Ozone is used across a surprisingly wide range of industries, from cleaning drinking water to fading denim jeans to disinfecting root canals. It’s one of the most powerful oxidizers available, meaning it breaks apart contaminants, bacteria, and odor-causing molecules on contact. That reactivity makes it useful in dozens of applications, but it also makes it dangerous to breathe, which is why most of its uses involve controlled environments.
Water Disinfection
The single largest use of ozone is treating drinking water. Ozone disinfects water roughly 3,000 times faster than chlorine and works by physically destroying bacterial cell walls rather than just neutralizing organisms chemically. It also handles pathogens that chlorine cannot, including Cryptosporidium, a waterborne parasite responsible for gastrointestinal outbreaks that resists standard chlorination.
The other major advantage over chlorine is what ozone leaves behind: nothing. Ozone reverts to ordinary oxygen within minutes, so it doesn’t produce the byproducts that chlorine does. Chlorine disinfection generates compounds called trihalomethanes, which are linked to cancer risk with long-term exposure. Ozone also performs consistently across different water pH levels, while chlorine becomes less effective in highly alkaline water. Many municipal systems in Europe and increasingly in North America use ozone as a primary disinfection step, sometimes followed by a small dose of chlorine to maintain residual protection through the distribution pipes.
Food Safety and Shelf Life
Food processors use ozone to kill bacteria on produce, meat, and juices without leaving chemical residues. In one study on fresh peach and grape juice, four minutes of ozone exposure eliminated more than 99.999% of Listeria monocytogenes, a dangerous foodborne pathogen. The treatment also preserved the juice’s color, nutritional content, and taste while extending its shelf life.
Ozone is applied as either a gas or dissolved in water, depending on the product. Leafy greens, berries, and other fragile produce are often treated with ozone-infused wash water during processing. Because ozone breaks down into oxygen so quickly, it doesn’t alter flavor or require rinsing, which gives it a practical edge over chemical sanitizers in fresh food applications.
Textile and Denim Bleaching
The clothing industry, particularly denim manufacturing, has adopted ozone as a cleaner alternative to conventional bleaching. Traditional cotton bleaching relies on large volumes of water and harsh chemicals like hydrogen peroxide, contributing to significant water pollution and chemical waste. Ozone bleaching achieves comparable whiteness with dramatically lower environmental impact.
A lifecycle analysis comparing ozone bleaching to conventional methods found that ozone reduced global warming potential by 27%, human toxicity by 84%, and freshwater ecotoxicity by 58%. The process works at just 30% fabric humidity with a 20-minute treatment time. For denim brands marketing sustainability, ozone fading has become a standard technique to create worn-in looks without the water-intensive stone washing or chemical treatments that the industry traditionally relied on.
Medical and Therapeutic Uses
Ozone therapy refers to the controlled use of an oxygen-ozone gas mixture for medical treatment, and it has been applied to a growing list of conditions. In a multicenter, randomized, double-blind clinical trial, intramuscular ozone injections were tested for acute back pain caused by lumbar disc herniation. Ozone has also shown efficacy in treating fibromyalgia, chronic fatigue syndrome, and multiple sclerosis symptoms, according to research published in The Lancet Regional Health.
During the COVID-19 pandemic, ozone autohemotherapy (where blood is drawn, exposed to ozone, and reinfused) was used as an adjunct treatment. A preliminary study of 100 patients with lingering post-COVID fatigue reported improvement in symptoms. The therapy remains more widely accepted in parts of Europe and Latin America than in the United States, where it is not FDA-approved for most conditions, though clinical research continues to expand.
Dentistry
Ozone gas is used during root canal procedures to disinfect areas that traditional cleaning instruments can’t fully reach. After infected tissue is removed from the canal, ozone is introduced into the space, where it penetrates microscopic crevices and kills bacteria, viruses, and fungi. The gas reaches areas that liquid disinfectants may miss because of its ability to diffuse into tiny tubules within the tooth structure. Some dentists also use ozone to treat early cavities, applying it to tooth surfaces to kill decay-causing bacteria before the damage requires drilling.
Smoke and Odor Removal
Professional restoration companies use high-output ozone generators to eliminate smoke odors after fires. The process works after the main cleanup is complete: once soot, damaged materials, and standing water have been removed, ozone generators are placed inside the sealed space. When the concentration builds high enough, the gas oxidizes the odor-causing molecules left behind by combustion, breaking them apart at a molecular level rather than masking them with fragrance.
For heavily damaged properties, professionals typically divide the building into sections and treat each one individually to achieve strong enough concentrations. The space must be completely evacuated during treatment. All people, pets, and plants are removed, and the area is aired out thoroughly before anyone re-enters. This same principle applies to eliminating mold odors after flooding, pet odors in rental properties, and cigarette smoke in vehicles.
Why Ozone Is Dangerous to Breathe
The same chemical reactivity that makes ozone useful for killing bacteria makes it harmful to lung tissue. Even relatively low concentrations cause chest pain, coughing, shortness of breath, and throat irritation. Ozone worsens asthma, reduces the body’s ability to fight respiratory infections, and affects healthy people as well as those with existing lung conditions. Exercising while exposed increases the risk because you inhale a greater volume of air.
Workplace safety limits set by OSHA cap exposure at 0.10 ppm averaged over eight hours. The FDA limits indoor medical devices to 0.05 ppm of ozone output. For context, an EPA study found that a single consumer ozone generator marketed for rooms up to 3,000 square feet produced concentrations of 0.50 to 0.80 ppm when placed in a 350-square-foot room, five to ten times higher than public health limits. Even with doors open to adjacent rooms, powerful units on high settings reached 0.12 to 0.20 ppm, still above safe thresholds.
This is why ozone generators sold as home “air purifiers” are a concern. While ozone does react with some airborne chemicals, the concentrations needed to meaningfully remove indoor pollutants far exceed what is safe to breathe. At concentrations that stay within health guidelines, ozone does not effectively remove most indoor contaminants. The EPA has been clear on this point: ozone generators are not recommended as air cleaners in occupied spaces.