Wikipedia.png
There is more information available on this subject at Triamino hydrazine on the English Wikipedia.
A model of a hydrazine

Triamino hydrazine is a fuel used by the UNSC. The root material, hydrazine, (N2H4), has been used as a rocket fuel since Earth's Second World War.

Triamino hydrazine is compressed and stored in fuel tanks of thruster packs. Though an efficent fuel, triamino hydrazine is extremely volatile. If a thruster pack's fuel tank is ruptured, it will cause a fatal loss of control for the wearer.[1]

Triamino hydrazine is also used as a fuel for propulsion pods on some civilian commercial freighters, such as Horn of Plenty.[2]