Gunpowder and Gunpowder Tea
There is gunpowder (a chemical explosive [link] made from sulphur, charcoal, and saltpeter) and there is gunpowder tea (a type of tea rolled into pellets [link] that supposedly resemble gunpowder).
It is doubtful that any commercial gunpowder is rated as safe for food use in the United States.
There is one product made in New Zealand, Smoke & Oakum's Gunpowder Rum [link], that claims to use black gunpowder in its formulation.