Washington Roebling's Caisson

Origin
Washington Roebling was an American civil engineer who worked on the Brooklyn Bridge and designed two caissons for the bridge’s construction. In 1870, a fire broke out in one of them, where Roebling tried to extinguish the flames. Working in the compressed air caused him to develop the bends, better known as decompression sickness. Roebling became unable to visit the site and had to see its completion off-site and later dealt with the after effects of the condition for the rest of his life.

Effects
It causes a form of decompression sickness that manifests within hours after entering the caisson. If not treated, the person will develop muscle and joint pain, headaches, fatigue, vertigo and itching. Worse symptoms include breathing difficulties, seizures, loss of consciousness and leg weakness.

It has been noted that stepping inside the caisson when pressurized can stop its original effects and for a short period help breathing.