If you think mold is just a harmless patch of fuzz in the corner of your shower, think again. Mold is far more common and worrisome than many people realize. According to the U.S. Federal Emergency Management Agency, mold colonies can begin forming indoors in as little as 24 hours after exposure to moisture, and they can grow in countless unsuspecting places. In fact, research found that nearly half the homes affected by Hurricane Katrina had dangerous levels of mold in the weeks and months following the storm.
And mold can be just as dangerous as it is common. The World Health Organization has confirmed links between indoor mold and upper respiratory symptoms, even in otherwise healthy individuals. Symptoms of mold exposure “include low-grade fever, pain in your muscles, shortness of breath and cough,” says Dr. Ana Zamora Martinez, a pulmonologist and medical director of the Interstitial Lung Disease Clinic at Mayo Clinic.
For especially sensitive individuals, mold exposure can also lead to chronic sinusitis, skin rashes and even life-threatening conditions like pneumonitis and invasive lung infections. Making matters worse, “for a majority of [mold] patients, there are no significant symptoms,” says Martinez. In other words, mold can cause damage without the affected person even realizing there’s a problem. When left untreated, mold exposure can even be deadly.
Here’s what causes mold to grow, what to watch for and how to deal with it if you discover it in your home.
What is mold? What does mold look like?
Mold is a type of fungus that thrives in moist environments, both indoors and outdoors. To the naked eye, it often appears as fuzzy, slimy or powdery patches that come in a variety of colors – most commonly green, white, black or even pink. “But it can also appear as subtle discoloration or brown, black, or yellowish staining at the edges of flooring or along baseboards,” says Devin Smith, a mold remediation specialist and co-owner of Sawtooth Water Restoration. “It often looks like water damage at first glance.”
Outdoors, mold plays a helpful role by decomposing dead organic matter. But indoors, it can wreak havoc. In addition to attacking the respiratory system, “some people can become allergic to the proteins produced by mold, and allergic reactions can trigger nasal allergies and asthma attacks for those who are sensitized,” says Dr. Rauno Joks, an allergist and immunologist at NYC Health + Hospitals in Brooklyn, New York.
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What causes mold?
“Mold requires moisture and time to flourish,” explains Kendall Noble, owner of the disaster restoration company True Restore. Indeed, mold can begin growing anywhere humidity levels rise above 60% or where there’s persistent moisture from leaks, flooding or trapped condensation. But moisture alone isn’t enough; mold also needs “organic nutrients to digest and grow,” says Noble.
This is why it rarely forms on non-porous surfaces like glass or metal. Instead, it’s typically “found in humid areas, growing on walls and natural, non-synthetic surfaces,” says Joks. Think building materials like “wood, drywall, carpet and paper,” says Rico Leon, a contractor, disaster restoration specialist and host of “Rico to the Rescue” on HGTV. “It’s especially common in kitchens and bathrooms where water is frequently used, but mold is also often found in basements, attics, laundry rooms, crawl spaces and many other places.” Even air conditioners have been recalled due to becoming sources of mold infestations. “Two of the most common places we find mold is behind or beneath the fridge and dishwasher due to poorly-fitted water lines,” says Smith.
And while most people recognize leaky roofs, burst pipes, poor ventilation and flooded basements as triggering mold in such places, there are also less obvious culprits. According to Leon, things like damp HVAC coils, dripping dehumidifier pans, trapped moisture under carpeting and poorly-sealed fixtures “can also fuel hidden growth in many overlooked areas of the home.”
Having inspected hundreds of mold-infested homes in his career, Noble agrees. “If you can see mold on a surface, chances are there’s a lot more of it lurking where you can’t see it,” he says. “What looks like a small patch could be the tip of a much larger fungal invasion.”
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How to get rid of mold
Once mold is discovered – especially if it’s already causing symptoms – “you need to make sure you and your family are steering clear of it or symptoms could worsen,” cautions Martinez.
DIY cleanup may be OK if you’re confident the mold is limited to a small, contained area and you have access to industrial-grade solvents and other specialized cleaning products. That means mold-specific cleaning agents, not bleach. “Many people assume bleach will get rid of mold, but it’s only effective on certain surfaces and won’t remove mold from porous materials,” says Leon.
Even with the right products though, “wearing personal protective equipment (PPE) is vital,” says Noble. This includes an N95 respirator, gloves and goggles.
Larger infestations require professional remediation. This is because specialists “can test the toxicity of the mold to know if there’s an emergency at hand,” says Smith; plus use containment barriers, HEPA-filtered negative air machines and advanced protective gear to prevent mold spores from spreading – especially through ductwork and HVAC systems. “Too many people clean up the mold they can see on the surface and then try to dry everything out with a fan, not realizing the fan is blowing harmful spores into other areas of the home,” says Noble.
Another benefit of hiring a professional is that they can help you find and fix the root cause of the mold-causing moisture. “Until you know where the source of your moisture is coming from,” says Leon, “your mold problem is only going to grow.”
This article originally appeared on USA TODAY: What is mold? And what causes it? Experts discuss.