Potassium nitrate is also called saltpeter and nitrite. It is commonly used to make gun powder and minor explosives, for curing meats and used medically for wounds (when combined with other chemicals). A single dose of more than 35 grams is fatal. Currently, potassium nitrate is created in a laboratory with very few natural sources utilized.
In Sheltered Areas
Potassium nitrate is a chemical compound that is made by the natural process of decay when various chemicals are introduced during this process. It is found as a white crystalline on rocks or cave walls where there was an abundance of decaying organic matter. Caves and sheltered areas were ideal locations for saltpeter to form, because they offered protection from the elements and they provided the required organic matter in the form of animal feces and urine. There have been large deposits found in ancient lake beds and deserts as well.
Because potassium nitrate can be found in soils, either by the natural decaying process or by the use of fertilizers, it gets absorbed into vegetables such as spinach, celery and cabbage. According to the University of Minnesota, the largest quantities of nitrates found in humans come from vegetables high in nitrates rather than from the consumption of meats that have been cured with potassium nitrate, such as hams and sausages.
You may know that potassium nitrate is used for curing meats, and for matches and fireworks. But, it is also currently used by manufacturers of toothpaste for sensitive teeth, even though there has been no scientific research that confirms its effectiveness in reducing sensitivity. You will also find this nitrate in drinking water in varying concentrations. That is due to runoff from the surrounding soils. There is ongoing research into what level of potassium nitrate is safe. Because of this uncertainty, manufacturers of baby food stopped using vegetables that contained potassium nitrate back in the 1970s.