Ozone "blasting" of mold is rapidly gaining popularity, although it remains controversial. This heavy, commercially applied blast of ozone into a home for several hours is not to be confused with "ozone generators" sold on infomercials, said to cure everything from cancer to athlete's foot.  This has certainly given the entire industry a bad reputation.

Household ozone generators have been universally scorned by some experts, including the Environmental Protection Agency.

More expensive ozone generators that lack the safeguards (and operator training) for safe monitoring of ozone levels can be cranked up to produce health-damaging amounts of ozone. If the level of ozone produced by these machines is low enough to meet safety standards, it will be wholly ineffective killing organisms of any kind.

But fire up a monitored commercial rig with people out of the way, and everything in its path will die: rodents, insects, germs, bacteria, viruses, mold and odors. Human tissue exposed for a prolonged period can suffer heavy damage. The area is basically sterilized, as if someone dropped a biological neutron bomb.

During commercial treatment, the home is temporarily vacated, sealed, and filled with relatively high levels of ozone. After treatment, the home is ventilated with purging fans and the ozone levels brought to acceptable levels before free-breathing humans and pets can re-enter. And it's relatively inexpensive.

Sounds almost too good to be true? Well, some public-health organizations, indoor-air-quality specialists, and industrial hygienists think it is and do not recommend ozone treatment for mold. However, in the right concentration levels it can be very effective and not harmful. Ozone blasting — as well as cleaning with soap and water or some antimicrobials that are put out by unscrupulous entrepreneurs that have no laboratory proof to back up their effectiveness claims— is just not effective on mold entrenched deep inside soggy building materials. Current technology is limited: Ozone can only kill where the air can physically circulate, limiting it to exposed interior walls and surfaces. Physical removal of the affected building materials is sometimes necessary.

Tom Beardslee, an ozone remediation contractor/applicator tells his clients to vacuum thoroughly with a HEPA vacuum after ozone treatment. (Beyond debating the ozone's effectiveness and kill ratio, many hygienists would insist that more than a simple vacuuming is needed to eliminate possibly mycotoxins.) However, Beardslee predicts technology will eventually allow ozone to be placed in previously inaccessible locations, eliminating much of the need for costly repairs to drywall and other surfaces that are removed to provide access for cleaning.

And a final caution: Be sure to seal off ozone-treated areas from the rest of the house, thoroughly vacuum with a HEPA vacuum and an air-filtration system, and wipe all surfaces with soap and water.

These ozone producing air purifiers that are on the market can be very effective as most of the ozone levels that they put out are safe, despite the bad press some of them have received lately.  Combined with UV light, these machines can be very helpful for destroying airborne spores and mycotoxins.  When ozone was first introduced there were some companies that marketed these machines making many false claims, such as the ability to kill mold and "remediate" mold problems.  There is no way that a commercial machine such as this could perform such tasks and the companies who made these claims were rightfully sued.  Presently, an ozone air purifier is capable of purifying the air and no company who markets these machines should claim to do anymore than this.