Formic Acid Facts, Dangers and Uses

Formic acid is an irritating chemical present in the sprayed venom of some ant species and in the secretion released from some stinging nettles. It's dangerous at high concentrations, but at low concentrations it's very useful. Humans use formic acid as a food preservative, since it's an antibacterial substance. It’s also used to kill pests, to produce food and cosmetic additives, and to help a variety of industrial processes to occur.

Our bodies make small quantities of formic acid from the methanol that we ingest, inhale, or produce. Some of the methanol produced in the body is made from the sweetener known as aspartame. The body converts aspartame into aspartic acid, phenylalanine, and methanol. The methanol is then converted into formic acid. Fortunately, researchers say that the formic acid in our body is generally too dilute to be dangerous.

 acid family. It's also known as methanoic acid. The chemical's molecular formula is HCOOH. The molecule is composed of a carboxyl group (COOH) with a hydrogen atom attached. In the carboxyl group, the carbon atom has a double bond joining it to the oxygen atom and a single bond joining it to the hydroxyl (OH) group, as shown in the illustration above.

Formic acid can be made synthetically in laboratories. In nature, it usually exists in the form of a colorless liquid. This liquid freezes at 8.3 degrees Celsius (46.9 degrees Fahrenheit) and boils at 100.7 degrees Celsius. (213.3 degrees Fahrenheit). It has a strong odor and is often described as having a "pungent" smell.

The dangers of formic acid depend on its concentration. At higher concentrations, formic acid is corrosive, has a strong smell, and produces dangerous fumes. It produces burns and blisters on the skin and injures the eyes and the mucous membranes in the mouth, throat, and respiratory system. Inhaling concentrated formic acid makes breathing difficult. Swallowing the concentrated acid causes severe ulcers (sores) to appear in the digestive tract as well as pain and nausea. Prolonged exposure to formic acid may produce liver or kidney damage.