safe to delete file from Time Machine hard drive?

Is it safe to delete a file from an external hard drive that's being used for Time Machine backups? The file is not a backup -- it's a .dmg from the manufacturer of the hard drive. Other than that one file, I don't use the drive for anything other than Time Machine.

I'm just concerned because I don't want deleting the file to affect Time Machine in any way.

Thank you.