Hydrogen is extremely flammable and explosive. Hydrogen is lighter than air so will dilute and disappear fast, meaning it is very difficult to detect, especially in outdoor areas.Hydrogen can be detected at two stages: Gaseous condition & Flammable condition Normally it will be necessary to detect escaping hydrogen in gaseous condition before it ignites and becomes flammable. Dräger delivers detection technology for both early hydrogen detection in the gaseous stage and in the flammable condition.