The very existence of flamethrowers proves that some time, somewhere, someone said to themselves, "You know, I want to set those people over there on fire, but I'm just not close enough to get the job done." - George Carlin

Common misconception is that when a flamethower is shot and punctured that it will explode. It doesn't explode, but it can cause a large fireball. Which often looks like an explosion....

Read this Discovery forum post on the Myth of exploding flamethowers.

http://community.discovery.com/eve/forums/a/tpc/f/9741919888/m/2291905779

The quoted person below can explain what I mean far better than I can.

Not to split hairs - oh heck, yes, let's do that.

The word explosion is what's wrong. Used here it's a pardonable exaggeration, but an inaccurate statement nonetheless.

I'm going to use a US WWII M2 series flamethrower for discussion purposes. In it's original form, it used hydrogen for its compressed gas element. Hydrogen can explode when exposed to air and flame. However, they quickly switched to nitrogen, which is generally inert. If a bullet hit the nitrogen tank, no explosion.

As for the fuel, it's a thickened gas, just like napalm. It doesn't explode in its liquid state, and it doesn't vaporize to any degree worth mentioing here, so no explosion there, either. It burns. Period.

The pressurized nitrogen tank provided the 'push' for the fuel to be projected. If the pressure valve was turned off, and the thickened fuel tank was hit by a bullet, no fire or explosion, for the same reason a gas tank doesn't burn when shot. It needs to be exposed to air before burning, and there is none inside the tank. With an unpressurized tank, you'll get a slow leak (it IS thickened fuel, remember) which may eventually find an ignition source. The result: a fire, not an explosion.

If a fuel tank is hit when the pressure valve is on, still no explosion for the very same reasons. However . . . the thickened fuel is under pressure and will spray all over and is VERY likely to find an ignition source very quickly in combat. You still don't get an explosion, but you do get a big, spectacularly horrible fireball.

For purposes of conveying the horror involved, it may be understandable to misuse the term explosion. But for the purpose here of understanding the mechanics, explosion is not the correct word.
-binthere from discovery forums.

These shown are no longer in use...

Why should they be, we now have the M202A1 Flash(Flame Assault Shoulder Weapon).