Worth mentioning that in February the EPA proposed to severely deregulate chemical facilities like the one in Garden Grove, gutting third-party audits, hazard reporting, and public transparency requirements. They titled it the ‘Common Sense Approach to Chemical Accident Prevention.’ The public comment window closed just eleven days before this disaster…
I don't think it's worth mentioning at all, since the proposal hasn't been implemented yet, yet you're trying to cause people to associate this event as somehow caused by the policies of the current administration when it's the exact opposite
I appreciate the mention of relevant and recent regulation proposals that may affect how future events like this are handled. I understand it did not cause this event but appreciate nonetheless.
To zoom out, there’s a HUGE percentage of the US who uses “common sense” as a catch-all excuse to end all discussion.
In the debates I watch, they typically don’t have the mental capacity to steel man the opposition’s position so they can’t comprehend that someone else has a different intuition / “common sense” than them.
Beyond that, “common sense” has become a dog whistle to both virtual signal / vice signal to like-minded in groups and to deride outgroups. In a way, using that phrase is a way to dehumanize the person they are talking to.
It's not like chemical spills didn't happen before these changes though. Let's not sensationalize. Can you directly link the change in policy t this leak?
I'd be curious how it came to pass that 40k people were living within the blast radius of a plant processing toxic chemicals. Isn't this sort of thing the primary justification for the existence of zoning laws?
The plant has been around since at least the 1970s. At the time it likely was on the edge of town, but through 50 years of urban sprawl, the town grew around it.
It may be even older than that. My source for the age of the site is this 1970 NASA ALSEP supplier list (from the moon program!), which lists the address as an approved manufacturer on page 38: https://www.lpi.usra.edu/lunar/ALSEP/pdf/31111000671279.pdf
Surely they've had to get new permits over time as their operations changed? And why didn't the presence of the plant prevent the town from growing around it?
There's a home 430 feet away from it. At that point you didn't even try to create a buffer zone.
Their operations have not changed very much. They have always made acrylic windshields for airplanes.
This area is zoned as an industrial park, which doesn't require buffer zones. Probably city planners at the time just thought of them as a windshield manufacturer and didn't realize the potential risks.
This attitude is why all our manufacturing moved to China.
Why is the factory's fault that people built houses right up to the edge of of the industrial site? Are you seriously suggesting they should have been shut down because people decided to build houses near an established industrial plant?
The actual site of the tank is 33.78356416377991, -117.99993897629278 [1] - its in an industrial park, and its not a large scale chemical manufacturing facility.
Its 'light manufacturing' for a company that makes custom formed acrylics for aerospace.
I get that, but the reality is that 40k people were evacuated. Shouldn't zoning be set up so as to prevent that? Light manufacturing in general is fine but it seems like these particular storage tanks might have been a bit too large for that location.
Since the plant was around long before the homes, the homes were built around it. Zoning laws, if they existed then, should have prevented the homes from building, not the plant.
California isn't notoriously hard to build in - that's a result of it being incredibly conservative - not politically, but "anything that's built can remain forever, nothing new can be built" conservative.
You’re trying to make a distinction without a difference.
It’s notoriously difficult to build here BECAUSE of NIMBYs, house values preservation, “preservation of character”, CEQA (a state law that gives LOTS of different people who shouldn’t have this power an effective veto for any new construction).
If you are worried about this incident, just wait until you hear about crude-by-rail! Crude is transported through LOTS of residential neighborhoods and zoning doesn’t matter. Additionally, railroads are governed by federal law so states / local munis can’t put additional restrictions on where, when, or speed limits.
Zoning doesn't protect people from chemicals, it protects white people from black and chinese people, and that has always been its only and avowed purpose.
Also notable that the people who live across the street from the tanks don't live in Garden Grove. By a miracle of local agency boundaries, the factory is in Garden Grove but the houses are in Stanton. Welcome to California.
Perhaps "light manufacturing" is the wrong classification for this kind of business, then. Most of their neighbors are distribution warehouses, or companies doing machining or sheet metal pressing - if you ask me those are more in line with the definition of "light manufacturing" than the 7,000 gallon runaway exothermic reaction we're seeing here.
That area has dozens of aerospace manufacturers, building up since before WW2. People wanted to live close to work. There are lots of homes and commercial areas and industrial parks are tightly mixed together.
Source: I’ve worked in aerospace in Orange County.
Because greater Los Angeles is the USA's (post-)WWII aerospace hub disguised as a megacity and cultural production center? All sorts of folks spent the 40s-00s (scientifically) blowing stuff up in the hills, and manufacturing the resulting products down in the basin and points south. Those businesses needed labor, which needed nearby housing, and here we are.
That's... not really a reasonable characterization of LA's urban growth patterns. To begin with, Hollywood quite clearly predates the aerospace buildout in the 40's and 50's. It was an oil production and refining hub before that, and an agricultural shipping center even before the dust bowl.
