“You have got to be kidding” is what I really wanted to shout when a homeowner recently called to inquire about the appropriateness of a restoration contractor using an ozone generator to mitigate a pesticide spill in her small home. Do these purported professional mitigators not know that ozone is a respiratory irritant, and can react with some other chemicals to create toxic intermediaries? I struggled to control my rage as the elderly caller further described her symptoms of difficulty breathing, sore throat, heavy chest, and irritated eyes that developed while she occupied the home during the ozone “treatment”. To avoid frightening her, I calmed myself down and recommended that she see an occupational and environmental physician.
The lady called back and requested testing of her house, as the doctor had recommended she leave the homeuntil clean-up could be performed and verified. She reported that the doctor diagnosed her with a chemical on-set asthma. Her recovery would require clean indoor air. The doctor’s prognosis was that she would recover from the acute asthma, but long-term sensitivities that would require avoidance of environmental toxins.
Since several months had passed since the ozone was generated, I did not anticipate finding ozone when I tested the air. Based on the sweet solvent type odors that remained in the house, I expected to find chemicals that were breakdown products of ozone and carrier compounds that would be typical in aerosol pesticides. However, although the results verified that a chemical “soup” remained in the air, only a few compounds were consistent with ozone oxidation of solvents.
The primary ingredients in the chemical soup were paint-related products in concentrations that exceeded recommended residential concentrations more than three-fold. Since no painting had been done in the home for many years, the only conclusion that could be derived from the results was that solvent-based cleaners had been used in addition to the ozone. My client confirmed that the contractor did use some chemicals for cleaning after the ozone was ineffective. Since the chemical fingerprint was similar in various rooms of the home, but was higher in the room with the spill, I was quite concerned that porous furnishings, clothing, and bedding had adsorbed the chemicals. If this issue was not addressed, cycles of off-gassing and re-absorption could continue for years.
The ultimate clean-up of the home will entail a combination of forced off-gassing with heat, ventilation, and carbon-based filtration. To comply with the doctor’s request for clean-up verification, the project could be costly, as testing will likely be required at various phases. The ultimate test of remediation efficiency will be the ability of the homeowner to re-occupy without adverse health complaints. However, ethically, we must confirm that the targeted chemicals are non-detectable before allowing the client to use the “canary test”.
The costs associated with alternative living expenses, clean-up, and repeated testing could have been avoided if the contractor would have consulted with a qualified industrial hygienist or indoor air quality scientist prior to generating ozone. More importantly, appropriate consultation would have prevented the client’s adverse health effects. This case not only illustrates the importance of contractors practicing only within their areas of expertise, but also underscores the importance of consumer education regarding environmental toxins and contractor qualifications.
Additional ozone information http://www.epa.gov/iaq/pubs/ozonegen.html