Otto fuel II

[2][3] Otto fuel II is a distinct-smelling (described by submariners as being similar in smell to wintergreen oil; i.e. sweet, fruity and minty),[citation needed] reddish-orange, oily liquid that is a mixture of three synthetic substances: propylene glycol dinitrate (the major component), 2-nitrodiphenylamine, and dibutyl sebacate.

Needing no oxidants and being a stable substance makes Otto fuel II ideal for use in the constrained environment of a submarine.

Finally, the fuel's energy density far surpasses the capacity of the electric battery used in other torpedoes, maximizing range.

Otto fuel II is a toxic substance found in EPA National Priorities List.

Ingestion of contaminated food or direct exposure at worksites can cause headaches, poor eye–hand coordination, eye irritation, congested noses, nausea, dizziness, and difficulty breathing.