This case of fatal poisoning by nitrogen tetroxid fumes is reported for its medicolegal interest and also because of the rarity of the condition and a general lack of recognition of the pathological changes in the lungs of persons dying from the action of this very dangerous gas.
When nitric acid acts on certain metals, such as copper, silver, or cadmium, a gas is given off with the composition of NO or nitrogen dioxid. When this gas comes in contact with the air it absorbs oxygen, with the production of nitrogen tetroxid or N2O4. If either of these compounds of nitrogen and oxygen comes in contact with moisture, nitrogen dioxid forms nitric acid, while nitrogen tetroxid is slowly decomposed into nitric and nitrous acids. These are the decompositions which occur when brown fumes are given off by the action of nitric acid on the substances mentioned
WOOD FC. POISONING BY NITRIC OXID FUMES. Arch Intern Med (Chic). 1912;X(5):478-504. doi:10.1001/archinte.1912.00060230075007