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Given the disruption this has caused in Orange County I would expect to eventually get a slick US Chemical Safety Board video on it.

Now I'm thinking that a weak part of the tank gave way at one of the lesser welds on this non-pressure vessel, quite early and in the top part of the tank well above the liquid level. When you stand on top of a big tank, a lot of them do flex quite a bit. Physical pressure must have increased somehow in a way that could not be relieved without rupture.

IIRC there was some report of a "gas leak" to begin with and that could very well have been it.

I can only imagine what it's like to be one of the shift operators down there on the pavement around the tanks and pipes on a daily basis, in their flame-retardant coveralls and hardhats. Based on my vivid experience working with similar operators as I took official samples from tanks usually located in much bigger tank farms.

MMA smells so sharp that any leakage from a valve or pipe fitting gets attention much more so than other flammable liquids, for instance things like paint removers, alcohol or acetone which smell very faint by comparison. I expect that the workers had gotten accustomed to a fairly clean air environment without serious toxicity levels, and would estimate that a leak of about 1 drop per minute from a flange would be easily identified and fixed. Not only to keep the neighbors from complaining, but to keep the workers from gagging when they walk closer to that location.

If the first sign of trouble was physical tank bulging and/or suddenly stinking up the whole place with lots of MMA vapor (like from an upper tank rupture) when there is no sign of leakage on the ground, that pretty much qualifies as a "gas leak". Once the smell was no longer prominent, I would say that polymerization was well underway and there was not as much free monomer available to build up more pressure or even evaporate very much after that. If there's warm liquid MMA open to the atmosphere, you will smell it downwind.

It might be a stretch to say that "nature takes its course" when synthetic monomers spontaneously polymerize like this, but that's what some of them do best that sets them apart.

From what I understand, in the uninhibited pure monomer it doesn't take that many PPM of monomer molecules to become "activated" in some way before the chain reaction of them with remaining molecules eventually accelerates to completion. Which may be why such a low concentration of inhibitor works so well, but inhibitor must be well-dispersed within the liquid and there must be enough circulation to avoid local depletion of the inhibitor due to stagnant contact with as yet unidentified unexpected initiators. Not only should it be easy to get a random 1 liter sample from a tank (of such non-viscous material) at any time, the single sample should ideally be highly representative of the entire tank contents. Due to the way the liquid is handled in bulk going in & out of the tank, as well as any additional circulation to insure good mixing of incoming cargo, or after boosting inhibitor amounts when only a few carefully measured pounds or kilos of the concentrated inhibitor is dumped into the bulk monomer to keep it from going below spec.

The inhibitors have been selected to be very strong and effective at what they do so it doesn't require a high concentration, and the downstream processors can more easily overcome the inhibitor effect and produce plastics using different and milder polymerization initiator techniques when there is not an excess of inhibitor.

Once it gets polymerizing past that minuscule little inhibitor, from that point it's like there is no inhibitor at all. So there is some possibility that this is a fairly worst-case runaway polymerization event where the full amount of caution was rightfully warranted. Even though it would have to be considered fairly benign compared to a whole tank of the liquid monomer dispersing through the neighborhoods, or going up in a fireball, which is always a risk anyway :\

Under storage, it really is tremendous force that the inhibitor is holding back, considering how badly outnumbered it is by the 99.9% of everything else in the tank that wants to spontaneously react with itself otherwise. When the inhibitor is only about 20 PPM, which in percent is 0.0020%, in these cases percent by weight. IOW 20 lbs of MEHQ crystals dissolved in every million lbs of MMA liquid, or in metric 20 kilos of inhibitor for every million kilos of cargo.

Now usually the lowest inhibitor concentration will be at the chemical plant that produces the monomers, and it may go into bulk storage the same way when fresh material is moving through the system adequately. From there, vessels, rail cars and trailers often have different amounts of additional inhibitor added in order to boost levels according to purchase agreements of the different industrial consumers.

Often by contractors such as companies I have worked for who store the inhibitor concentrate as agents for the client, and can sample industrial tanks & test in the lab to routinely determine inhibitor concentration. Then carefully measure according to requirements and be the third party that certifies the new concentration after our field operator physically adds the additional dose to the tank.

For something like vessels and rail cars you just can't expect their cargo samples to accurately reflect a recently boosted inhibitor value, the small amount of inhibitor concentrate won't be adequately mixed with the rest of the bulk monomer before the ship leaves the dock or the train leaves the terminal. So it has to be certified by careful physical addition while being supported by good lab data to begin with. You expect lab readings to match the certificate after the ship gets overseas or the rail car gets across the country.

