Pneumono­ultra­microscopic­silica­volcano­coniosis¹ is a form of the illness pneumo­coni­osis, caused by the inhalation of a fine silica dust found in most volcanoes. It is also the longest word in the dictionaries of Random House, Merriam-Webster's and Oxford, beating 'super­cali­fragilistic­expiali­docious', 'flocci­nauci­nihili­pilific­ation' and 'anti­dis­establishment­arianism'. Some people believe the word is a hoax; others disagree.

The Word

• pneumono: Greek — 'lung', 'lung-related'
• ultra: Latin — 'beyond'
• micro: Greek — 'small'
• scopic: Greek — 'looking'
• silico: Latin — 'like sand'
• volcano: Latin — volcano
• konis: Greek — 'dust'
• osis: Greek — 'condition'

The word is pronounced as NOO-muh-noh-uhl-truh-mahy-kruh-skop-ik-SIL-i-koh-vol-kay-noh-koh-nee-OH-siss.

The Hoax

There is a theory that the word is a hoax created by the National Puzzlers League. At the 103rd meeting of the National Puzzlers League in the Hotel New Yorker in 1935, 'pneumono­ultra­microscopic­silico­volcano­koniosis' surpassed 'electro­photo­micro­graphic­ally' as the English language's longest word. The puzzlers claimed the word was an illness caused by ultra-microscopic silica dust, but there is no record of medical literature containing the word, hence the suspicion that no such word in fact exists.

The Disease

There are four types of pneumono­ultra­microscopic­silico­volcano­coniosis: chronic, asymptomatic, acute and accelerated. The chronic form is the most common and develops after being exposed to low levels of silica dust for 20 years or more.

When the dust is inhaled, it embeds itself in the alveolar sacs and ducts of the lungs, where oxygen and carbon dioxide are exchanged. When white blood cells respond to this infestation, they release a series of cytokines, which stimulate fibroblasts and result in fibrosis. The dust can also create silicon-based radicals, which release compounds that damage surrounding cells, such as hydrogen peroxide, hydroxyl and oxygen radicals.

The symptoms of silicosis are similar to those of the common cold, not including those which affect the nose and head. They can include faster breathing, severe coughing, a hoarse throat, loss of appetite, chest pain and increased susceptibility to tuberculosis.

There is no cure for the disease and there is no chance of recovering, but there are some things which can alleviate the symptoms:

• Making sure you are not exposed to other lung-damaging particles.
• Taking cough suppressants.
• Taking antibiotics and anti-tubercular agents to make sure tuberculosis does not develop.
• Doing physiotherapy for the chest.
• Lung transplantation.