This editorial (re the 1993 Midwest flood) is reprinted from ACTS FACTS, v. 7 #8, August 1993, p. 3-4. Monona Rossol, Editor, 181 Thompson St., #23, New York, NY 10012.
Flood water hazards. When the rivers finally recede, many historic buildings, books, paintings, and other artifacts will need repair. They must be cleaned of flood water residues which can be contaminated with human and animal wastes, disease organisms, fertilizers and pesticides, gasoline and fuel oils, and much more.
Artifacts and interior decor also may be contaminated by chemicals within the building in which they were housed. Water rising through boiler rooms may carry fuel oil, antioxidants, and air conditioning chemicals. Flood water in homes can contain household chemicals such as moth repellents, drain cleaners, paint solvent, and bleach. The artifact itself also may be hazardous (e.g. coated with damaged lead paint, metal corrosion, etc.). Conservators and restorers must consider all these hazards and select gloves and other protective equipment depending on the size and hazards of the job.
Molds and fungi also will be growing in damp indoor sites. Repeated or massive exposures to these microorganisms can sensitize some individuals, creating lifelong allergy problems. Some microorganisms also are toxic in large quantities. Combatting them requires ventilation which provides fresh air, humidity and temperature control.
If ventilation cannot be provided, or if the workplace has a moldy odor, shows evidence of infestation, or workers develop symptoms, air sampling should be done. In 1986, the ACGIH Committee on Bioaerosols proposed that "total counts exceeding 10,000 cfu/m3 [colony forming units per cubic meter] indicate a need to proceed to remedial actions" and that the presence of "any one fungus in levels exceeding 500 cfu/m3 can lead to a presumption of a building-related source."
Currently, the ACGIH recommends the use of rank-order comparisons of indoor and outdoor air sample populations, rather than specifying thresholds. This is not very helpful in flood areas since outdoor concentrations also may be quite high. Instead, the 1986 guidelines can be used as benchmarks for decisions about respiratory protection (although many people may not be able to tolerate molds at these levels). Consult an industrial hygienist for advice and to test air for molds and other toxic substances on site.
A NIOSH-approved toxic dust mask is probably sufficient for moderate mold concentrations. For higher concentrations, use a cartridge respirator with toxic dust filters. It is even conceivable that air-supplied respirators would be needed in some situations. Heavy infestations on building surfaces or on artifacts may manifest as colored (black, tan, pink, etc.) blooms. These should be swab-sampled and identified if people are having severe symptoms and to plan effective conservation (e.g. removing stains).
People already allergic to molds and fungi may not find any level of respiratory protection sufficient. And people with heart and lung problems, or pregnant women, may not be able to use respirators safely. Check with your doctor first.
These are only some of the health factors which must be considered. ACTS has additional information on request and will be happy to discuss difficult jobs with conservators and restorers, as we did after the Florida and Hawaii hurricanes.