NEW YORK (CNN/Money) - Bank of America said Friday it lost computer tapes containing account information on 1.2 million federal employee credit cards, among them those of U.S. senators, potentially exposing them to theft or hacking.

The bank told CNN/Money that federal government's General Services Administration (GSA) cardholders' account information may have been on the tapes.

The tapes were lost in December, but a bank spokeswoman told Reuters that bank officials were not allowed to notify cardholders until they received permission from federal law enforcement authorities

The missing tapes may contain information, including cardholders' names, addresses and social security numbers. But it varies from account to account.

According to Time.com, which cited an unnamed U.S. official, a large percentage of the accounts are for the Pentagon, in addition to 40 federal agencies and other entities.

Sen. Charles Schumer, a New York Democrat, told Reuters that he had been informed by the Senate Rules Committee that the data tapes were likely stolen off a commercial plane by baggage handlers.

"Whether it is identity theft, terrorism or other theft, in this new and complicated world baggage handlers should have background checks and more care should be taken for who is hired for these increasingly sensitive positions," he added.

Bank of America declined to reveal how many GSA accounts they handle but a spokeswoman said federal law enforcement is investigating the loss.

The financial giant said it has sent out a letter to inform its GSA cardholders whose information may have been on the tapes.

"So far no evidence to suggest the tapes have been accessed or misused," said Eloise Hale, spokeswoman for Bank of America. "The tapes are now presumed lost."

Bank of America (Research), based in Charlotte, North Carolina, said it will continue to monitor government cardholder accounts included on the data tapes and cardholders would be contacted if unusual activity is detected.

GSA charge cardholders with questions or concerns may contact the bank at the following toll-free number -- 800-493-8444.

"We deeply regret this unfortunate incident," Barbara Desoer, who is in charge of technology, service and fulfillment for the Charlotte-based bank, said in a statement. "The privacy of customer information receives the highest priority at Bank of America, and we take our responsibilities for safeguarding it very seriously."