[KarlInOhio]

flour and hydrogen peroxide?????

Pure hydrogen peroxide (not the 3% stuff in the drug store) is nasty stuff that decays to water and pure oxygen. Mix pure oxygen with something flammable and powdered like flour and your get a big boom.

[BenLurkin]

Got it.

Not the stuff from the store.

[HarmlessLovableFuzzball]

I would guess a liquid oxidizer like H₂O₂ would work best with a liquid fuel like kerosene, diesel, etc. Flour, of all the things ? I guess the Jihadists have studied the Anarchists Cookbook more thoroughly than anyone else.