CSB Safety Video: Dangers of Propylene Cylinders

September 13, 2019 posted by

Narrator: On a scorching day
in June, 2005, propylene gas, venting from a cylinder at a compressed gas
filling and distribution facility ignited, setting off fires and
explosions that lasted five hours. The accident occurred
at the Praxair Company, located near a historic residential
district in Saint Louis, Missouri. Exploding cylinders were
propelled into the neighborhood. Fortunately, no one was injured, although the flying
debris caused property damage to buildings and cars. Everyone at the facility
managed to evacuate safely. The U.S. Chemical Safety Board
investigated the accident and issued a Safety Bulletin on the dangers of
propylene cylinders exposed to high outside temperatures. Merritt: The fire at Praxair was serious and not the
only one that has occurred at compressed gas facilities. The accidents show the
need for companies to follow best safety practices for outdoor
cylinder storage and fire protection. These measures will help protect
firefighters and the neighboring communities. Hall: The Praxair fire revealed problems with
pressure relief valves widely used on propylene cylinders. The valves present a
potential danger during hot weather. Narrator: On June 24, 2005,
Saint Louis was experiencing a heat wave; the high temperature that day
was recorded at 97 degrees. At Praxair, thousands of compressed gas cylinders
containing highly flammable products, such as propylene, propane and acetylene
were stored outside in the direct sunlight. As the sunlight beat down on the cylinders,
heat also radiated from the asphalt, driving up the temperature and pressure
of the gases inside the cylinders. At about 3:20 p.m., increasing pressure inside
one cylinder activated its pressure relief valve. Gas pushed against the spring-loaded plug,
allowing propylene to flow around it. Gas moved past the spring, out of the
valve and through openings in the cylinder cap. The propylene vented to the outside air and formed a
flammable vapor cloud around the top of the cylinder. A static charge, created by the venting propylene,
most likely ignited the vapor. A Praxair security camera
recorded the vapor release and ignition. The vapor begins escaping from the cylinder,
seconds before 3:20 p.m. It ignites immediately. An employee sees the
fire and sounds the alarm. Within 30 seconds, the
fire is spreading rapidly, heating surrounding cylinders, causing them
to vent gas, adding more fuel to the flames. Just over one minute after
the initial vapor release, smoke begins to darken the facility as
the fire rapidly grows out of control. Ninety seconds into the incident, the camera
records blinding flashes as cylinders begin to explode. Cylinders begin rocketing through the air,
further spreading the fire. Narrator: Because the
alarm was sounded quickly, all workers and
customers evacuated safely. This news footage, recorded
by KMOVTV shows the fireballs from exploding cylinders of propylene,
propane and acetylene. [Sound of explosion] Narrator: Gas cylinders,
primarily of acetylene, rocketed up to 800 feet into the nearby community,
damaging property and starting fires. Large fragments were later found on sidewalks,
front and backyards and parking lots. One piece landed near a yard
where children were playing. Cars were set ablaze. One flying cylinder knocked this hole
through the wall of a residential townhouse. Fortunately, no bystanders
were injured by the flying debris. Although firefighters
set up remote water sprays, they had to remain at a distance
and could not enter the facility. [Sound of explosion] Narrator: An estimated 8,000 cylinders were
destroyed by the fire, which took five hours to control. The Saint Louis Medical Examiner
attributed the death of one resident to an asthma attack triggered by the
noxious smoke and fumes from the fire. Hall: This accident occurred because a propylene
cylinder vented highly flammable gas into the open, where it could easily ignite. Narrator: U.S. Department of Transportation regulations
require pressure relief valves on propylene cylinders. But the CSB found that the pressure relief
set points specified in industry standards are too low for propylene and allow the
gas to begin venting during hot weather, well below pressures that
could damage the cylinders. Not only are the specified set
points too low for propylene, the CSB found that some valves begin releasing
gas even before the pressure reaches the set point. Finally, we found that each time a pressure
relief valve opens, its performance deteriorates, making it more likely to vent gas
at too low a pressure in the future. Narrator: In addition to the
incident at Praxair, Saint Louis, the CSB investigation looked
at three similar incidents, including this one at the Airgas Distribution
facility in Tulsa, Oklahoma in August, 2003, a fire and explosions at the Air Liquide
plant in Phoenix, Arizona in June, 1997 and a fire at Praxair’s Fresno,
California facility in July, 2005, just one month after the accident at
the company’s Saint Louis facility. All involved the ignition of leaking propylene and all occurred on hot summer days
with temperatures above 100 degrees. This video, shot by the Tulsa Fire Department
as firefighters sought to contain the 2003 fire, shows the extensive offsite damage that occurs
from cylinders rocketing into nearby communities, setting fire to homes,
vehicles and businesses. Selk: Gas cylinder fires spread very quickly and exploding cylinders put
firefighters’ lives at risk and endanger the public. The CSB’s Safety Bulletin recommends a number of
best practices for cylinder storage and fire protection. Narrator: We urge companies to
install fixed fire protection systems, such as fire monitors
or water deluge systems, which can cool cylinders and prevent the fire from
spreading during the first critical moments after ignition. Gas release detectors can be used in storage areas
to sound alarms and trigger fire protection systems. Barriers such as concrete walls can be installed
to confine exploding cylinders to the storage area. Merritt: The key lesson from the CSB’s
investigation is that many relief valves still in use today on propylene cylinders could lead
to catastrophic fires during periods of hot weather. Narrator: The CSB recommends
that the Compressed Gas Association, the industry’s primary safety organization,
revise its standards for propylene relief valves. These valves need improved reliability
and also a greater safety margin between the pressure of propylene inside the
cylinders and the pressure at which the valves open, so that they do not vent prematurely. Some compressed gas distributors, including Praxair, are
already replacing relief valves on propylene cylinders. Merritt: Propylene cylinder fires
and explosions can be prevented. Thank you for watching
this CSB Safety Video. Narrator: For more information about the
Praxair accident and the CSB Safety Bulletin, please visit our
website at CSB.gov.


