Even if we're exploring something as pathetic as an old ROC bunker only _one_ of us (usually me) goes down first and is attached to the end of a rope. If I stop talking then the person topside can do what they like to try and get me out, but under no circumstances do they come down behind me. We've also usually got a third person sat in the van (so just off site) communicating with us via radio and with GPS coordinates and road directions written down ready to give to the emergency services should it all go entirely to hell...

Sorry for the ramble; It's a horrible tragedy, but as what I've stated above is the level I expect for an unplanned slightly drunken Sunday-afternoon explore, I _really_ expect people in a commercial setting to know better. Probably more to the point, whoever ordered them to go in there deserves to be strung over the coals....

tldr: it's _really_ easy to go from 1 person slightly injured to multiple people dead :(

As they say in the diving industry about water and confined spaces: a deceptively easy way to die.

(irrelevant, but for the record, cave diving scares the pants off've me =) )

[1] http://www.michigan.gov/documents/lara/lara_miosha_moh_bulle...

My friends dad used to be a safety inspector duwnt' pit in the 70's and he's been trying to convince me to get an old Davy Lamp and to just pay attention to what the flame is doing, but I've yet to find a nice one (or inherit his). I have been known to ignite my cigarette lighter on every other rung when going down a ladder but in hindsight, that has the potential to end extremely badly.

Here in Finland, during second World War when petrol/gasoline was in very short supply, even army vehicles would run on CO gas. Petrol was only used for starting the engine.

Starting a truck involved first chopping little pieces of wood to a reactor attached to the car or lorry, lighting them and creating a fire with suitable under-supply of oxygen so that the reactor emits CO. When the gas is at right concentration to burn, start then engine with petrol and then switch to CO gas.

This is El Kamina, a modern hack made by the current Prime Minister in the country:

http://jalopnik.com/el-camino-driving-jalopnik-endorsed-bada...

Regarding its emissions, don't ask. Also, don't bother about burnout contests, it is not very powerful. But it runs on renewables.

https://en.wikipedia.org/wiki/History_of_manufactured_gas

I might have to start taking a household CO detector with me (the cheap ones now even have a PPM reading [1]) though I'm still wary of it giving a false sense of security and me then missing something else just as hazardous. Once again, Davy Lamp might be the solution to this -apparently the flame goes out when there's 17% oxygen or less, which is still life supporting.

[1] http://www.amazon.co.uk/Mudder-Carbon-Monoxide-Alarm-Detecto...

I worked for a short time at an installation that refurbished small oil rigs. It's about the worst kind of modern work environment: lots of poisonous substances (eg. heavy oil/crude leftovers), welding in closed spaces, tight crawlspaces and the whole thing is a basically a set of Faraday cages, so both VHF and cell reception is pretty bad.

Basically when you opened up a tank, you'd first have someone lower down a high precession meter to sample it over 12 hours. If that looked good, you have at least two gas meters per team, and the team is in constant contact with someone outside (either by said crappy VHF, and/or supplemented with a rope - pull the rope every minute - sound the alarm if the signalling stops, and send in a rescue team. If you figure an excellent 5 minutes from alarm to the team is inside, that's 6 minutes without air).

Worst accident we had was due to faulty documentation: a rig had stopped over and done an undocumented paint job. A team was repainting that section, on the inside of an enclosed space (a shaft) while another team was doing hot work (welding and/or cutting) on the outside. The old paint on the inside had cadmium in it - the result was 5-7 people airlifted to the hospital with cyanide poisoning.

For the record I sit at a desk all day poking at computers -it's just occasionally I and some friends have the urge to go exploring WW2 structures or old railway tunnels. If I were doing anything commercially or even if I were doing it more often then proper air monitoring would be essential. At the moment we're more than happy to eyeball something (or stand at the entrance and check for a breeze) and just decide "nope -not worth the risk".

