Fisheries Queensland director killed by Carbon Monoxide

[DandyDon]

Original A&I thread was last year - see: Diver missing off Brisbane, Australia

The news story is quoting "2366 parts per million (ppm) of carbon monoxide," which could be a mistake. A level that high would injure a diver test breathing while still on the boat, I think. It goes on to say that some other tanks from that compressor were tested finding "Of the five tanks that were tested, three contained carbon monoxide levels slightly above the maximum standard while two tanks filled on August 3 recorded 128 and 213 ppm." Lucky those two tanks were dive. Not all tanks were tested, but I bet all were drained.

I test every tank before diving it now. I'd share my detector with others on the boats, but sadly so little interest - and I am not going to preach. Some of the divers erroneously think that if my tank is safe then all of the tanks from that compressor should be, but there is no fact in that assumption. The news article...

Deadly gases in Fisheries Queensland director's scuba tank, court told

Fisheries Queensland director Andrew Thwaites died from carbon dioxide and carbon monoxide toxicity after his scuba tank was filled with "grossly high" levels of the dangerous gases, an inquest has heard.

It has also been alleged in court other tanks filled from the same compressor at the Underwater Research Group of Queensland clubhouse were found to have been contaminated with higher than usual levels of the gases.

Mr Thwaites drowned during a dive at Henderson Rock off the east coast of Brisbane's Moreton Island on August 10, 2016.

The 44-year-old's body was found by police divers the next day in a rocky outcrop near the sea floor.

The Brisbane Coroners Court heard on Monday all of the equipment Mr Thwaites used was tested by investigators and found to be in "good working order".

He also had enough air in his tank to make a safe ascent.

But the court heard a test of the remaining air showed it contained 2366 parts per million (ppm) of carbon monoxide as well as unusually high levels of carbon dioxide.

A second test returned similar results.

Queensland recreational diving standards state compressed gas should not contain more than five ppm of carbon monoxide.

The court heard Mr Thwaites filled seven tanks at the URGQ clubhouse on July 13, 2016, and following his death, Workplace Health and Safety Queensland emailed the organisation asking anyone who filled their tanks at the clubhouse to bring them in for testing.

Thirteen tanks from six people were handed into WHSQ but the department withdrew from the investigation before they could all be tested because the incident was outside their jurisdiction.

Of the five tanks that were tested, three contained carbon monoxide levels slightly above the maximum standard while two tanks filled on August 3 recorded 128 and 213 ppm.

Diving equipment store Dive Dive Dive also tested tanks belonging to URGQ members and posted the elevated levels of carbon monoxide to Facebook to warn others.

The store's page shows some tanks returned levels between 69 and 185 ppm.

Senior Constable Alastair Fenton told the court police did not check if other members of URGQ had filled up their tanks at the compressor as it was outside the realm of the investigation.

The compressor Mr Thwaites used broke down on August 8, less than a month after he filled up there.

The inquest is set down for the remainder of the week.

 

[SeaHorse81]

I'm curious as to the mechanics of how tanks filled from the same compressor could end up with markedly different levels of contamination. Do you know how that works?

 

[KevinNM]

A couple of sources, not an exhaustive list, from http://www.med.navy.mil/sites/nmcphc/Documents/industrial-hygiene/COMPRESSED-BREATHING-AIR.pdf

"Possible sources of CO include:
a. Motor exhaust drawn into compressor air intake
b. Generated within compressors as combustion product of fuels, lubricants
and overheated oils
c.Generated within compressors from oxidation of overheated sorbent filters.
CO accumulated on a filter can be released when there is a drop in operating
pressure."

All three of these can vary from one tank to the next based on the wind direction, how hot the compressor gets and whether the filter stack stays pressurized between tanks.

 

[runsongas]

direct fill without intermediary high pressure bank and compressor overheating/hopcalite breakthrough as it is run longer. first couple tanks pass muster but then the later ones are not.

 

[okvij]

What analyzer are you using and where can it be purchased?

Original A&I thread was last year - see: Diver missing off Brisbane, Australia
I test every tank before diving it now. I'd share my detector with others on the boats, but sadly so little interest - and I am not going to preach.

 

[DandyDon]

What analyzer are you using and where can it be purchased?

I've tried a few over the years. The PocketCO greatly disappointed me. Some that I found very usable...

Analox made a great one. No longer available as the market balked at the price, but if you can buy a used one, they will still help with updating.

The CooTwo is outstanding. You can get it in a model that tests of CO and O2 at the same time.

The Sensorcon works great and is the most economical. You can make an adapter to fit a tank, but I just use one gallon Ziplock bags - a new one every day as they do wear out quickly. Carry it in the bag, crack the valve before placing the bag over, catch a bag full of air, and watch for change. The reason I say crack before placing is I once shot a bag & PocketCO overboard when I opened the valve.
​

I appreciate that these may be difficult to find and service where you are, but there are other good ones. Good luck on your search.

 

[Anthony A.]

Is an analyzer necessary only if diving nitrox/gas or should even air tanks be tested before each dive?

 

[Blasto]

CO and CO2 contamination are just as - or really even more - relevant to air diving.

 

[DandyDon]

CO and CO2 contamination are just as - or really even more - relevant to air diving.

Slightly more, yeah than say partial pressure blended nitrox. When you increase O2 from 21% to 36%, you decrease the nitrogen in the mix as well as decrease any CO - but that's not likely to make a lot of difference. If the supplied air is tainted, a slight reduction is only a slight improvement.

Many divers are satisfied that not many CO hits are reported, but that's false security. Either investigating agencies (if any) don't/can't test, or the facts are suppressed like an infamous Roatan incident of recent years. The resort settled with the Texas widow in an agreement that prevents her from disclosure..

Padi no longer requires that compressors send samples to labs for testing, not that those tests provided real security, and Padi didn't even enforce that rule when they had it. Of the samples tested by one lab, 97% passed. If I had a 3% chance of dying on any dive day, I'd pass.

 

[tridacna]

Don,

How many bad tanks have you discovered since you started testing? I'm (fortunately) batting zero outta about 900.