I have gotten a bad fill before.
Got down to 110' and the air tasted funny. I thumbed the dive, surfaced, got back on the boat and didn't continue.
I usually fill my own tanks, but this one had been commercially filled for me at a kinda-local shop since I had been diving there and had taken my own tanks with me. I dove my self-filled bottles for the other two dives of the day, and they didn't taste funny.
Dumped that tank (and another I had filled at the same shop at the same time) when I got home, and both still tasted funny even just sniffing what was coming out of the valve. Eeeeekkkkk. Did a quick vis check of the the tanks.... it has a nice little bit of flash rust in there that wasn't present when I bought the tank (I looked inside originally when I bought it) but no other obvious contamination. The other one was an Aluminum (and thus didn't have any rust in it) and it appeared clean. Both valves got torn down and inspected under a UV light. This shop claimed to have HFed, oxygen-compatable gas (I PP blend into my tanks, so this is quite important to me!)
I called the shop and told them about it; I hope they checked into it, because this kind of thing can be very un-funny. I don't know what was in that gas - but if I can taste it, I'm not breathing it. (The shop in question was rather cavalier about the report, but you never know how seriously they really are going to take something like this once they're off the phone.) The fills in question came off a bank of Nitrox - one hopes that if they found a bad cascade they would dump it, but you never know....
(This was NOT one of the local shops I've mentioned in the past.....)
If you detect a "taste" in your gas when diving, ABORT THE DIVE!
Taste in the gas can come from a number of sources. Some of them are of no great consequence. But most of them are - compressor oil (ALL oils are EXTREMELY toxic if inhaled, and can cause a form of pneumonia that is impossible to treat - this can KILL you), combustion byproducts (in the compressor due to carbon or other contaminents); you don't smell the CO but you DO smell the other byproducts - the CO can kill you outright, and ingested (at the compressor inlet) combustion byproducts such as vehicle exhaust.
If you've ever serviced a compressor filter stack with a "see-through" filter such as the Lawrence Factor cartridges you can SEE the contaminents that the cartridge filters out, as they are concentrated in the cartridge and very visible. Oil-lubricated compressors INTENTIONALLY pass a small amount of oil vapor through them to lubricate the upper cylinder walls, and that must be filtered out or it ends up in your tank! Some of what you see in those filters is just condensed water, of course. But the oil is also quite visible in a spent cartridge. You definitely DO NOT want that going into your lungs.
The problem with detecting an odor in the gas is that the filter cartridge(s) on a compressor are supposed to filter that out. That's part of what the activated carbon in the stack is for.
If THAT is not being effectively filtered out, what ELSE is also not being filtered out? The "what else" can easily be something like carbon monoxide!
I personally use a two-stage filter system - the primary on my compressor and then a secondary HyperFilter. So far, whenever I've changed the HF cartridge it has been completely (to visible inspection) dry and clean throughout. That would seem to indicate that the primary filter is doing its job - but I prefer a "belt and suspenders" approach to these kinds of things, as it only takes one tank full of bad gas to kill you.
Got down to 110' and the air tasted funny. I thumbed the dive, surfaced, got back on the boat and didn't continue.
I usually fill my own tanks, but this one had been commercially filled for me at a kinda-local shop since I had been diving there and had taken my own tanks with me. I dove my self-filled bottles for the other two dives of the day, and they didn't taste funny.
Dumped that tank (and another I had filled at the same shop at the same time) when I got home, and both still tasted funny even just sniffing what was coming out of the valve. Eeeeekkkkk. Did a quick vis check of the the tanks.... it has a nice little bit of flash rust in there that wasn't present when I bought the tank (I looked inside originally when I bought it) but no other obvious contamination. The other one was an Aluminum (and thus didn't have any rust in it) and it appeared clean. Both valves got torn down and inspected under a UV light. This shop claimed to have HFed, oxygen-compatable gas (I PP blend into my tanks, so this is quite important to me!)
I called the shop and told them about it; I hope they checked into it, because this kind of thing can be very un-funny. I don't know what was in that gas - but if I can taste it, I'm not breathing it. (The shop in question was rather cavalier about the report, but you never know how seriously they really are going to take something like this once they're off the phone.) The fills in question came off a bank of Nitrox - one hopes that if they found a bad cascade they would dump it, but you never know....
(This was NOT one of the local shops I've mentioned in the past.....)
If you detect a "taste" in your gas when diving, ABORT THE DIVE!
Taste in the gas can come from a number of sources. Some of them are of no great consequence. But most of them are - compressor oil (ALL oils are EXTREMELY toxic if inhaled, and can cause a form of pneumonia that is impossible to treat - this can KILL you), combustion byproducts (in the compressor due to carbon or other contaminents); you don't smell the CO but you DO smell the other byproducts - the CO can kill you outright, and ingested (at the compressor inlet) combustion byproducts such as vehicle exhaust.
If you've ever serviced a compressor filter stack with a "see-through" filter such as the Lawrence Factor cartridges you can SEE the contaminents that the cartridge filters out, as they are concentrated in the cartridge and very visible. Oil-lubricated compressors INTENTIONALLY pass a small amount of oil vapor through them to lubricate the upper cylinder walls, and that must be filtered out or it ends up in your tank! Some of what you see in those filters is just condensed water, of course. But the oil is also quite visible in a spent cartridge. You definitely DO NOT want that going into your lungs.
The problem with detecting an odor in the gas is that the filter cartridge(s) on a compressor are supposed to filter that out. That's part of what the activated carbon in the stack is for.
If THAT is not being effectively filtered out, what ELSE is also not being filtered out? The "what else" can easily be something like carbon monoxide!
I personally use a two-stage filter system - the primary on my compressor and then a secondary HyperFilter. So far, whenever I've changed the HF cartridge it has been completely (to visible inspection) dry and clean throughout. That would seem to indicate that the primary filter is doing its job - but I prefer a "belt and suspenders" approach to these kinds of things, as it only takes one tank full of bad gas to kill you.
