If a windows system can access the tape drive with read and write access, Blancco File Eraser can also access and erase files stored in tape drive.
Note that tape drives are not as safe as normal drives and there is theoretical possibility that traces of old information remain on tape. An overwrite will create a good protection and especially if the tape drives are being reused in the same organization. For decommissioning of tapes with sensitive information we recommend using degaussing.
For more information, read this article.