An odd question that I probably should know the answer to but.......
On a course last week we were looking at sewer and combined space rescues. For the practical exercises were were lowered 10m underground, carried out search and rescue then retrieved the casualty to the surface.
Although we usually work fairly shallow our kit allows us to drop a maximum of 50m with a working duration (9l cylinder) of 47 minutes. However we are looking at extending this with a surface supply.
Is there a risk of DCI working below ground but out of water? I seem to remember that there were a number of deaths when the London sewers were built that they put down to the bends? Is there a profile that can be followed as per our scuba ones to help reduce any risks?
I asked the question on the course but was told that the risk didn't exist, however this doesn't seem to fit with what I can remember.