Ozone in a Hot tub: useful or just a marketing gimmick—and is it dangerous?
Ozone dissolved in the water of Hot tub Hot tub is generally harmless—it becomes a concern only when present as a gas in the air we breathe, where it can irritate the respiratory tract. Whether ozone in Hot tub Hot tub is dangerous depends primarily on ventilation and dosage. There is currently no mandatory occupational exposure limit in Germany, and chlorine or bromine do not fully replace ozone.