Now measuring low PPM is not always easy but you get better after a while.

Much better for me because I got to start doing it my own way as soon as I could, after first establishing as many of the predecessor techniques as possible for reference, but people still wanted more reliable results and so did I since the beginning. Ever since then, doing the continuous improvement thing for more decades than you normally get.

Things I will work with, repeatedly ;)

Based on the article, the inhibitor chemicals _are_ the passive protection system, they just can't be perfect because too much of that stuff ruins the purpose for having the chemical in the first place.

I believe they tried to inject some chemicals to slow the reaction, but the pump and/or valves failed and clogged.

Why? For the same reason our reactors do not have containment buildings around them, like those in the West. For the same reason we don't use properly enriched fuel in our cores. For the same reason we are the only nation that builds water-cooled, graphite-moderated reactors with a positive void coefficient.

It's cheaper.

> Why wouldn't there be passive protection systems designed in?

Because the US chemical industry has been effectively unregulated for a century and can do whatever it pleases.

There's a neutralizing chemical that could have been injected to stop the exothermic reaction in its tracks. They didn't have it on site. A "response team" (likely a contractor that responds to chemical emergencies) did, but by the time they showed up, supposedly things were too damaged to inject it. That neutralizer should have been a Big Red Switch away.

They also should have had a deluge system, for example, to cool the tank. With a standpipe for firefighters if there's no water available onsite. Was there? Nope! No requirement for it. Despite the dangers of this stuff being very well documented, it having caused disasters before, etc.

Consider that the chemical industry can invent a new chemical and the onus is on everyone else to prove it is hazardous. So what does the US chemical industry do? Spend lots of time "innovating" new versions of chemicals to constantly leverage the 'innocent until proven guilty' scam. Chemical A is found to be cancerous, so they rework it slightly, enough to call it a new chemical even though it's nearly the exact same thing, but we're right back to square one on it "not being hazardous."

Protection systems cost money. If something really bad happens the cost of the disaster far outweighs whatever assets the company has hanging around, and in the US, we basically never hold anybody responsible for what they do in the course of their job running a corporation. GM willfully ignored problems with Chevy Cruze ignition switches that caused countless people to die because they'd randomly shut off _and shutting off meant the airbags would get disabled_. Did anyone in those teams, or their managers, ever get held accountable? Nope, not except in some civil suits, where Chevy repeatedly claimed they didn't have any documentation. Well, at some point Congress went after them for something, and in the massive pile of documents lo and behold there wer piles and piles and piles of documentation about the ignition switch issues.

A company like that isn't even required to carry a lick of insurance, far as I'm aware. Meanwhile, and I wish I were joking on this - if I want to get a permit to set aside space in front of my apartment building to park a moving truck, I have to carry a million dollars insurance that protects the city.

If I park my car blocking an ambulance I get charged with at least one crime, possibly even manslaughter or homicide. Ditto for blocking a fire truck trying to get to a fire. A railroad can do it to half a county, dozens of times a year, and everyone just shrugs as people are harmed or killed, or half a neighborhood burned down. All because private equity is milking the railroad so tight that it's making trains that are miles long instead of lengths that are appropriate for the tracks they're on and won't block fire trucks, ambulances, police cars, school busses, and the general population as a whole.

The free license corporate America gets to shit all over society has got to stop.

World's largest Outstanding Service Award.

https://media.springernature.com/lw685/springer-static/image...

So... maybe?

Ooh, like when a bottle of Krazy Glue dries out? I kinda hope so...

Transparent Aluminum

And for what, $25.00 bucks an hour? We need to take back production.

It seems like the issue wasn't the pressure so much, but the temperature. The contents were supposed to be stored at 50 degrees. The thermometer for the tank was reading 100 degrees, but nobody knew what the actual temperature was, because the thermometer's maximum reading was 100. So the challenge was to figure out how to cool things down (which would relieve the pressure in turn)

First, there's probably a pressure relief system already on the tank.

The problem is that is analogous to drilling a hole in a pressure cooker, it's either going to rupture the tank entirely, or blast the contents into the air.

Also curious where you would get a "quadcopter with a small drilling machine" with a couple hours' notice; even if you had one, it would be hard to maintain a position at one exact spot, and much of the lift energy would be expended in the torque reaction of the drill.

