How safe is a HHO unit?
A HHO unit is as safe as water as that is where the hydrogen and oxygen is stored. Once HHO gas is released it is immediately consumed by the engine. When the vehicles engine stops the unit stops producing hydrogen. Water is a lot safer than petrol, diesel, hydraulic fluid, brake fluid etc Also hho is lighter than air and will dissipate upwards if it leaks unlike petrol etc which tends to pool in the lowest places.