A laptop computer that was reported stolen from an Army employee's truck last week contained personal information on about 800 to 900 Fort Lewis soldiers, said military and Lacey police officials.
A post spokeswoman said officials were notifying the involved soldiers out of concern that the case might put them at risk for identity theft.
Officials said the employee, a civilian military personnel specialist, appears to have violated Army standards and policies for protecting personal information and government property.
The Army is assisting Lacey police with the theft investigation and conducting its own review, said Catherine Caruso, a Fort Lewis spokeswoman.
"We're not releasing anything more about what information was inappropriately compromised or about the soldiers whose information was involved," Caruso said.
"Clearly it was personal information regarding 800 to 900 soldiers from Fort Lewis. Beyond that, we'd rather not specify."
Federal agencies have stepped up their security requirements for personal information stored on laptops and portable hard drives in the wake of several high-profile laptop thefts within the past two years, notably at the Department of Veterans Affairs.
In May 2006, VA officials said a stolen laptop contained the Social Security numbers and other personal information of as many as 26 million veterans. It was later recovered and department officials said the information wasn't compromised.
In this case, an Army employee told Lacey police he left the laptop and a 500-gigabyte removable hard drive on the seat of his Dodge truck, parked unlocked in front of his house overnight July 3. He reported them stolen about 10 a.m. on July 4.
He told police there was no classified, secret or top-secret information on the laptop and the hard drive.
Lacey police redacted the man's name from a copy of the report it released Thursday. Fort Lewis declined to identify him pending the military's investigation.
Caruso said the employee was working on a project regarding a particular unit at a location other than his office.
She said "it would be inappropriate to speculate" about what potential disciplinary action the worker might face if he is found to have broken security rules.
She said the Army began no later than Wednesday notifying the affected soldiers through e-mail and phone calls. They'll get follow-up letters, she said.
Army laptops and removable storage devices containing personal information are generally restricted to on-post workplaces but can be signed out with a supervisor's permission. They're also supposed to be password-protected and personal information is supposed to be encrypted, Caruso said.
Since the theft, post officials have set new training requirements for military personnel staff and prepared a memo for each employee to sign outlining the safeguarding and reporting requirements, she said.