Q: I just read your reply concerning mold contamination and blueprints. I was involved in a similar situation. Initially a HEPA filter system was used to remove the airborne spores but this was only effective for the perimeter of the room. Every time someone retrieved an item from the room, it still had signs of mold contamination. We then switched to an active O3 system that kills mold, mildew and bacteria. This worked and did not damage the paper. Comments?

A: Certainly the presence of ozone will kill mold spores if it is presented at extremely high levels. Unfortunately, those levels need to be high, perhaps too high for human exposure. You can run the equipment in a confined room, but people should not be present without PPE (personal protective equipment).

Proper restoration of damaged materials such as blueprints will require that each and every piece of paper is touched. Every piece of paper needs to be physically inspected and reviewed to ensure that the damage caused by the presence of mold has not hurt the image. As such, simply flooding a room with ozone does not accomplish that. How would ozone reach the middle pages in a stack of 80 or 100 prints? And how could you gauge -– or control -– the amount of ozone presented to that page?

Unfortunately, killing a mold does not stop its ability to impact people. Extensive research by the ACGIH, ASHRAE, and many independent researchers on bioaerosols, has shown that molds that are producing mycotoxins MUST be removed in their entirety to ensure that personal risk is reduced. Simply killing a mold spore but not removing it increases the potential for exposure to occupants. It also increases the liability of those who claim the risk is gone, especially when there are large volumes of science showing that leaving mold in place, dead or alive, is dangerous.

Travis West is the president of Building Air Quality Inc., a Houston-based indoor air quality consulting firm. He can be reached at twest@baq1.com, or toll-free at 866-367-1177.

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