h₂
Hydrogen

Although non-toxic, hydrogen can still accumulate in indoor and confined spaces which can result in the displacement of oxygen. Within spaces such as battery storage rooms, for example, a build-up of hydrogen can cause confusion, dizziness, nausea, and irritation to the respiratory system. In severe cases, it causes asphyxiation and even death.  

As a fuel, hydrogen is also highly flammable and so, in the case of leaks, there is a serious risk of fire and explosion. Hydrogen disperses upwards and, if ignited, will burn more easily than petrol or diesel. Fires can begin from just a spark of static electricity from a person’s finger, and as hydrogen flames are invisible to the naked eye and don’t produce easily detectable heat until in dangerously close proximity, identifying such fires can be difficult.  

As a compressed substance, hydrogen is stored and moved in liquified hydrogen tanks, making it very cold. Therefore, tank leaks can result in severe frostbite, or even the loss of extremities.