We use 9840 cartridges manufactured by Imation, similar to IBM 3590 tapes.
For our company, Imation will replace the cartridges that are defective as a
result of Imation processing; on average, this was true for half of the
cartridges that failed.  The only sticking point is that we must send the
cartridges to Imation for analysis.  If we magnetically erase the cartridges
to prevent live data from going out of house, we destroy the imprinted servo
tracks and void the warranty.  Our auditors decided that the risk of
exposing privacy data was too great, and instructed us to stop sending live
data to Imation.  We could send tapes to Imation if we wrote ones and zeros
across the entire tape, but if we are unable to write to the tape, then we
erase and dispose of the tape.  One additional note on disposal:  the tapes
contain chromium, a carcinogenic heavy metal that must be disposed of as
hazardous waste in the United States.

Doug