Long-term monitoring of mold contamination in flooded homes

One consequence of the spring and summer floods of 1993 has been an enormous number of water damaged homes in the upper midwestern United States. A team of investigators with a variety of skills was assembled to monitor the effect of various cleaning, disinfecting, and drying strategies on indoor air quality of two flood damaged homes over one year's time. Additionally, six flooded homes in Marshall, Minnesota, were monitored twice, at seven and 17 months after flooding. One component of the home study was periodic measurement of indoor mold spore levels. Measurements in all homes indicated that elevated mold levels persisted long after homes were cleaned and dried. While ambient levels throughout the homes tended to return to normal after about a year, pockets of contamination remained at the end of the study. Although no comparable pre-flood data are available, these results suggest that more effective decontamination procedures may be needed to prevent subsequent mold problems in flood damaged homes.