The U.S. Federal Trade Commission is urging the photocopier industry to address privacy risks arising from the fact that digital copiers store thousands of documents on their internal hard drives.Also see: Is your office printer secure?CBS News reported in mid-April that nearly every copier built since 2002 stores images of documents that pass through the machines. The report found sensitive health and law-enforcement information on copiers ready to be resold.In a recent letter to Rep. Ed Markey (D-Mass.), FTC Chairman Jon Leibowitz said the agency is examining whether copier makers and resellers are warning their customers about the privacy risks, providing educational materials and offering "options for secure copying."Markey, who requested an FTC investigation, called the hard drives a "treasure trove" for identity thieves, who could obtain Social Security numbers, birth certificates, medical records and bank records.Xerox Corp. offers customers the option of removing the hard drives from copiers that they are about to dispose of or turn in after a lease, a company spokesman said. The copy machine maker also offers a free image-overwrite option that destroys information stored on many models' hard drives, he said.