I'm also hyper aware that actually, we don't really know what the heck we're doing (even though I spend a lot of time reading up on how similar has gone wrong for other people); so discretion has to be the better part of valour. If anyone reading this happens to be based middle of the UK, has a better idea what they're doing than I do and wouldn't mind me tagging along to learn some new things, then please please please, PM me :)

A couple of gas meters (the reason to have two, in case it's no obvious, is to try and make sure at least one sounds an alarm in case of faulty equipment etc) - and an "active" monitor to someone outside (aka: a rope) is generally as good as you'll get. And a lot better than what most people do.

Don't become the next anecdote at a search and rescue seminar.

I feel I should point out that I do try to be mindful not to become a statistic or anecdote. Apart from the obvious reasons, in 2015 it's hard enough to get away with having unsupervised, unstructured and unlitigated fun. If I do myself in through stupidity whilst exploring, climbing or gliding etc, then apart from anything else it's going to make it that much more difficult for anyone who comes after me. Imposing more restrictions or difficulty on a hobby I love is the last thing I want to be remembered for.

H2S, CO and O2 seem like the obvious gases to be mindful of; is there anything else you'd suggest looking for in an air monitor pr being especially wary of? Massive thanks for your time and knowledge :)

I think the main thing is to realize that enclosed spaces can be really dangerous. Farmers die in grain/grass silos every year. And people die from CO poisoning from using coal as heat-sources indoors, or just from theoretically sound, but flawed fire based heating solutions (eg: paraffin/diesel/oil heaters).

$400 multi http://www.alibaba.com/product-detail/Portable-diffussion-ty...

Though I'm somewhat wary about buying potentially life critical systems from AliExpress -especially when I have no idea how I'd go about testing, never-mind certifying it :)

gas detectors usually use active element and expire

There are too many stories like this where a whole bunch of people die trying to rescue the first victim so it makes total sense but it is kind of weird working in an environment where you know your colleagues will not help you (at least at first) if something goes wrong.

Btw: H2S doesn't really dull your sense of smell because of prolonged exposure. It only becomes odorless at deadly concentrations. So it turns out you don't know if you cannot smell it because it isn't present or it is just about to kill you.

That is really strange. Because at non-deadly concentrations it seriously stinks. Do you know why it has this weird backwards smelliness property?

https://www.mela.fi/sites/default/files/lietelanta.pdf

"Description of event

A farm-owner suffocated inside a manure tank which was lacking oxygen and contained toxic gases. Also his brother, who went in to help, died.

A tank of liquid-form manure was almost empty. A pipe at the bottom of the tank was blocked. The farm owner decided to enter the tank and finalize emptying the tank. However, he lost consciousness and fell to the bottom.

His brother, who was close by, saw what happened and went in to save the unconscious man, but he was also overcome in a moment. Four hours later a family member discovered the victims. Fire service was called to help, and with pressure air breathing equipment, they retrieved both men. They were both found to be dead. Cause of death was a poisoning by methane and hydrogen sulfide."

(Taken from farm advisory leaflet on manure https://www.mela.fi/sites/default/files/lietelanta.pdf )

"The lagoons themselves are so viscous and venomous that if someone falls in it is foolish to try to save him. A few years ago, a truck driver in Oklahoma was transferring pig shit to a lagoon when he and his truck went over the side. It took almost three weeks to recover his body. In 1992, when a worker making repairs to a lagoon in Minnesota began to choke to death on the fumes, another worker dived in after him, and they died the same death. In another instance, a worker who was repairing a lagoon in Michigan was overcome by the fumes and fell in. His fifteen-year-old nephew dived in to save him but was overcome, the worker's cousin went in to save the teenager but was overcome, the worker's older brother dived in to save them but was overcome, and then the worker's father dived in. They all died in pig shit."

Tough way to go.

From this excellent, long-form piece on Rolling Stone: http://www.rollingstone.com/culture/news/boss-hog-the-dark-s...

But I believe to have read quite a while back that H2S is why poop stinks so bad for us. It can lead to anoxic events: https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extin...

So evolutionary speaking we might have adjusted our olfactory sense to stay clear of any H2S sources.

After that, was lessons about watching for risks of fire and knowing where to GTFO.

