A student loan insurance company breathed a sign of relief Friday when officials announced the recovery of safes containing more than 600 CDs worth of private personal information stolen in March.

3.3 million student borrowers nationwide whose personal information, including Social Security numbers, is stored on the CDs.

Minneapolis police found the data, approximately 650 CDs and floppy disks, on March 22, a few days after thieves stole property with personal student information, such as social security numbers, from Oakdale, Minn.-based Education Credit Management Corp., one of the nation’s top 10 guaranty agencies for student loans.

The Minneapolis Star Tribune reported that the recovered materials remained in police custody for weeks because officers didn’t know what they had recovered.

The thieves broke into the safes, but apparently didn’t access the encrypted data, according to a Minnesota Department of Public Safety media release sent Friday.

The company issued a statement sounding thanks to the authorities and assurance for clients whose information may have been compromised.

“We were very pleased to learn yesterday that the property and data stolen from ECMC headquarters have been recovered” said CEO and President Richard Boyle. “We remain vigilant to the needs and concerns of our borrowers, and continue to encourage borrowers who were notified by us of this incident to take advantage of the free credit monitoring and fraud protection package we are providing them through Experian.”