Bill Liberty, president of the facility's National Air Traffic Controllers Association unit, said he was told on Monday by Eric Fox, Oberlin's air traffic control manager, that a computer hard drive with the personal information was stolen.
Fox declined to comment, referring calls to FAA spokeswoman Elizabeth Cory in Chicago.
Cory confirmed that personal information for more than 400 controllers was on the missing hard drive, but she declined to specify precisely what the information entailed.
"We believe the hard drive was encrypted so that any personal information that might have been on it would be protected," she said, adding that the incident is under investigation.
A computer technician discovered the loss on Friday when he opened the computer to install a new DVD drive, Liberty said. The missing data could be used to apply for credit cards or loans.
"We're still investigating to determine if it was stolen," Cory said of the hard drive. "It's possible someone removed it for some other purpose. We have sent out notices to all employees [about 700 at Oberlin] and alerted them."
Cory confirmed that to remove the hard drive someone would have to open a computer casing and unscrew and detach the device. She said someone may have removed the hard drive for a legitimate reason, but no one has come forward with that information.
"The computer was in our training center," Liberty said. "We do a lot of training involving military missions and procedures up there. I don't know if any of that information was on the hard drive."
Liberty said the training room is locked between 3 p.m. and 6 a.m. when not being used for training.
Cory said there was no indication that any national security information was on the hard drive.
"What training we may do is nothing security-sensitive," she said. "The procedures are published and available on the Internet."
Liberty said the controllers and others have to sign on with their names and Social Security numbers to gain access to the computer. He believes that information was what was sought.
"We were told to take precautions," Liberty said. "What does that mean? The FAA should at least provide us with identity-theft protection."
Liberty said investigators speculated someone stole the hard drive for spare parts. He's skeptical.
"Come on, this is a 10-year-old machine. The hard drive only holds 8 gigabytes," he said. "Who would risk their job for a $10 part?"