A chemical burn occurs when living tissue is exposed to a corrosive substance (such as a strong acid, base or oxidizer) or a cytotoxic agent (such as mustard gas, lewisite or arsine).

The main types of irritant and/or corrosive products are: acids, bases, oxidizers / reducing agents, solvents, and alkylants.

Symptoms include itching, bleaching or darkening of skin, burning sensations, trouble breathing, coughing blood and/or tissue necrosis.

Substances that diffuse efficiently in human tissue, e.g., hydrofluoric acid, sulfur mustard, and dimethyl sulfate, may not react immediately, but instead produce the burns and inflammation hours after the contact.

Hydrofluoric acid leaches into the bloodstream, reacts with calcium and magnesium, and the resulting salts can cause cardiac arrest after eating through skin.