Google the phrase toxic mold and you'll come up with a staggering 375,000-plus hits. Many are for sites recounting tales of families fleeing, and even torching, homes infested with fungi so toxic that they have been linked to brain damage. You'll also find plenty of sites hawking do-it-yourself "mold test kits" and attorneys specializing in "mold litigation." Is this just hype, or does mold really pose a health threat?
It does, just not in the way you might think. The truth is, all molds, even nontoxic types such as Chaetomium and Mucor (the ones that colonize your shower), can make you sick. In fact, nontoxic molds are most likely to make you ill, because they're much more common, says mold expert Jay Portnoy, MD, an allergist at Children's Mercy Hospital in Kansas City, MO.
Mold comes in thousands of different strains, but only a few, including the notorious Stachybotrys chartarum, aka black mold, produce toxins. Researchers acknowledge that these toxins are potent enough to cause serious problems in healthy people. But they are still debating whether people are actually exposed to high enough concentrations to cause major illness. "There isn't yet sufficient evidence to prove or disprove this," says Stephen C. Redd, MD, chief of the air pollution branch at the Centers for Disease Control and Prevention.
However, there is already plenty of evidence that all molds can potentially cause rashes, headaches, dizziness, nausea, allergic reactions (like hay fever), and asthma attacks. In people with weakened immune systems, they can cause serious lung infections.
Don't Let Mold Move In
Like mushrooms, molds are members of the fungi kingdom. They and the tiny spores they generate to reproduce need only water and something living or once living—like old wood—to eat. They thrive outdoors, hitchhiking into your home in dust and dirt on your clothes and shoes, on air currents, and in water that enters through cracks in walls and foundations. Once inside, they proliferate anywhere moisture exists. Notice a musty odor? You have mold.
In hot, humid months, more mold spores than usual surf the breeze. Check Web sites and newspapers for the daily mold count. On days when the count is high, close your windows (to keep spores out) and run an air conditioner (which dehumidifies). No AC? It's not ideal, but open your windows to keep indoor humidity down and prevent spores already inside from multiplying. No matter what the weather, the real key to avoiding mold problems is to keep things dry. What you should do:
Vent. Turn on an exhaust fan or open a nearby window while showering, bathing, running the dishwasher, or cooking, since all these activities produce water vapor. Make sure clothes dryers and all gas appliances are vented to the outside.
Monitor moisture. Use a hygrometer (about $20 at hardware and home stores) to check the indoor humidity level. If it exceeds 55 percent—most likely in summer—lower it by running an air conditioner or dehumidifier. In cold weather, indoor humidity should stay around 30 percent.
Fix leaks and dry waterlogged areas. If the pipes burst, the roof springs a leak, or a new crack in the foundation ushers water in, fix the problem ASAP. If you find a leak, dry the area pronto. "Within 24 hours, most molds are growing," says Berlin Nelson, PhD, an expert on plant pathology at North Dakota State University. Rent a wet-vac to dry floors. Use a space heater and fans to dry wallboard and ceiling tiles. Get professional help if you can't quickly manage solo.
Declare War on Spores
Though molds are often a dark color (black or brown), they may be green, yellow, or even an incongruously delicate pink. They usually spread out in a circular pattern. Don't worry about finding out what type you're dealing with, says Redd. Just clean it up. If you have asthma or are allergic to mold, get someone else to do the cleanup.
Scrub the small stuff. You can easily and safely tackle swatches of about 1 square foot on tiles, walls, windowsills, and other hard surfaces even if toxic mold has gained a foothold there, says Portnoy. To be extrasafe, put on a pair of goggles, an N-95 respirator (about $5 from hardware and home stores), and rubber gloves. Then scrub with a brush and a dilute bleach solution such as Tilex.
Know When You Need a Pro
If mold covers more than a square foot, get professional help. Ditto if you can smell but can't see mold—that means it's probably behind a wall or wallpaper. Don't play Bob Vila: Knocking a hole in the wall or peeling back the wallpaper can release so many spores that you can become seriously ill whether you're allergic or not, warns Portnoy.
Replace porous moldy things. It's nearly impossible to remove mold from the tiny pores in wallpaper, ceiling tiles, carpeting, and dry-clean-only upholstery.
Vacuum. When it dies, mold sheds substances that can accumulate in house dust and continue to cause sneezing, coughing, itchy eyes, and asthma attacks. After cleaning up mold, go over all surfaces with a vacuum that won't disperse it into the air, such as a central vac or one equipped with a HEPA filter.
Find a Reputable Pro
Mold remediation "experts" don't have to be licensed or certified, so here's how to find a reputable one.
Look for an experienced company that is affiliated with the Institute of Inspection, Cleaning and Restoration Certification or the Association of Specialists in Cleaning and Restoration.
Check the firm's references and record with the Better Business Bureau.
To avoid being scammed, hire one company to inspect your home for mold problems and another to fix them.
Ask the firm you hire to follow professional guidelines, such as those in the Environmental Protection Agency's document Mold Remediation in Schools and Commercial Buildings, which apply to homes, too.