ABSTRACT
The use of oxygen decompression of compressed air workers is still regarded as too dangerous by many people involved with tunnelling, although it is acknowledged by some authors as a helpful method of decompression because of faster nitrogen elimination and a lower incidence of decompression sickness (DCS). In this paper we present our experience of this subject during the construction of the São Paulo Subway Tunnels, from October 14 to November 16, 1976, involving a total of 3,693 man decompressions from 1.5 bar using either air or oxygen, with no fires or explosions and no evidence of oxygen toxicity. A comparative study is made of the DCS incidence between the two groups. We discuss the method of decompression used (Behnke’s oxygen decompression tables), system implementation, personnel training, safety measures and final results. It is considered that oxygen decompression for compressed air workers is a comprehensive and safe method to be used in working pressures of up to 1.5 bar for working shifts of 6 hours or more, provided its introduction to a working site is preceded by intensive and careful preparation of the personnel and materials involved and followed by close control and monitoring of the procedure.
