/sys$common/syshlp/helplib.hlb INITIALIZE, Qualifiers, /ERASE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /ERASE
       /NOERASE (default)

    Physically destroys deleted data by writing over it. Controls
    the data security erase (DSE) operation on the volume before
    initializing it. The /ERASE qualifier applies to Files-11 On-Disk
    Structure Level 2 and 5 disks and ANSI magnetic tape volumes,
    and is valid for magnetic tape devices that support the hardware
    erase function, such as TU78 and MSCP magnetic tapes.

    If you specify the /ERASE qualifier, a DSE operation is performed
    on the volume. For disk devices, the ERASE volume attribute is
    set. In effect, each file on the volume is erased when it is
    deleted.

    Note that the amount of time taken by the DSE operation depends
    on the volume size; the INITIALIZE/ERASE command is always slower
    than the INITIALIZE/NOERASE command.