How Dirty Is Your Humidifier?

Could steam from a humidifier also be spreading germs that can make you sick?
3:40 | 03/14/16

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Transcript for How Dirty Is Your Humidifier?
We're back now with "Good morning America" investigates. Today we're taking a look at humidifiers and what happens if you don't clean yours according to manufacturer's instructions. Gio Benitez is here. Reporter: We're calling this the great humidifier test. We did our own testing of ten humidifiers. Looking to see what we could find. The results, even surprised our experts. So, this morning, "Gma investigates." The steam from a humidifier, seen as a way to prevent sore throats and dry sinuses. Could that steam really be spreading germs that could make you sick? Most people don't know how to clean them. I don't know how to clean a humidifier. I know I'm not reaching all of the tiny corners. Reporter: Or don't clean them as often as they should. Gma investigating collecting ten humidifiers to test for bacteria and mold. Almost all admit they don't clean their humidifiers regularly. Some have asthma and allergies. We dropped the ten humidifiers from six different manufactures at lab at Thomas Jefferson university medical hospital. Out of the ten humidifiers, all had bacteria in the tank. Two had heavy bacteria, growing inside and also in the vapor that experts say could make our families sick. I was surprised by the heavy growth. Reporter: And in three of the humidifiers, mold. How are you? G gio. Are you ready to see what was growing in there? Oh, gross. Reporter: They found some bacteria. More importantly, they found mold in the vapor. Which means the mold is flowing out. That's not good, especially since we have asthma in our house and allergies. Reporter: Mold in this family's humidifier as well. This is what was growing inside. Mold can cause nasal congestion, sore throat. It can cause chest tightness or wheezing. Reporter: Now for the humidifier with the most bacteria and here are the results right here. Our experts labeling it extremely dirty. And experts say, what's inside could cause pneumonia. This is what was growing inside your humidifier. E O my gosh. Reporter: Because you're a nurse, you know what that means. Yes, it means my kids aren't safe. Reporter: Bottom line is, experts say you need to clean a humidifier every day. And every week, you should clean it thoroughly, according to the manufacturer's instructions. Those pictures. We reached to all of the humidifier man there fa-- man fpack Cher in the report. Lot of work, though. Some say claim to be self-cleaning. . That's right. Consumer reports is looking at that right now. They're sending that letter to the EPA. Coming up, that mayhem over March madness and the big twist

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