The widespread process of erasing data storage tapes and "recertifying" them for sale isn't safe and could cause enterprises to expose sensitive business data, a major tape vendor said yesterday.

Imation, which makes tape cartridges and other storage media, says there's no way to completely erase the data that has been recorded on computer tape.

"Today's tape cartridges have storage capacities of 500 gigabytes or more. Even if 99.9 percent of data is erased from a tape, hundreds of megabytes of potentially sensitive data could remain on the tape," says Subodh Kulkarni, vice president of global commercial business, R&D, and manufacturing at Imation. "This could include thousands of customer names and Social Security numbers."

To prove its point, Imation purchased 100 recertified tapes from mainstream channels and scoped each one to see what data it could find. According to its report, the company found sensitive data from a major U.S. bank -- including employee credit card records, computer user names, and server inventories. It also found detailed patient information from a major U.S. hospital, field research data from a scientific research center, and details on the Human Genome Project from a large university.

"In our lengthy testing and analysis, which has spanned many months, we have confirmed industry guidance that the only way to properly dispose of data is to destroy the media itself," Kulkarni says. "The technical truth is there is no practical and secure way to completely erase and 'recertify' most used tape products."

Imation's conclusions could certainly be seen as self-serving, since the company loses dollars to the recertified tape market every day. But other studies, including one published several years ago by Computer Technology Review, have arrived at similar conclusions. Several other tape storage vendors, including Maxell and FujiFilm, have published similar studies.

Graham Media, one of many vendors that sells recertified tapes, asserts that the risk of buying recycled media is negligible. "Any data that remains on the tape is not usable/readable, much in the same way that old unreadable data resides in every overwritten tape cartridge in every data center in the world," the company said in a written response to tape vendors' warnings about recertified media.