This note was sent by the author last December to Gerald D. Gibson of the Library of Congress, who passed it on to the Abbey Newsletter. It is published here with the author's permission.
As a magnetic tape decontamination and restoration facility, we frequently deal with mold on tapes. We have a few hundred such tapes in-house right now. Experience dictates that the most important thing you must do right away is damage control.
First, determine if the mold colonies are active or dormant. The easiest way to do this is to gently wipe the visible mold with a soft, non-dusting tissue or with your finger after putting on protective latex gloves. Wipe with the wind to avoid causing edge damage. If the mold is dry and dusty, the colony is probably dormant. If the mold smears, you have an active colony and must take immediate steps to drive the mold into dormancy. Active colonies will continue to damage the tape. In addition, attempting to decontaminate tapes with active colonies introduces complications and added risks.
Most mold will go dormant below 70% RH but some mold can remain active as low as 50% RH. Also remember that the tape itself will have absorbed some moisture. Even if the air is at or below 50% RH, the mold can remain active as long as the tape retains enough moisture.
Isolate the affected tapes to avoid contamination of your other materials. Make sure the environment in which they are stored has a low humidity to remove the moisture and to drive the mold into dormancy. Personnel handling the affected tapes should always wear gloves and masks to protect against spreading or inhaling spores.
There are a number of methods of cleaning tapes that remove the "flowering heads." Cleaning does not, however, kill the mold. To actually kill the mold requires chemical decontamination. We do not recommend attempting to perform either the cleaning or decontamination in-house. The procedures involved are delicate and may pose a health hazard to personnel: it is best to have the work done by an experienced professional. As indicated before, this is a service we provide. SPECS BROS. has been cleaning and decontaminating tape since 1983 and we have processed over 250,000 tapes, many of which have had mold problems.
If you would like additional information, advice or help, give us a call or send us an e-mail. You might also be interested in taking a look at our website (www.specsbros.com), which offers tips on restoration, disaster planning and recovery.Peter Brothers