I don't remember any at-the-time recent issues with asphyxiation and there were well known cases of barn fires every 5-8 years (we were replacing one that burnt down the year before). Still, the bigger warning I remember was about safety near manure.

Needless to say, we were warned about the dangers of H2S, and told that if it ever escaped the fume hood we would know immediately by the smell and should evacuate the premises before we succumbed to olfactory fatigue and poisoned ourselves. Another fun gas used in the same course was HCN. All in all, A very solid lesson in not fooling around outside the fume hood, and from the anecdote above a possibly life saving lesson which can't be said for most university courses...

For those who do not know, H2S is also a key part of the vile smell in flatulence, so strictly speaking it's a rather common substance in nature albeit in "safe" concentrations.

Funny story and probably TMI.

I used to work in aviation maintenance on large military aircraft. We regularly had to enter into "confined spaces" (fuel tanks, wings, ect) and were required to take a hand-held "air sniffer" with us that would alarm if any of about 5 or so monitored gases got too high.

I would always fart into the thing to see what would happen and it would always read 0 on all monitored gases. However on one day, I had perhaps the worst smelling "flatulence" ever and while inside the center fuel tank of a P3, I let one rip right into the sniffer. H2S went from 0 to 1ppm, but strangely carbon monoxide (CO) went from 0 to 7ppm. I always expected the H2S, but I don't know what the heck CO was doing in my bowels..

I was motivated to google, and much like radioactivity or electric current its possible to measure "scary" things to low levels that don't usually matter, and according to a 1982 gastroenterology paper that I found, aerobic fecal fermentation will produce an irrelevent yet measurable extremely low CO output while the anerobic fecal bacteria find CO to be a yummy fuel and will rapidly consume it. Unfortunately they cannot consume CO fast enough to scavenge your blood clean if you're suffering from CO poisoning, which is too bad. Carbon monoxide being known as that thing that gives you massive gas would be far preferable to being known as that poison that kills people, but thats how it goes, can't win em all, so despite our helpful fecal bacteria CO does kill people. The paper theorized the anerobes protect the host by eating the extremely small level of CO that normal aerobic gut flora output.

From fooling around with chemical sensors in my youth, quite a few work by heating up an oxidation catalyst and measuring its temp very closely given the carefully measured outside air temp and electricity fed into them. So feed it a fuel like carbon monoxide and it gets microscopically, yet measurably, hotter. You can play molecular weight games to get a catalyst that preferentially responds to light stuff like methane or CO, or heavy stuff like vaporized wax. My semi-educated guess is the aviation CO sensor got fooled by methane in the guy's gas. Methane isn't a serious threat in an airplane fuel tank so its unlike bowel gas analysis was a high priority in the specs. This is in the class of proving things by ruling them out, and you can't rule out a heated oxidation catalyst sensor getting fooled by low molecular weight methane, its a believable scenario.

Not really on topic but human microbiota papers from before the late 90's/early 2000's aren't the best -- especially when dealing with metabolic processes and outputs. Available technologies and techniques at the time made studying many commensal anaerobes very difficult.

Classic :)

After digging through ebay and google images for awhile, I finally found one of the two different units that we used: http://www.equipcoservices.com/sales/rae/multirae_plus.html

That one actually has, at least what sounds like, a built in aquarium pump that actually draws air into the unit.

The other style we used seemed to be completely digital. It made no noise and the main unit was big and bulky. The sensor plugged into it with long wires and the sensor it self was just a big heavy plastic cube. On one side it had a screen and behind the screen was just what looked like metal. As if it could sense gases through metal or something, dunno.

And I don't know which model I was using at the time of my "experiment"

http://www.ewinsen.com/Admin/uploadfile/201209/2012916105693...

It ends up being the same argument on a high level that for both operational and practical reasons the sensors usually respond to anything that burns / reduces in the presence of oxygen regardless of specific chemistry and design.

Many people each year succumb to H2S poisoning. It's a pretty insidious poison.

https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extin...

I remember trying to smell the substance by wafting[0] (as previous teachers had instructed us) and thinking 'hm, I thought I smelled that a second ago, but now I can't'. My teacher's response was 'oh, you're just not smelling it hard enough. You really need to take a big sniff' and stuck his nose over the petri dish to demonstrate.

