Hydrogen sulfide, or H2S, is well known to all employees of treatment facilities and oil and gas enterprises. This colorless gas not only smells bad like rotten eggs, it is also poisonous and explosive. Even its small concentrations irritate the mucous membrane of the throat and eyes, cause a headache, and sometimes the vestibular apparatus is upset. Exceeding the concentration of values of 1000/1000 000 lead to loss of consciousness and even death. It is no coincidence that where H2S is produced, workers are supplied with special instruments that detect this gas. The Swiss watch manufacturer North Eagles decided to equip its products with such a sensor. Detecting a given concentration of hydrogen sulfide, the watch blinks, vibrates, and gives alarm signals with a power of up to 96 decibels. The device can be tied to a smartphone. Then a notification about the coordinates of the gas leak will be sent to the emergency team from it.