They are probably safe. At least Erase is but result is not guaranteed if you are using filesystem caches or data is written to different location. Anyway:
Q. How does Erase 'erase' a file?
A. When erasing a file the following steps are taken:
1. The files protection flags are set to RWED
2. The files comment is cleared
3. The ownership information (if using mufs) is cleared
4. The file creation date is cleared
5. The file is overwritten 'TIMES' times with data (data is actually
different each time, ascii codes TIMES..0)
6. The file size is set to 0
7. The file is deleted as normal