Fortunately I was skeptical enough of him by this point in the semester that I ignored him. Only later did I look it up and discover that H2S is not actually odorless - it smell like rotten eggs. But it also dulls your sense of smell at the same time[1].

This is only one of several times when he almost killed us with labs in that class (my favorite was when he came just a second away from lighting a classmate on fire with Thermite[2]).

I'm really glad I'm not in high school anymore.

[0] https://www.youtube.com/watch?v=EQis0nnap74

[1] https://en.wikipedia.org/wiki/Hydrogen_sulfide#Safety

[2] https://en.wikipedia.org/wiki/Thermite

I don't doubt that it deadens the sense of smell, I'm just saying it's nowhere near odorless on first contact.

Of course, I never made an amount large enough, nor did I stuck around long enough, for the sense impairment to occur.

http://www.cdc.gov/niosh/docs/86-110/

https://web.archive.org/web/20150825171826/http://pipeline.c...

(Webarchive since original seems down)

http://blogs.sciencemag.org/pipeline/archives/2010/02/23/thi...

Probably just as well, that blog usually costs me several hours of work.

I've seen this article before, but I will never get tired of reading it again.

The FOOF article pointed out one other nasty problem, namely, how easy it is to game search systems:

"But I do note that if you run the structure through SciFinder, it comes out with a most unexpected icon that indicates a commercial supplier. That would be the Hangzhou Sage Chemical Company. They offer it in 100g, 500g, and 1 kilo amounts, which is interesting, because I don’t think a kilo of dioxygen difluoride has ever existed. Someone should call them on this – ask for the free shipping, and if they object, tell them Amazon offers it on this item. Serves ’em right. Morons."

Given how often I come across spammy search results in Google, I guess I shouldn't be too surprised.

I do. If I ever hear a huge explosion followed by a smoke column north of the city center, I know what my first suspicion will be.

http://blogs.sciencemag.org/pipeline/archives/2010/02/23/thi...

Thanks for the link and thanks to others for updated links! I'm in process of spamming all kinds of people with them haha. Hmm: need to get a hold of some FOOF that will go poof next 4th of July. :)

Ended up reading a PDF version of the book, Ignition!, mentioned in that article.

I do wonder if dry wit comes with the profession, btw.

Now that one is probably deserving a Darwin Award...

Hint: these are people.

Not as much as you might think. Firefighters routinely fought fires without SCBA up until at least the 70's, and probably into the 80's in rural areas. And if they weren't using SCBA for structure fires, they probably weren't using them for rescue calls in most cases. It was a cultural thing... for a long time, firefighters just didn't understand/appreciate the importance of SCBA. In hindsight that seems hard to believe, but it's been a slow process to get to a place where every firefighter is rigorous about making sure they use SCBA at all required times. (To some extent, that could be said about other protective gear as well, including turnout gear and PASS alarms).

Also consider that many (probably most) fire departments don't receive a lot of specific training on confined space rescue. Of course, you might ask, "why not?" and the simple answer is "time". Especially with volunteer firefighters, you can only get folks out for so much training a week. And fire calls are many times more common than confined space calls, so most training time is spent on the routine firefighting stuff.

Similar thing with hazardous materials training... it's a relatively recent thing for the majority of fire departments to receive specific haz-mat training, and even then, unless the department runs a specialized haz-mat team, their personnel probably only train to the "awareness" level.

I don't mean to excuse the fire chief, as I don't know the details of that specific story. But for something like that to happen, especially that many years ago, isn't a complete surprise.

Source: I was a firefighter and certified firefighting instructor throughout most of the 90s / early 2000's. My dad was also a volunteer firefighter and I've had a lifelong interest in the fire service.

Fortunately in my line of work "messing up" means pushing a bad commit, not dying at the bottom of a well.

Simple mistake to make.

The fire chief would have known that H2S is hazardous, but his training unfortunately (and obviously) didn't communicate just how hazardous it is.

These two facts make things a little worse imo.