Recently we heard yet another blending horror story. A rebreather diver dropped his oxygen cylinder off to be refilled on site, picked it up and decided to check the contents... to discover that it had been filled with 50% oxygen and not 100%. A potentially fatal mistake. He did the right thing, he analysed his gas...but too often divers abdicate responsibility and just assume that the blender knows what they are doing. They trust their lives to someone else...which is something I have an issue with.
So, what are the roles and responsibilities between diver and blender ? The rules and regs are simple enough. The diver is responsible for analysing his gas when he receives it. The blender is responsible for ensuring the person filling has completed an official blending course (including the exam) and that the diver signs for his gas.
The problem is that we all get to blase about it...and stop following the process. It is a pain for the blender to complete a log, the divers complain about the delay... and invariably blending is delegated to a low ranking employee who may or may not have the proper, official qualifications. All round it is a disaster waiting to happen.
Diver do not make it easier either. We had the instance the other day with a new client arriving to have Trimix fills. It was a bit of a last minute thing (as it somehow always tends to be). When Gerhard examined the tanks he discovered they did not have any markings indicating that they were oxygen cleaned. G phoned the client asking what the status was. The client was a little annoyed... what was the problem ? G explained that we do not fill cylinders without oxygen cleaning and if we do not know the tank, we will oxygen clean them ourselves to make sure. His reply, what is the problem ? It is only a small amount of oxygen you are adding. I started to have a small fit. Why ?
Well last year we had a small oxygen explosion, from a cylinder that we knew and trusted. Gerhard walked away slightly deaf and with a nasty burn on his arm. Did I mention that this was a cylinder with all its paper work and a diligent, trusted owner ?
The long and short of it was that the client was told that if he wanted us to fill his cylinder he would have to get them oxygen cleaned, either by us or someone who was qualified. For some reason he battled to grasp the concept that his R40 nitrox fill (ok, there were some more expensive trimix fills as well) was not worth Gerhard's life. And that is really what it boils down to.
As divers we do not want to be bothered with rules and processes. So here are a couple of things you can do to make the system work
1) Have your paperwork. Cylinders that are nitrox filled or trimix filled need to be oxygen cleaned by a reputable vendor
2) If your cylinders are filled at the coast they require an oxygen clean before you fill them with nitrox or trimix again. In fact, if you are filling with any sport shop you should get them oxyen cleaned before using them for mixed gas again. Simply put, clean gas is not easy to find and it only takes a small amount of oil to kill the blender.
3) Give the blender time to fill your cylinders. It can take 2 hours to do a Trimix fill and the more rushed the blender is, the more chance for errors
4) INSIST on signing for your mixes when collecting them from the blender and ALWAYS ANALYSE even if it is pure oxygen. If the blender is reluctant for you to sign remember he is legally bound to perform this check and if he still has no mechanism in place... create your own paperwork. If something goes wrong on the dive the first thing that will be examined is the mix in your cylinders... and it starts to get ugly when fingers are pointed at the person who blended...you... the person who placed the cylinders. So why not avoid the whole ugliness/
5) Take your own life seriously. Is it worth R40 (a nitrox fill), R500 ( a trimix fill ) ????