Mold and dampness can cause coughing and wheezing, but there is no evidence linking them to cancer, debilitating fatigue or neurological problems, experts said Tuesday in a report by the National Academy of Sciences.
“Even though the available evidence does not link mold or other factors associated with building moisture to all the serious health problems that some attribute to them, excessive indoor dampness is a widespread problem that warrants action at the local, state and national levels,” Noreen Clark, dean of the School of Public Health at the University of Michigan, said in a statement accompanying the report.
Clark headed an Institute of Medicine panel that studied the health effects of mold, which has drawn increased attention in recent years with the shutdown of a major hotel, delayed openings of schools in several states and a raft of lawsuits.
Where sufficient evidence exists
The Institute, an arm of the National Academy of Sciences, said mold and building dampness do constitute a problem and urged it be corrected through a range of steps, including changes in how buildings are designed, constructed and maintained.
“An exhaustive review of the scientific literature made it clear to us that it can be very hard to tease apart the health effects of exposure to mold from all the other factors that may be influencing health in the typical indoor environment,” said Clark.
“That said, we were able to find sufficient evidence that certain respiratory problems, including symptoms in asthmatics who are sensitive to mold, are associated with exposure to mold and damp conditions,” she concluded.
Excessive dampness influences whether mold, as well as bacteria, dust mites and other such agents, are present and thrive indoors, the committee noted. In addition, the wetness may cause chemicals and particles to be released from building materials.
A rare ailment known as hypersensitivity pneumonitis also was associated with indoor mold exposure in susceptible people.
Where evidence was lacking
But the committee said it was unable to find evidence that mold is associated with fatigue, neuropsychiatric disorders or other health problems that some people have attributed to fungal infestations of buildings.
The little evidence that is available does not support an association, the committee said, but it added that because there are so few studies it cannot rule out a connection.
Molds that are capable of producing toxins do grow indoors, and toxic and inflammatory effects also can be caused by bacteria that flourish in damp conditions, the report noted.
“Because there is a dearth of studies available on these topics, the committee wasn’t able to rule out a possible association,” Clark told a news conference.
Clark said the panel did not address the issue of whether ”toxic mold” exists but suggested such issues could be better communicated to the general public.
“There are certain molds that can produce toxic agents under certain conditions at a certain point of their life cycle that no doubt occurs at some point in buildings,” added panel member William Fisk of the Indoor Environment Department at the Lawrence Berkeley National Laboratory in California.
He said no one knows if these toxins can affect people.
Reports have focused on families who complained of serious problems that stopped days after they left a moldy house, only to return when they moved back in.
Clark said such reports are useless to a scientific panel. “One can’t use anecdotal data or individual cases to determine the extent to which a problem exists or doesn’t exist for a population of people,” she said.
The committee said information exists on how to control dampness but architects, engineers, building contractors, facility managers and maintenance staff do not always apply this knowledge.
The members called for development of guidelines for preventing indoor dampness and said they should be promoted nationally. In addition, building codes and regulations should be reviewed and modified as necessary to reduce moisture problems, the committee said.
Lawsuits claiming illnesses from mold in buildings that were not properly built or cleaned up have multiplied in recent years.
Changes in building codes in the 1970s to make homes more energy efficient and airtight had the effect of allowing less ventilation through a house that would dry out a wet wall or floor, which in turn may have led to more mold damage claims, according to attorneys involved in some cases.
The National Academy of Sciences is a private institution chartered by Congress to advise the government on scientific matters. The study was funded by the federal Centers for Disease Control and Prevention.
The full report is online at www.nas.edu.