As a horse owner for over 30 years, I believe any horse undergoing ongoing medical treatment should have their shoes pulled. Absolute tragedy.

Oxygen does not burn; it merely supports combustion. I would focus on what flammable materials were allowed in the hyperbaric chamber.

They shouldn't have been horsing around.

What a tragedy....

Wow. I didn't even know they had chambers for animals. OSHA will likely require rubber hoof covers after this. Could these chambers be fitted with high volume tanks of regular compressed air that could be used to quickly push the pure oxygen out to reduce the flames should something happen? It might not save the animal from the fire but it might reduce the chance of an explosion.

What about a sprinkler or extinguisher system?

Reminds me of the time i was checking the gas level on the snowblower one dark winter night. I told my brother i could not see how much gas was in the tank and the dumb shiit handed me a bic lighter.

I'm still not clear on the explosion part of this story. Even in a pure oxygen environment, there has to be fuel to burn. Without that fuel being in the form of a vapor, objects will burn and burn rapidly, but not create an explosion. Being in a confined container, if the burning goes on long enough, I suppose it would create pressure to the extent of finally causing the container to rupture suddenly, which I guess you would describe as an explosion, but the sparks had to be in direct contact with a flamable fuel which in this case, that source is not too clear. The oxygen supply source can't explode...

Why wouldn't there be fire suppression systems and even pressure blow off devices installed?

Like others, I would expect metal shoes to be not allowed to begin with. They make rubber "boots" that can be placed over the shoes, but again the attachments of those is not guaranteed, so I would just make it a rule that they are not allowed in the chamber to begin with. It really isn't that hard to remove horse shoes... I have horses and I don't shoe any of them. I understand the need for them in some environments, but a horse undergoing rehabilitation or recovering from a medical procedure doesn't need shoes, IMO.

Very stange story and hard to understand quite frankly...

I imagine a horse fart in an oxygen chamber could be just about as much as a set up for an explosion as anything.

Man, the girl who was running the chamber wasn't the brightest of bulbs, eh? I mean, there's a huge tank full of pressurized pure oxygen right next to you ON FIRE, and you stand there staring at the screen and crying? RUN! RUN!

I wonder like others what the source of the "explosion" was. My guess is that because the chamber was sealed, when the contents began to burn, the chamber ruptured. And no, a horse fart would not be enough to cause an explosion. It would burn, but not once it was quickly diluted, even in pure oxygen.

Once again, science education fails us: How many people still think Oxygen can burn? I mean burn in the traditional sense. Oh, and how long do you think the tape was going to last on steel shoes?

Holy crap! too sad for any more of a comment than that.

Yepper, very tragic, indeed.

What was she distracted with, the visitor?

And not taping or bagging the metal shoes of a high volume methane generator and putting it in an oxygen rich atmosphere?

She wasn't thinking clearly, then as she found out the hard way... Methane + Oxygen + one spark = kablooey!

Too sad!

I wish the headlines to every update on this story did not state The Horse Caused The Explosion.

These women appear to have had no idea how dangerous this was. They did not think the material on the inside coud be exposed - which is why they started skipping the plasic covers over the shoes. Not only could it be exposed, it was from simple kicks - common with athletic young horses.

Also - the was faulty pressure valves that those discussing this believe may have caused the horse to react violently after 3 sessions of not reacting.

They should have both been trained to know a single spark means to evacuate.

The horse did not cause this. Human error did and by that, I do not mean the women so much as what they believed they were trained to do was correct.

I hope CNN follows up with OSHA and that all involved pay dearly - and that the woman who survived is well compensated.

I'm sorry anytime someone looses their Life needlessly. But we have to draw the line somewhere when it comes to our obsession with animals.

We are the only creature on this planet that confines animals against their own free will for our amusement. I am not talking about food and I am not talking about endangered species for which most are endangered due to our existence and thus we owe them something.

I am talking about just how much money the World over is spent not only to breed or capture our pets, (yes, I plead guilty to have owned some pets over the years when I had the resources, housing and physical ability to properly care for them). But to care for them long after they would have past on in the Wild.

We have destroyed many breeds of animals with our obsession for cross-breeding. We put billions into food and medicine to care for them. I am putting this out there, not to slam anybody. Just that we all need to think about our priorities on this planet.

I could make my share of smart ass comments or plead for the Humane treatment of animals. Rather that, I'd just like us all to start treating each other with the same love, respect and care as we treat our pets.

The educator’s dilemma: (Good Bad or Just the Most Basic, Oxygen’s Role)

Brooklyn Bridge Caisson Fire: (The notion that fires occur without mentioning oxygen or that compression of Air (20% Oxygen, 80% Nitrogen) by factor of 5 five does not increase combustibility, and the oxygen is somehow secondary to the fire, just indicates how poor the result of education are. Instead of just saying that Oxygen is the more significant than the spark that sets the fire then consumes material and therefore Oxygen can be dangerous, we go a about saying that oxygen is good, vital and health developing a common notion that in turn misleads us in long term complacency, leading to surprise and tragedy. We spend lots of resources saying how dangerous this or that other thing, doing anything to educate other than by rote.)

NASA School Demonstrations: Before the Apollo Fire, NASA sent representative to High Schools to perform demonstrations with Liquid Oxygen, among those demonstrations, were how rapidly a cigarette would burn after being immersed in liquid oxygen – poof gone -, and making a hammer from liquid mercury and then using it to drive a nail into board.

Cutting Torch/Lance: The welders cutting torch using H2C2 (acetylene) is ignited by a sparking device, the gas initially produces yellow flame and trail of soot. When the low volume oxygen is turned on to produce an intense flame. The flame is placed in near contact with iron/steel, heating the iron/steel to incandescence, once heated to melting the iron/steel catches on fire. At this point the welder can turn off the H2C2 gas boost the oxygen and the cutting process continues with pure oxygen by burning the iron/steel. Note that the iron/steel is NOT cut by melting steel, but by the burning steel to ferric oxide (FE2O3). The thickness of the steel that can be cut this way is astonishing, spanning many inches!

