Home Dangers

Your Home; The Dangers Of Mold In Homes

By JAY ROMANO

Published: October 7, 2001

MOLD can cause health problems that range from itching eyes, sneezing and coughing to serious allergic reactions, asthma attacks and even permanent lung damage. And what many people do not know is that mold could be growing in their homes right now.

''I've gone into houses that are so neat and clean there's not even a teacup out of place,'' said Jeffrey C. May, principal of J. May Home Inspections, an indoor air quality testing company in Cambridge, Mass. ''Then I go into the basement and find mold growing on the legs of the furniture.''

Mr. May, the author of ''My House Is Killing Me: The Home Guide for Families with Allergies and Asthma'' (Johns Hopkins University Press, 2001), said that while mold in a house is most often found on walls, floors, ceilings, carpets and fabrics exposed to moisture, one particularly troublesome hiding place is inside the ductwork and associated components of central forced-air heating and air-conditioning systems.

''This is the time of year my phone starts to ring off the hook,'' Mr. May said, explaining that as homeowners start up their central heating systems many find themselves suddenly coughing, wheezing and sneezing.

Mr. May said that while mold needs moisture, oxygen, a food source and a surface on which to grow, a mold spore in search of a home can come by those essentials relatively easily, even inside a central heating system.

That is because such a system constantly circulates mold spores found naturally in the air through parts of the system that often have dust on their surfaces.

Once a mold spore has embedded itself in that dust -- which provides the nutrients it needs -- all the spore needs is moisture. And that moisture, Mr. May said, can come from condensation produced by the air-conditioning coil, from a faulty humidifier attached to the system, or even from high levels of humidity in the air itself.

While it is possible for mold to grow in the ductwork of a central heating system, he said, it is more common to find it in the parts of the system that collect the most dust and have the greatest potential for being exposed to moisture: the air-conditioning coil and its fiberglass lining, and the cabinet that houses the blower fan.

''I've seen coil linings that were completely infiltrated by mold,'' Mr. May said, adding that when the heating system is turned on, the blower fan distributes mold spores throughout the house. ''Most people don't even know they have a problem until they start getting sick.''

In most cases, he said, the only way to determine with certainty whether mold is growing inside a central heating system is to gain access to the coil, its lining and the blower, and take a dust sample from the surface of the components.

That sample must then be examined under a microscope. ''I'm looking to see whether there's actively growing mold in the dust,'' Mr. May said.

He explained that he looks for actively growing mold because it is possible for mold spores from other areas of the house to get caught in the dust in the furnace.

''I'm trying to distinguish between mold that is being collected in the system and mold that is growing in it,'' he said.

The cost of an inspection can range from $200 to $1,000 or more, depending on scope and complexity.

If active mold is found in the heating system, Mr. May said, a homeowner should hire a professional remediation expert -- preferably one certified by the National Air Duct Cleaners Association, a trade group based in Washington -- to clean the furnace and the ductwork. Its Web site is www.nadca.com.

''You want to make sure the whole system is cleaned thoroughly,'' he said, explaining that in addition to removing any dust and mold in the blower cabinet and air-conditioning coil housing, a remediation expert should also clean the interior surfaces of the ductwork with a brush and a HEPA vacuum.

If there does not appear to be actively growing mold in the heating system, but members of a household have reason to suspect there is mold elsewhere in the house -- either because inactive spores were found in the heating system or because they are experiencing respiratory problems -- additional testing may be necessary.