The employee was on a business trip when the computer went missing, The (New Orleans) Times-Picayune reported.
BP spokesman Curtis Thomas said the password-protected laptop had personal information -- including names, addresses and Social Security numbers -- on Louisiana residents who filed damage claims for last year's Deepwater Horizon spill before the process was taken over by the Gulf Coast Claims Facility.
"We don't think there's evidence that the laptop or data was targeted, or that any of the affected individuals have had their personal data compromised as a result of this incident," Thomas said Tuesday.
He said there is no need for anyone to refile claims because of the incident.
BP has sent letters to each of the 13,000 residents affected offering a free subscription to a credit-monitoring service.
An investigation of the laptop's disappearance is continuing and BP will not identify the employee who was using it.