This particular neighborhood in Orange County certainly looks aerospacey, but I bet the Disney-centered service workers in Anaheim made up just as much of the population as the industrial folks.
Big cities are big for a bunch of reasons, basically. There are no simple answers at this scale.
As someone whose childhood home is in the evac zone ... It's a bit crazy I was living in this neighborhood my entire childhood just waiting for this to go boom
That being said California is very industry friendly and all the stuff about overregulation is from people who don't get California.
If you would like to learn more about these types of incidents, the US Chemical Safety Review Board has a fantastic series of videos on YouTube: https://www.youtube.com/user/USCSB
They explore the root causes of historical accidents. Importantly, they do it from a broad perspective: not just the chemistry, but the human factors, the decision making, and the process failures that led to the accident and how to prevent such things in the future.
Where are all of the humanoid robots? Get them in there with whatever the oil and gas industry uses for tapping pipes/containers under pressure. I'm only half kidding.
That's the same question a lot of people had during the Fukushima disaster in 2011. People were trying to contact Honda to convince them to send their ASIMO robot to shut off valves that could not be accessed by humans. That was well beyond it's capabilities. ASIMO was designed for the stage, not for a disaster zone. No one had the know-how to build such a robot.
Flash forward to today, we are still in quite the same position where robots can do fancy, flashy tech demos, but when it comes to doing something useful that is also unpredictable, the know-now is still not there. Even teleoperation is not a robust answer to this yet, it still has some maturing to do.
despite all the replace humans IT delusion, we're pretty much still the same civilization that uses steam to generate most energy. The AI emperor has no clothese.
I used to manufacture methylmethacrylate, as well as acrolein (which is often co-produced with MMA). These are among some of the more toxic chemicals currently manufactured in the USA.
Acrylates in general are truly awful. Our guys died with their faces boiling and breathing in their own vomit while also still vomiting. From a relatively brief exposure.
A bigger public risk of MMA is actually the extremely low odor threshold (in the parts per billion). The god-awful smell can make an area temporarily "unlivable" even below any known health thresholds. And it affects very large areas, because of the very low odor threshold.
Yes, I'm conflating them for dramatic effect, perhaps unfairly. If MMA is on fire, it will produce acrolein, and a lot of other chemicals as well.
I've known people who've died from both, separately, as well as ethyl acrylate and acrylic acid. I've gotten a few bursts of them in the face as well, luckily nothing too awful. I'll repeat that acrylates in general are truly awful chemicals to be exposed to.
It's neurotoxic, a respiratory irritant, and an eye irritant.
No, if it's injected in your bloodstream it won't immediately kill you, but if you inhale a few milligrams of vapor you'll wish you could cough up a lung.
Also, the vapors are heavier than air, so if you fall in a ditch near the hypothetical blown tank you would likely suffocate and die.
And then we need to consider the byproducts produced when it burns - both nominally as well as the sort of extremely dirty incomplete combustion an explosion would produce.
I live nearby, I'm hosting some family at my home who have been evacuated. A fireman friend who has been to the site said the same. That it'll either explode or spill and they're banking on it spilling.
Many people have already mentioned that officials have stated the valve isn’t working.
But also, the chemical is actively undergoing an exothermic reaction (which is why the tank is at risk for failure). How do you transport such a toxic fluid without putting much more of the public at risk?
Provided the plastic doesn't need significantly more space than the source material, of course. We all know what happens when you try freezing a sealed bottle filled with water.
I guess you ask why they are using water at ambient temperature (20°C; 68°F) instead of very cold water (0°C; 32°F). Some reasons I can think now:
They are using a lot of water, as most as possible, from pipes at whatever temperature it is. There are no enough mobile refrigerators, not enough electricity to make them work, and it's very hard to transport cold water or ice if you don't use the pipes.
Also, the center of the tank is hot and reacting, but the external part is a nasty block if plastic that acts like a shield and isolate it from the cold water outside.
This is a common problems in big chemical plants when you have exothermic reactions. It's not enough to cold it down, you need to ensure all parts are cold down.
For comparison, there is a nice video by NileRed https://www.youtube.com/watch?v=phNLecfyWS8 He is making Bakelite that is a type of plastic. It's a tiny amount, in a lab, on purpose and he may make a few attempts. Anyway it overheat and instead of a nice piece of plastic he got a nasty block of foam with burned plastic. No imagine a huge tank of a similar chemistry reaction.
The difference in cooling potential between cold water and water at ambient temperature is minimal. Cooling with water primarily comes from phase change or heat exchange; both can move vastly more heat than a small difference in temperature.
Chilling the water would massively complicate the logistics with a very marginal improvement in heat removal.
