Potassium nitrate, also called saltpeter, is water-soluble crystalline solid that is most commonly found in explosives and fertilizers. It can cause mild symptoms when people get exposed to it, including eye and throat irritation, so avoiding contact with the substance is recommended. However, there are some cases where you may need to use a product that contains potassium nitrate, so it is important to learn where it can be found and how to properly use products that contain it so you don’t compromise your health.
Natural Sources
According to the “Science Encyclopedia,” the natural source of potassium nitrate is in rocks. The chemical occurs naturally in the ground, forming a white crust on other rocks. It is commonly mined in ancient European seabeds, brine lakes and soil that is rich in organic matter.
Gunpowder
Potassium nitrate has been used in gunpowder for over 2,000 years, first by the Chinese and later moving to Europe and the rest of the world. It is used in a mixture of approximately 75 percent potassium nitrate, 15 percent carbon and 10 percent sulfur. Today, it is also used in other weapons, such as grenades and bombs, which contain gunpowder and similar explosives. It was also once used in dynamite and TNT, but today has been replaced by more efficient explosives.
Food
Potassium nitrate and other nitrates/nitrites can be used in food preservation in small doses. According to the University of Minnesota, a fatal dose of this substance for adults is 30 to 35 g. In smaller doses, potassium nitrate can cause methemoglobinemia, a condition in which the blood cannot easily carry oxygen throughout the body. Infants are extremely susceptible to this condition after ingesting small amounts of potassium nitrate. Some fruits and vegetables may also contain potassium nitrate and other nitrates/nitrites, since these chemicals are naturally found in organically rich soils.
Fertilizers
Because plants grow well in soil with potassium, many fertilizers contain potassium nitrate. It is most commonly used to grow fruits and vegetables rather than flowers, trees and other plants. It has a low salt index, which makes it better than sodium-based chemicals for some crops, such as celery, potatoes and tomatoes.
Other Sources
In addition to potassium nitrate that is found in explosives, food preservers and fertilizers, there are a few other places where the chemical could also be found. In the past, it was used with sodium carbonate in a medicine called sal prunella that was meant to relieve sore throats. It is also used today in fuses and matches.