63 Replies to “CSB Safety Video: Dangers of Propylene Cylinders”

  1. MainsOnTheOhmsRange says:

    I hope they all change the valves in the future.

  2. BarneySaysHi says:

    Or in a airconditioned bunker.

  3. BIN Industrial Training says:

    A miricle no one was hurt.

  4. baileys60 says:

    90 seconds. fuck

  5. ComputerTechTV says:

    I remember watching this on the news live somewhat close by.

  6. Holy-Terrorist says:

    Holy-Terrorist:>*=* Omg, my comment are 3 year ago.
    *=* I haved 1 LSD experience in my 4 year old and after haved serious accident caused me a bad trip and finally repaired, i want dicover around me, of i hate parents of is impossible to funny, of making me a delirium with lose of memory. :/

  7. Holy-Terrorist says:

    Holy-Terrorist:>*=* Really, i not looked all the video, sorry.

  8. Holy-Terrorist says:

    Holy-Terrorist:>*=* I dont taked drug about long time in 4 year old into 20 year old today, a strange history.
    I haved chance to have very little memory from my past.
    I speak french and little english.

  9. fla playa says:

    H O L Y S H I T!!! That was horrific. Can hardly believe that only one person perished from an asthma attack… Amazing!

  10. fla playa says:

    375 psi for propane (the release valve setting). What do you guys bet they used the same ones for the much more volatile propene? We learn as we go I suppose. One person died and I'm grateful the death toll wasn't 10 or 50. I'd estimate an increase of 25-35% vapor pressure with the unsaturated propene. The release valve obviously did not accommodate that increase.. I'll just take a quick guess and call it 500 psi for propene.

  11. Why for Christ's sake did they store these eplosives in open air, on a space that looks like a parking lot!? What is worse, this storage facility is right in the middle of a residential area!!!! On every spray can there's a safety precaution, like: " Keep away from direct sunlight", but no need to worry, let's put thousands of Propylene, Acetylene, and other -lene gas cylinders under the blazing sun, and wait for things to happen! I wonder from what kind of zoo the supervisor of this Praxair plant was taken…Do you still tar and feather idiot plant managers in the US??? Dear Ms. Merritt, I have a safety recommendation for you that is fairly simple: in addtion to redesigned safety valves on Propylene cylinders and the installation of fire precaution / detection systems: just make the operators of such plants store their cylinders in a cool environment, to prevent them from heating up in the first place!

