A number of fuels have been used in fuel air explosive weapons. Among these are ethylene oxide and propylene oxide. Because of the ease with which is cloud of ethylene oxide or propylene oxide can be detonated, these two materials are the most commonly used. However, 25 these fuels have certain drawbacks. One drawback, common to both ethylene oxide and propylene oxide, is toxicity. Both materials are highly toxic. A concentration of 50 parts per million of ethylene oxide 30 in the air may have harmful effects on one breathing the air for about 8 hours. Propylene oxide is less toxic than ethylene oxide but is still highly toxic. A concentration of 100 parts per million of propylene oxide breathed for about 8 hours may have undesirable effects. Naturally, when fuel air explosive devices are stored in a confined 35 area such as aboard a ship, exposure for 8 hours is not unusual. Another drawback common to ethylene oxide and propylene oxide is the fact that both have relatively low boiling 40 points, 10.4 deg. C. and 34.2 deg. C. respectively. This makes the two difficult to handle in loading operations. High vapor pressures also contribute to difficulty in handling. A drawback particularly associated with ethylene oxide 45 is its tendency to polymerize during storage. Left alone in a fuel air explosive weapon or other container, ethylene oxide tends to self polymerize. The polymerized material is unsuitable for use as a fuel for a fuel air explosive device. Unpolymerized ethylene oxide, on the 50 other hand is highly desirable as a fuel insofar as detonability is concerned. Clouds containing from as little as 3 up to as much as 100 percent by volume of ethylene oxide are detonable. The detonation limits of propylene oxide, on the other hand, range from about 3.1 to about 27.5 percent by volume. 55 SUMMARY OF THE INVENTION It has now been found that 1,2-butylene oxide, when used as a fuel for fuel air explosive devices, exhibits marked superiority over either ethylene oxide or propylene 60 oxide. The marked superiority stems from the fact that 1,2-butylene oxide is about 3 times safer than propylene oxide when long exposure to it is required and about 3.5 times safer than ethylene oxide. Insofar as ease of detonation is concerned, 1,2-butylene oxide has about 65 the same explosive limits as propylene oxide. However, 1,2-butylene oxide is significantly easier to handle because its boiling point is nearly twice that of propylene oxide--63 deg. C. as opposed to 34.2 deg. C.--and over 6 times that of ethylene oxide. According to this invention 1,2-butylene oxide may be used in either its natural 5 liquid state or gelled with a hereinafter named gelling agent.