Why Urine Was Once Used To Make Gunpowder

In a modern context, human waste is justifiably viewed as something that needs to be as out of sight (and smell) as possible. This has more or less been the case for thousands of years, with varying methods of disposal ranging from designated locations to complex sewage systems. The idea of waste matter being improperly disposed of is usually characterized as an infrastructural failing. However, urine has seen a surprising amount of application in daily life — from antiquity to the recent past — with accompanying infrastructure dedicated to its proliferation. 

Romans used urine as a bleaching agent for clothes and teeth and a medicine for treating both humans and livestock (via Mental Floss). In fact, its use was so common that Emperor Nero implemented a urine tax on buyers of the waste matter (via Smithsonian Magazine). Even when Rome fell, its use in mouthwash didn't disappear until the 1700s (via Spear Education). As disgusting as this comes across to modern ears, its utilization in this context was at least passive and not intended to harm. However, A.D. 850 set the stage for urine to become a crucial military resource, as this was the year gunpowder was born in China.

For centuries, urine provided the nitrate needed to make gunpowder

According to Britannica, early gunpowder generally consisted of 75% potassium nitrate, 15% charcoal, and 10% sulfur. While the latter two ingredients were fairly easy to acquire in the medieval world, potassium had to be sourced through a mixture of ash, animal feces, and urine. As alcohol was found to safely bind these components by the 14th and 15th centuries, the urine of drinkers became highly sought after (via The Drinking Business). By the 1800s, human urine in gunpowder had mostly been replaced by that of animals, but during the Civil War, material shortages led to the brief revival of human urine collection. 

John Haralson was the owner of a saltpeter factory in Selma, Alabama. By 1863, the livestock he used was no longer producing the amount of urine he needed, so he set out across his community to inform the local populace that they would do well to save theirs (via Timeline). Despite the ridicule, this practice allowed Haralson to produce ammunition for the remainder of the war. After this period, one of the more disgusting but lesser-known practices of the Confederacy (and humanity in general) began to finally come to a close.