  12. Grant Chisholm says:

    They should store the cylinders in side the facility

  13. Grant Chisholm says:

    Under the feclity

  14. Grant Chisholm says:

    Cold air to

  15. Grant Chisholm says:


  16. Grant Chisholm says:

    I mean boom

  17. Samad Farooq says:

    Aslamo Alikum, peace and blessings of God be upon you. We are all brothers and sisters and children of one man Adam and one woman Eve. All people belong to God and God belongs to all of them. All people come from God and go back to God, so all are One. We are all in same boat and in same train which starts from God and ends at God. One of the God’s name is Ahsan-al-Khaliqeen which means whatever God created is extremely beautiful and excellent. So we are all beautiful and excellent. The beautiful girls and guys all around us in this world are nothing but our beloved sisters and brothers. Not only we humans are just one family but all the angels, all the devils, all the plants, all the animals, all the mountains, all the winds, all the oceans, all the insects, all the birds, earth, sun, moon, all the stars, all the planets, all the galaxies, all this universe and everything inside it is just one family created by God and there is nothing like God and none equals to God in anyway. He is All-Loving, All-Forgiving, All-Knowing, All-Merciful, All-Gracious, All-Wise and All-Powerful. So we have a very big family. May God forgive all of us and unite all of us in His love and mercy and in His obedience. If we will be thankful to God and obey Him, this world will become a paradise. And on Day of Judgment, God will give us even a bigger paradise so beautiful and lovely that we cannot imagine where all of us will live in joy and pleasure forever. Please never forget to say many thanks to God and praise Him all your days and nights and ask for His forgiveness all the time. God wants we love others like we love ourselves. Ameen. Jazak Allah. 🙂

  18. SHERMAN YOUNG says:

    thanks , I am a Welder and that information was very helpful for me.. well done

  19. TruckerPhilosophy says:

    I remember working on the clean up crew that August. It was the most brutal job I've ever had.

  20. Phillip Lopez says:

    TRUMP says OSHA we don't need no sticking OSHA !!!

  21. Nullveer says:

    I was there. Brian Williams was with me.

  22. Bad Duck says:

    Town house ?? Lol more like crack house

  23. donwa777 says:

    How about not storing gas cylinders on asphalt in direct sunlight?

  24. Seeking TKO says:

    They have a license and are legit to do business..

  25. MrPLC999 says:

    A very common industrial process is to stand around and thoughtfully ask the question…"What could go wrong?" As the scenarios come to mind, take each one and say…"Oh that'll never happen." Then go back to sleep and wait for it.

  26. Justin Koenig says:

    What have we learned today:
    1) Don't store compressed gas Cylinders in direct sunlight, on asphalt
    2) DO build at least a sunroof over the cylinders
    3) DO raise the cylinders off the ground, and preferably store on wood pallettes, which are both easily avaliable, and are poor absorbers of heat. (correct me if i'm wrong, sounded good to me)
    4) Have an automatic fire supression system on the premises, which activates WHEN A GAS LEAK! is detected. this will prematurely stop any chances of an explosion.
    5) Have some fucking common sense…
    and lastly:
    6) apply your fucking physics major or chemistry or what the fuck ever, and please calculate what the pressure needs to be to meet safety standards, which are well documented by local authorities.

  27. The Great Mechanized Ape says:

    they should be rupture discs only set to about 100 psi before the tank fail pressure. two per tank.

  28. ಠ Tocki Cohi ಠ says:

    CSB "urges companies to use fire protection systems" – How about 18 days in county jail for each of the CEOs & management teams responsible for these potential death trap facilities? And proportional fines and/or delisting them from stock exchange for a quarter? Considering Praxair has ANOTHER incident a month later at a different facility – some punitive measures seem more than called for? Maybe sounds harsh, but the mitigation efforts would be minimal to prevent this. Wooden pallets and shade mesh and a few staple guns fellas.

  29. Max Steiner says:

    Who needs terrorists when you have clowns like Praxair running facilities like this.

  30. gorillaau says:

    Crap! One heck of a fire. How do they determine that a destroyed gas bottle vented prematurely? I love forensics.

  31. William J. says:

    “OK. Here’s your assignment. I want you to fly a helicopter near some exploding, airborne gas cylinders.”

    Umm…. Yeah….. I think I’ll just quit.

  32. TeuFel Jones says:


  33. Crimson Halo says:

    Moral of the story: a $100 aluminized tarpaulin goes a long way in the summer sun.

  34. king james488 says:

    so the over-pressure release valve designed to keep people safe caused an accident… good job.

  35. Tom says:

    I sell propylene and propylene accessories.

  36. StCreed says:

    You can do a lot to prevent this, and then you can do a lot to prevent extra damage when something goes wrong. But you can also just pretend nothing will ever go wrong and save yourself a lot of money in the short run. Great for your quarterly figures, although I cannot for the live of me understand how an insurer would go along with this inept handling of flammable gasses.