All process tanks I've seen have various cleanout hatches, drain valves, pressure relief blowoff valves... even your water heater has these. Not sure about this tank in particular and obviously there were no easy answers in this particular event, but hopefully lessons will be learned.

If you shoot and pierce a vessel that is pressurised, especially if it’s near its pressure limit anyway, it will explode. Even if it’s just filled with an inert gas.

Actually even just making a hole by any means will significantly increase the chances of an explosion. This because the smallest crack can start a chain reaction where the material at the leading edge of the crack is bearing too much stress and the bonds break which then passes the stress on to the material straight after that. This all happens very quickly and can even accelerate as the hole grows bigger and gas starts moving.

It’s very lucky that the crack that formed didn’t propagate like that. It could be for many reasons though, like the crack front could have run into thicker material or a weld line or something like that and if luckily stopped the crack.

Not a direct answer, but there is a standard code for what actions emergency services should take, and the code[1] for this stuff is 3YE, which means "Use foam or dry agent, substance reacts violently/is explosive, BA [breathing apparatus] use is essential, evacuate vicinity, contain spill." So there must be some reason not to let the stuff out.

[1] This is the hazchem code. I think the US uses a different system. A list is here: https://www.ricardo.com/media/radn55jg/dangerous-goods-emerg...

The spark could have caused an explosion.

Wait... how could that have helped? It's a toxic material under pressure so why would we want to vent it further?

I guess that begs the next point though - the high pressure system inside would want to violently vent out to the low pressure system outside through the relatively tiny hole.

Delta P... when it's got you... it's got you.

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BLEVE = Boiling Liquid Expanding Vapor Explosion

> A leak was detected in one of the fittings and an attempt was made to correct it by striking the fitting with a large wrench.

Why bring God into the discussion? Do you think he’s monitoring our lives actively? Why is he a he? Does God have male genitalia?

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I thought Trump defunded them last year? It was big news at the time.

On the plus side, it's a chemical that was discovered more than a century ago so scientists have accumulated a lot of knowledge about it. So far no studies were able to link it to cancer. It also doesn't significantly build up in the body over time (like heavy metals do). It's 3x heavier than air so it shouldn't spread too far away. The main issue is they want to try to keep it from getting into storm drains or into the ground water.

I've heard from others that it's readily absorbed by water. That's bad in the ground water case, but it seems it might be a positive when trying to clean up a (contained) spill.

It appears to me to have a relatively high lethal dosage (my back of the napkin calculations are saying a 200 pound human would have to orally ingest almost a liter of it to reach the LD50 dosage--but again don't quote me on that number because I am not an expert and could have very easily messed up the math or the concept of a lethal dose).

So, while I agree there might be unknown long term issues, it does appear to be a relatively low probability of that since it seems to be on the less pernicious side.

It probably polymerized completely and it's a giant block of nasty looking solid plastic, that perhaps can be lifted with a crane (with some support, in case it has cracks or something).

In some plastics the monomer is toxic, but the polymerized form is safe. (I think it was use for windshields for planes, so once polymerized it was probably safe to touch at least.)

In this case it was an uncontrolled reaction so I'm not sure if someone knows the exact current composition of the goo, so I strongly recommend to avoid licking it.

MMA is not very toxic. It has the same LD50 as vitamin C. Table salt and baking soda are twice as toxic as MMA, for example.

Additionally it is almost certainly not in vapor form at 100 degrees. In sunlight it will also polymerize to a solid pretty quickly.

As such you'd practically have to drink it inside to hit the ld50.

The explosion would be much worse than a release of liquid or vapor based MMA during the day, and here it almost certainly solidified at this point

> insanely toxic

Some quick searching suggests that it’s toxic but not even close to “insanely toxic”. And it’s not persistent in the environment.

If you want a genuinely nasty chemical, check out methyl isocyanate, which is some two orders of magnitude more acutely toxic.

Opened a small round bottom flask of this when I worked in the lab. Closed it immediately when I felt burning in my eyes as did others around me.

It’s toxic but not insanely toxic. Isocyanates, phosgene, gaseous cyanides - now those are insanely toxic

> What a disaster and complete failure on the local government in the way they handled this situation.

Can you expand on that? It seems like there wasn't a lot they could do once the tank started leaking.

> it has been extremely frustrating getting updates via xitter. Do we really have no other options?

It is amazing how the modern world has a webpage for every organisation but they can't bloody update it usefully and use a random platform (Xitter, Mastodon, Bluesky, facebook) instead.

vague post