Free USB HDD Secure Format Tool?

[thumper]

Hi all,
I'm hoping someone can point me in the direction of some free software which will securely format a USB HDD, rather than delete particular files on it. I don't think DBAN supports external usb devices & the free version of KillDisk only seems to overwrite once.

Any advice or experience much appreciated.

Thanks
D

 

[eXor]

http://www.heidi.ie/eraser/

 

[bledd]

hdcleaner can do multiple vipes on empty space