Can humidifier disinfectants cause lung disease?

What's actually in it

Some people add chemical disinfectants to their humidifiers to prevent mold and bacterial growth in the water tank. Products marketed as humidifier cleaners or sanitizers contain biocidal chemicals that get aerosolized along with the water mist. You breathe these chemicals deep into your lungs every time the humidifier runs. In South Korea, this practice led to a public health disaster when hundreds of people developed severe lung disease.

What the research says

A 2026 study in Ecotoxicol Environ Saf examined the link between humidifier disinfectant use and respiratory diseases, including how long it takes for symptoms to appear after exposure. The researchers followed people who had used these products and tracked their health over time.

Users of humidifier disinfectants had higher rates of asthma, bronchitis, and interstitial lung disease. The scary part was the latency: some people didn't develop symptoms until years after they stopped using the products. The chemicals had done their damage silently.

The disinfectants work by killing microbes, but they don't stop at germs. They also damage the cells lining your airways. Over time, this leads to scarring, reduced lung capacity, and chronic breathing problems.

The safest way to keep a humidifier clean is to empty it daily, scrub it with vinegar, and let it dry completely between uses. Adding chemical disinfectants to the water turns your humidifier into a chemical delivery system aimed straight at your lungs.