Risk of Disease Associated With Humidifiers

Excerpted from Home Humidifiers: Reducing Your Exposure to Harmful Bacteria, by Matthew R. Freije

Humidifiers are used to relieve dryness in the nose, throat, lips, and skin, and to alleviate nuisances such as static electricity, peeling wallpaper, and cracks in paint and furniture.

However, studies by the US Environmental Protection Agency (EPA) and the US Consumer Product Safety Commission (CPSC) found that some types of humidifiers can disperse microbes from their water tanks into the air. The EPA has not concluded that home humidifiers pose a serious health risk; nevertheless, it suggests use and care precautions to reduce the risk of exposure to harmful microbes.

Portable humidifiers have been blamed for cases of Legionnaires’ disease, a deadly type of pneumonia, due to inhalation of water mist contaminated with Legionella bacteria (legionellae). Researchers have confirmed that humidifiers can disperse  legionellae-contaminated mist throughout a hospital patient room. In one study, legionellae dispersed by a humidifier caused Legionnaires’ disease in guinea pigs.

The risk of illness associated with the use of humidifiers is greatest for older adults, children, smokers, and individuals who are immunocompromised either due to illness (e.g., cancer, diabetes, AIDS) or medical treatment (e.g., chemotherapy). You can use the following recommendations to reduce your risk of contamination.

For recommendations on safe use of home humidifiers, refer to Home Humidifiers: Reducing Your Exposure to Harmful Bacteria.