  37. Aaron Bays says:

    Can't believe the gross negligence here. It wouldn't be that expensive to put up something like a pole barn or shed with an aluminum roof and open sides(so it can vent if one leaks) to keep the sun off those cylinders. Put them on wooden pallets to keep them off the hot asphalt, the air gap would make a huge difference in the temp on those tanks as well.

    Only people that won that day were the lawyers for all the various insurance companies involved. RIP to the poor person who died from the fumes, I can't imagine a more horrible death than being gassed.

  38. Gary Vale says:

    sounds like the tanks didn't like standing at attention in the hot sun all day and revolted ……tank lives matter …………..

  39. The Jason Knight Fiasco Band says:

    Hire real actors to portray CSB personnel. They all have of the personality of an EBT card. Or at least get them to memorize their lines. Listening to them read from dummy cards kills every episode for me.

  40. Allan Wright says:

    Is it possible to store gas cylinders like those in the video in an enclosed building

  41. Syclone0044 says:

    Wait, what?! At 2:17 the video states that the vented propylene gas was likely ignited by static electricity caused by the releasing gas?? First off, how is that possible? Second, so basically the safety relief valve is more of a guaranteed bomb detonator? Quite peculiar…

  42. honestmcgyver says:

    Having watched a few CSB videos all I hear is recommendations…no teeth…surely there should be an ability to change regulations?

  43. LastAvailableAlias says:

    These CSB videos are very well done

  44. Aleatha Vogel says:

    The narrator sounds like he's trying to do his best John de Lancie impersonation. 😉

  45. remote5555 says:

    Just like a stalin organ.

  46. The Dolphin says:

    Several posts quoted the existing regulations of "… do not store above 125F …" but these bottles vented at 98F air temp. Hmmm, so there's a problem for a start! Trouble is, if the ashphalt factor drove that higher, how does a company know actual BOTTLE temp on a hot day? Even 125F (51C) can be exceeded on a very hot day. Try Australia where some towns get to 45C (113C) in the shade!
    In the end, all regulations, or lack of them — and all compliance, or lack of it — comes down to economic rationalism. Companies will scrimp however they can.

  47. Sean Peacock says:

    hear's an idea: store the cylinders in the shade.

  48. Vadim Yula says:

    the 240p kills me and takes me back in time.

  49. zztop3000 says:

    Hey you know what, Was this recorded with a toaster. If you have a video that's 240p, please don't even upload it to youtube, ok? It's an insult to everyone!

  50. NUCLEAR BUM says:

    as a teen i worked in a place like that i never felt comfortable around those cylinders after seeing the safety videos of how dangerous that job was i quit and moved on

  51. hay woods says:

    Everybody here is saying bad stuff well if you complain then they will charge more for it and when you get some for your grill it will be more and then you get less BBQs so dont say anything bad.

  52. Ralph Waters says:

    I live in the Los Angeles metropolitan area, and the Airgas distributor where I get my welding gases stores all their bottles upright on a flat surface with no visible support or containment. like dominoes (but less stable). We do get earthquakes in So Cal now and then… I'm kinda surprised that OSHA industry standards do not mandate some sort of restraints on these.

  53. 1FatHappyBirthday says:

    Holy tanks Batman!!!
    Yes Robin. Looks like the Joker has struck again.

  54. Strothy2 says:

    one way to ruin a good sleep, gas cylinder through the wall

  55. namibjDerEchte says:

    90 seconds. Think of how far you can walk in that time. No running.

  56. wadethewallaby2 says:

    omg TATS WERE my city is neer!

  57. Oscar Sánchez says:

    Thanks to this accident I am now dying in thermodynamics calculating the equation.

  58. look at that says:

    I live in Tulsa and watched it from less than a mile away it was crazy how far those tanks flew haha.

  59. Eric M says:

    Of course it was Praxair.

  60. Too Crash says:

    So..what was the source of ignition?..the safety valves themselves?

  61. Get-The-Lead-Out.45 says:

    The major safety violation was already known by the company and whole town before this incident even happened…
    what a bunch of careless dumb azz to allow this company to build this factory right in the middle of a town with houses that are built just 100 feet away from it, or for them to allow the houses to be built there after the factory was built

  62. TheMagnificentZoltar says:

    05:12 We will be a company selling flammable gasses. Let's call it something with "air" in the name because that sounds friendlier.

  63. 7Sin0City2 says:

    Must be summer Nelly made "Hot in Herre" from St. Louis.

Leave a Comment

Your email address will not be published. Required fields are marked *