Saltpeter, War, and Enslaved Labor
Near Mammoth Cave, Kentucky
During the War of Eighteen Twelve, the British navy blockaded American ports and choked off imported gunpowder. Suddenly the dirt inside Mammoth Cave became a strategic resource. That cave dirt was rich in calcium nitrate, left behind by organic matter such as bat droppings over thousands of years, and calcium nitrate is the heart of saltpeter, the main ingredient in black gunpowder.
The cave became a factory. Workers dug the earth, packed it into large wooden leaching vats, and poured water through to draw out the nitrate. The solution was pumped to the surface through hollowed-log pipe and boiled down into saltpeter for the eastern powder mills.
At its peak the works turned out saltpeter at an industrial scale. Nearly all of that brutal labor fell on enslaved African American men, around seventy of them, leased from surrounding areas and forced to work long hours in the cold, dark, dust-choked air. Remnants of the vats and pipes they built can still be seen in the cave today.
When the war ended, the market collapsed, and the cave turned toward a very different future.
