In particular, napalm made poorly or with incomplete mixing can end up being very similar to gasoline, with its attendant hazards. Gasoline, being a volatile, easily ignited compound with a high energy density, was immediately used as a weapon in war. In World War I, both Germany and the Allies used it in flame throwers, but it burned itself too quickly to be very effective at igniting the target of the flame throwers. As you might imagine, intensive research to slow down the burning was funded by the U.S. government, and in 1942 Harvard University scientists and the U.S. army chemical warfare service found a way to jelly gasoline that worked quite well. This mixture was a big hit with the allied forces, who used it extensively in World War II in flame throwers and fire bombs in the latter part of the war.
Popular weapons continue to be refined and developed, of course, and napalm was no exception.
With many more compounds available after World War II, a safer and just as effective napalm compound was developed. Instead, polystyrene and benzene are used as a solvent to solidify the gasoline. Hence soldiers smoking around napalm-B face no hazard at all. Yet a reliable igniter can be used to start napalm-B burning exactly when you want it to do so. The above information comes from the Encyclopedia Brittanica article on napalm, and from Scott E. Harrigan, who kindly provided me with information about the various types of napalm as described in Incendiary Weapons by Malvern Lumsden.