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Chapter 24 — 4
TREATMENT
If a diver is affected by breathing contaminated air he should be separated from the source,
managed according to the
basic life support
principles outlined in Chapter 42, and gas from
his scuba cylinder should be sent for analysis to a chemical or gas testing laboratory, as
should that from others who used the same air compressors.
PREVENTION
The diver should breathe from his equipment before entering the water and should not use air
which has an unusual taste or smell.
As the expertise of compressed air (and other breathing gases) suppliers vary, divers are well
advised to obtain air fills only from a reputable supplier. Regular checks by local authorities
on the quality of the air are advisable, and in many places are now mandatory. It can be tested
by chemical detector tubes that determine the level of each specific contaminant. Drager (a
gas and medical equipment company) supply these tubes in a Drager Gas Detection Kit.
Many others are available.
Following any diving accident, suspect air can be tested by commercial gas suppliers and
State Health authorities.
Case History 24.2
A diving club had for many years been filling their cylinders from an air bank made up of large cylinders, the
source of which had been lost in the mists of time. It was decided to return the bank of cylinders to a major
industrial gas supplier for testing. The cylinders had their original paint in good condition – black cylinders with
a white collar. The gas company tested the cylinders, found them to be sound and refilled them according to the
colour code on the cylinders. Unfortunately, this was the standard colour code for pure oxygen and that is what
the company filled them with, having no idea that they would be ultimately used to fill scuba tanks.
A member of the dive club took delivery of the cylinders and reinstalled them in the bank. He did not know the
significance of the colour coding and assumed that because he was using the cylinders to store air that the
company would refill them accordingly. Because they were already full there was no need to fill them from the
compressor and the bank was immediately used to fill several sets for a dive the following day. Two divers
used tanks from this source on a dive to 20 metres. One abruptly convulsed 10 minutes into the dive and was
fortunately rescued by his buddy before he too convulsed.
Some clever detective work performed by the rescuing diver, and the diving physician they consulted,
established the cause of the problem as oxygen toxicity. Swift action by the police to round up all the
contaminated scuba tanks before they could be used, averted a major disaster. In this case, breathing from the
cylinder at the surface before the dive would not have disclosed any detectable difference from air.