Editing Decompression sickness (section)

=== Leaving a high-pressure environment ===
[[File:Caisson Schematic.svg|thumb|300px|alt=Schematic of a caisson|The principal features of a caisson are the workspace, pressurised by an external air supply, and the access tube with an airlock]]

When workers leave a pressurized [[Caisson (engineering)|caisson]] or a [[mining|mine]] that has been pressurized to keep water out, they will experience a significant reduction in [[ambient pressure]].{{r|38uhms | Elliott}} A similar pressure reduction occurs when [[astronaut]]s exit a space vehicle to perform a space-walk or [[extra-vehicular activity]], where the pressure in their [[spacesuit]] is lower than the pressure in the vehicle.{{r|38uhms | Dehart | Pilmanis | Vann2}}

The original name for DCS was "caisson disease". This term was introduced in the 19th century, when caissons under pressure were used to keep water from flooding large engineering excavations below the [[water table]], such as bridge supports and tunnels. Workers spending time in high ambient pressure conditions are at risk when they return to the lower pressure outside the caisson if the pressure is not reduced slowly. DCS was a major factor during construction of [[Eads Bridge]], when 15 workers died from what was then a mysterious illness, and later during construction of the [[Brooklyn Bridge]], where it incapacitated the project leader [[Washington Roebling]].{{r|Eads}} On the other side of the Manhattan island during construction of the [[Downtown Hudson Tubes|Hudson River Tunnel]], contractor's agent [[Ernest William Moir]] noted in 1889 that workers were dying due to decompression sickness; Moir pioneered the use of an [[airlock]] chamber for treatment.{{r|Hudson}}