What does "DOE compliant" mean in Disk Utility? When erasing a drive with Disk Utility, you have a couple options. An insecure wipe, a single pass of zeroes, a "DOE-compliant" 3 pass, and a DOD (Department of Defense) 7 pass. 

DOE doesn't stand for Department of Energy, does it? That sounds silly.
DOE is a method to wipe disks, developed by Department of Energy as part in their manual to ensure the confidentiality of Department of Energy information.

From macs.about.com :


  When Disk Utility uses the DOE-compliant 3-pass secure erase, it will write two passes of random data and then a single pass of a known data pattern. This will take anywhere from a day to a week or more, depending on the size of the drive. You can run this stress test in the background while you use your Mac for other activities.