the new revelations, which go further than what the VA initially reported after publicizing the theft on May 22. At the time, Nicholson said the data were limited to names, Social Security numbers and birth dates; he later indicated that diagnostic codes in some cases also may have been breached.