The internal combustion engine: Operates by compressing air (and fuel) by ratio 5 - 9 to 1, increasing the partial pressure of oxygen from 3 to 15-27 psi (20% concentration oxygen in Air (0.20*15psi) = 3psi, Nitrogen’s 80% (.80*15psi) = 12psi. This is roughly equivalent to having pure oxygen in the cylinder (and fuel). This could ignite by itself, but normal ignition is controlled by a spark plug, (hot spot in diesel). There are hundreds of millions vehicles doing the every day.

Atmospheric Science: The steady concentration of Oxygen in the atmosphere is a good starting point. We should know that oxygen is produced by plants, more so in summer, and constantly in the tropics and broadly in the Oceans. We should know that animals breathe oxygen, and that internal combustion engine consumes oxygen, fireplaces, forest fires, and industrial processes in vast quantities. It seems enough to balance the concentration, but could we be missing something, since it seems a very precise and steady concentration. As it turns out plant materials namely cellulose, when plant die and decay back into the soil the cellulose become peat, the same kind as we put in garden soil, but you may not know that peat vanishes into thin air, well not really but dry peat oxidizes in air having an Oxygen concentration of about 20%. A simple experiment can demonstrate the process, place a small quantity of dry peat moss in a mason or tomato sauce jar and place it in sunny window for few months, and take a look. It could be possible to measure the dry peat before and after, but this is beyond the precision of home implements. The simple point is that oxygen production and consumption varies too much to explain the constant value for oxygen concentration. Now you may also have heard that oxygen concentrations millions of years ago were higher, but it also reported that cellulose is a newer product that as not so wide spread as it is now?

Oxygen Blindness: We can appreciate the advances in the care of premature infants, but it was tragedy discovered when infants were placed given oxygen, it stimulated growth in blood vessels in the eyes and prevented the eyes from developing properly, and the result was impaired vision or blindness.

If I hadn’t seen it twice I wouldn’t have believed it: Having spent too much time gardening, tilling the soil, and tromping the occasional worm, that later dried in the hot sun, I was surprised twice by seeing the desiccated dead work vanish like a burning cigarette, and short lived flames. And I still do not believe it.

Oxygen doesn’t burn … therefore it is safe? No it is not safe, and it takes human intervention to keep it safe. But since it occurs so rarely the public masses are expected to remain ignorant.

Plausible Speculation: The horse came from a barn, trailer, pasture, on as sunny day (?). Horses are lovely animals, feeding on hay and grain, and after chewing toughly leave road apples. Over time these filaments of cellulose, dry and drift about. The horse is likely to be covered with dust and have those cellulose particles stuck everywhere. Next we challenge safety, by placing the animal dust and all into hyper-baric oxygen chamber. The news article did not mention if 100% oxygen was used, or what the pressure was applied. But it seems quite possible that the combustible materials were introduced into the chamber, and began to burn of their own accord. Yes the horse would be frighten and would kick wildly, sparks or no sparks, steel or no steel.

Conclusion: The horse began kicking after smelling smoke or feeling fire, the attendant cried because she knew what was happening. The horse caught in fire as was trapped, the heat and expanding gas and burning horse flesh over pressurized the chamber and the whole mess exploded. One person died, an animal died.

Suggestion or Solution: The obviousness of this incident (hindsight), is not the least bit that obvious, but knowing, accepting or proving what I have said here would be harder to prove than the solution. The animal being placed in such a chamber could be misted, wetted or lathered in moisture, to make sure that combustible matter cellulose cannot burst into flames. [Noting: Hospital Operating Rooms have caught fire for reasons of complacency.]

Wikipedia Apollo Fire:

Apollo 1 (also designated Apollo Saturn-204 and AS-204) was scheduled to be the first manned mission of the Apollo manned lunar landing program, with a target launch date of February 21, 1967. A cabin fire during a launch pad test on January 27 at Launch Pad 34 at Cape Canaveral killed all three crew members – Command Pilot Virgil "Gus" Grissom, Senior Pilot Edward H. White and Pilot Roger B. Chaffee – and destroyed the Command Module.[1] The mission name Apollo 1, chosen by the crew, was officially retired by NASA in commemoration of them on April 24, 1967.[1]

...

Wikipedia Other oxygen fires: (Note the Dates)

Several fires in high-oxygen environments had been known to occur prior to the Apollo fire. For example, in 1962, USAF Colonel B. Dean Smith was conducting a test of the Gemini space suit with a colleague in a pure oxygen chamber at Brooks Air Force Base in San Antonio, Texas, when a fire broke out, destroying the chamber. Smith and his partner narrowly escaped.[30]

Other oxygen fire occurrences are documented in certain US reports archived in the National Air and Space Museum,[31] such as:

Selection of Space Cabin Atmospheres. Part II: Fire and Blast Hazaards [sic] in Space Cabins. (Emanuel M. Roth; Dept of Aeronautics Medicine and Bioastronautics, Lovelace Foundation for Medical Education and Research. c.1964-1966.)

"Fire Prevention in Manned Spacecraft and Test Chamber Oxygen Atmospheres." (MSC. NASA General Working Paper 10 063. October 10, 1966)

On January 28, 1986, the Soviet Union disclosed that cosmonaut Valentin Bondarenko died after a fire in a high-oxygen isolation chamber on March 23, 1961, less than three weeks before the first Vostok manned space flight.[32][33][34] This revelation caused some speculation whether the Apollo 1 disaster might have been averted had NASA been aware of the incident.[35]