A STUDY RELEASED IN MAY BY THE INSTITUTE of Medicine, an independent branch of the National Academy of Sciences that advises the federal government on health issues, concluded that most health concerns surrounding the spread of mold in homes are unfounded. A panel of epidemiologists, toxicologists, and pediatricians could not link most molds to cancer, fatigue, reproductive health problems, or brain damage. But the panelists did acknowledge that toxic mold could be tied to upper respiratory problems in some cases, especially where building conditions are damp.

People with asthma are the most susceptible to mold, but even completely healthy people may develop mild respiratory symptoms if they are exposed, the study found. But some panelists said that even then, they were unsure that there was a conclusive connection between mold and asthma-like problems. “We know that when people are in damp spaces, they report more upper respiratory tract problems and asthma symptoms,” said Dr. Noreen Clark, dean of the School of Public Health at the University of Michigan, who chaired the panel. “But we don't know that mold is the cause, because dampness is associated with dust mites [and] bacteria,” she said.

The panel based its conclusions on a review of hundreds of scientific papers, but also encouraged more studies in the area. Meanwhile, homeowners, builders, architects, and developers should focus on designing buildings that stay as dry as possible, the panel recommended.

Insurers paid out $2.5 billion in 2002 in mold-related lawsuits, and the suits are not dying out. The panel's findings were immediately attacked by homeowners' associations. Melinda Ballard, an Austin, Texas, homeowner who filed one of the first mold-related lawsuits, stood by her belief that breathing in mycotoxins, a common byproduct of water damage, had caused her family severe illness.