Electric Ray Attack & Oxygen Toxicity Inquiry

[Air_Diver_M.E.]

Good day.

I am working as an air (HSE-part-1) commercial diver and recently, I had a near miss while working underwater and would like to be advised and to inquire regarding the incident.

Forty five meters (45m) below after working for 20 minutes, suddenly I felt an electric shock in my body, felt it for three times. First and the second time I felt the shock, right away I called for help from the radio connected above. The third time, I lost consciousness and was pulled back and brought inside the recompression chamber. I got conscious again after half an hour inside the chamber itself. Underwater, when I was still conscious and asking for aid, my thought was: there must be an earth leakage on some of the electrical motors on the flat form. But then again, after the investigation it was confirmed that there was no leakage at all. The supervisor, client and other divers present in that time believed that the cause of the electric shock I got was only from an attack of an electric ray (i.e. torpedo ray) thru a volt discharge.

BUT – I am not convinced with the explanation given to me because when I was still conscious underwater, I am 3m off from seabed and did not see any fish around or near me. I believed that an electric ray (of any species) is always buried under the mud/sand and rarely they swam near the seabed only. I have been into this field for 15 years now and have encountered electric rays a couple of times while diving this depth or more – but have not gone unconscious because of being contacted with it, and as per my knowledge these species never attack and could not attack thrice continuously as they need to energized or recharge their selves even before they can produce another volt and I felt the electricity passing from my head inside my body and not coming from outside.

Therefore, I doubt that there must be a mistake thru negligence that the person in-charged that time opened the NitrOx valve 50/50 at the same time with the main air, on that depth of 45m instead of changing the breathing medium at 90 ft. for deco to NitrOx 50/50 alone to the surface.

NOW – kindly advice me for clarification of any fact and figures that divers (around the world, if any) got attacked by electric ray of any different species and had the same incident as mine. I got unconscious underwater due to that electric shock feeling I received for three times (continuously). I just got out from the hospital yesterday afternoon since the accident and had been in the ICU for 5 days. Complications in my heart (i.e. irregular / abnormal heartbeat / chest pain / problems in breathing) occurred after that incident. As of now I am under recuperation for a for another week and have been searching for some facts. I would like to know the exact reason / explanation enable to convince me, also to share my experience to other commercial divers in my field.

Please send me any information regarding O2 toxicity on this depth I had been during the incident (i.e. 45m), including the symptoms and warnings of the same. I would very much appreciate if anybody in this site could kindly provide some knowledge regardig the same.

Thank you very much, in advance.



Best regards

 

[erparamedic]

Wow... sorry to hear about your incident. I'm glad that you're recovering well. Unfortunately, I don't know anything about electric rays, so I'm no help there. Take care of yourself and hope your up to par soon.

 

[Doc]

What was your exposure suit protection around the area you got zapped?

What was the geographical location that this occured?

Can you rephrase this:

Therefore, I doubt that there must be a mistake thru negligence (?) that the person in-charged that time opened the NitrOx valve 50/50 at the same time with the main air, on that depth of 45m instead of changing the breathing medium at 90 ft. for deco to NitrOx 50/50 alone to the surface.

 

[pescador775]

It was not a torpile. You are correct about their recharge rate. They are not as powerful as Amazon eels and the ray would swim away, then bury in the sand to recharge. The convulsions you experienced were due to something else, something of unknown origin.

 

[drbill]

I don't know about electric rays in the Middle East (assuming that's where you were diving). Twenty years ago while filming a Cousteau documentary in the Channel Islands we had a diver zapped by our local Pacific electric ray. As I remember it, he did not lose consciousness but was kept out of the water for two days.

I'm only minimally literate on oxygen toxicity, but if you were breathing a mix of air and 50/50 at that depth you were certainly well over the 1.6 level (perhaps in the 2.8 range?). What was the duration of your exposure at that depth... how long did it take for them to bring you up to a safer depth? Remember, I am just marginally familiar with oxygen toxicity on anything but air since that's all I dive and only to depths of 180 ft.

 

[BarryNL]

I'm only minimally literate on oxygen toxicity, but if you were breathing a mix of air and 50/50 at that depth you were certainly well over the 1.6 level (perhaps in the 2.8 range?). What was the duration of your exposure at that depth... how long did it take for them to bring you up to a safer depth? Remember, I am just marginally familiar with oxygen toxicity on anything but air since that's all I dive and only to depths of 180 ft.

50/50 at a depth of 45m is indeed a pp 2.75. An exposure of 20 mins at that pp is well into the danger zone. I don't think you'd be given that sort of exposure even in a deco chamber.

 

[Mr. Bubble]

I am no MD or instructor, but it sounds like you were a guini pig for somebody. At the depth you mentioned, with the nitrox mix being 50/50, you were most probably subjected to O2 Toxicity. A Nitrox mix of 40/60 has a MAX depth of 99 feet, or 33 meters. So, you had 10% more pure O2 in your system, and 50 feet(17 meters) deeper than what you should safely dive. Therefore, it is my conclusion that you suffered O2 Tox, and the electric shocks you felt were really you having violent convusions, as well as why you became uncontious. You are lucky to be alive!

 

[cerich]

from what i see he wasn't breathing 50/50, he was breathing whatever 50/50 and air mixed would be(I can't be bothered to do the math). It may be the gas and tox or it may be something else that was not diving related.

I thought air at 45m for a working diver was pretty much gone these days....

 

[dsteding]

50/50 mixed at a 1-1 ratio with air will give you a O2 fraction of about 35%, which will give you a PPO2 of about 1.9 at 45m, still enough to tox . . .

 

[espenskogen]

50/50 mixed at a 1-1 ratio with air will give you a O2 fraction of about 35%, which will give you a PPO2 of about 1.9 at 45m, still enough to tox . . .

Just to clarify - When you are referring to 50/50, are you talking about a 50% heliox mix, or are you referring to a 50% EAN mix?