Ah, that makes sense. It's too bad they can't drill into it to relieve pressure without destroying the integrity of the tank (not that I'd want to be anywhere close to it either).
If they didn't have to worry about it imminently exploding I wonder if they could somehow wrap it with reinforcement (e.g., wrap some high strength metal around the tank to prevent it from deforming when drilled into) and then drill into it to extract the liquid?
One of my other less serious ideas was to helilift a Chernobyl style containment structure around it, but I imagine they don't have one of those just sitting around waiting to be used.
They have been doing exactly that for the past 24 hours. However the contents of the tank are polymerizing, that reaction is exothermic, and the tank is quite large.
I wonder if they’ll try drilling or shooting a hole into the bottom. A semi controlled leak to disperse it locally. A mess for sure. But better than going up and out.
I suspect it is impractical to refrigerate a large volume of water in short order. Heck, if I take 2-3 glasses of water out of my refrigerator's water dispenser, it's at tap temperature.
To put it differently, think through what it would take to refrigerate the volume of water that they are spraying. Can someone pull that together in a matter of minutes or hours?
Thank you for your interest in my emotional states, and you make a good point. However, I don't think these situations are quite the same.
In terms of population, the biggest London is 9.1 million people and the 2nd-biggest is under 500,000. Quite a big difference! I think that's why when someone says "London" one can usually reasonably assume they're talking about the one in England, unless otherwise specified (unless you live nearby).
The biggest Orange County is 3.1 million and the 2nd-biggest Orange County is 1.4 million, so the difference is not nearly as great. I'd even suggest they're in the same general category of size.
It used to say CA which is even worse.. given that's a country code (not where this Orange County is), and also means various things in other countries.. the state of California for people who live in the US, for example. What are you thinking; US-CA-OC? (We're starting to look a little ISO)
Worth mentioning that in February the EPA proposed to severely deregulate chemical facilities like the one in Garden Grove, gutting third-party audits, hazard reporting, and public transparency requirements. They titled it the ‘Common Sense Approach to Chemical Accident Prevention.’ The public comment window closed just eleven days before this disaster…
https://www.govinfo.gov/content/pkg/FR-2026-02-24/pdf/2026-0...
I don't think it's worth mentioning at all, since the proposal hasn't been implemented yet, yet you're trying to cause people to associate this event as somehow caused by the policies of the current administration when it's the exact opposite
I appreciate the mention of relevant and recent regulation proposals that may affect how future events like this are handled. I understand it did not cause this event but appreciate nonetheless.
Yeah, what this administration calls common sense is more like dumbass sense than anything else. On almost every level.
To zoom out, there’s a HUGE percentage of the US who uses “common sense” as a catch-all excuse to end all discussion.
In the debates I watch, they typically don’t have the mental capacity to steel man the opposition’s position so they can’t comprehend that someone else has a different intuition / “common sense” than them.
Beyond that, “common sense” has become a dog whistle to both virtual signal / vice signal to like-minded in groups and to deride outgroups. In a way, using that phrase is a way to dehumanize the person they are talking to.
IME “common sense” is code for “we don’t need to listen to experts about this”
It's common sense if you're trying to make more money and are a psychopath.
It's not like chemical spills didn't happen before these changes though. Let's not sensationalize. Can you directly link the change in policy t this leak?
I'd be curious how it came to pass that 40k people were living within the blast radius of a plant processing toxic chemicals. Isn't this sort of thing the primary justification for the existence of zoning laws?
The plant has been around since at least the 1970s. At the time it likely was on the edge of town, but through 50 years of urban sprawl, the town grew around it.
It may be even older than that. My source for the age of the site is this 1970 NASA ALSEP supplier list (from the moon program!), which lists the address as an approved manufacturer on page 38: https://www.lpi.usra.edu/lunar/ALSEP/pdf/31111000671279.pdf
Surely they've had to get new permits over time as their operations changed? And why didn't the presence of the plant prevent the town from growing around it?
There's a home 430 feet away from it. At that point you didn't even try to create a buffer zone.
Their operations have not changed very much. They have always made acrylic windshields for airplanes.
This area is zoned as an industrial park, which doesn't require buffer zones. Probably city planners at the time just thought of them as a windshield manufacturer and didn't realize the potential risks.
This attitude is why all our manufacturing moved to China.
Why is the factory's fault that people built houses right up to the edge of of the industrial site? Are you seriously suggesting they should have been shut down because people decided to build houses near an established industrial plant?
The actual site of the tank is 33.78356416377991, -117.99993897629278 [1] - its in an industrial park, and its not a large scale chemical manufacturing facility.
Its 'light manufacturing' for a company that makes custom formed acrylics for aerospace.
https://www.google.com/maps/place/33°47'00.8%22N+117°59'59.8...
I get that, but the reality is that 40k people were evacuated. Shouldn't zoning be set up so as to prevent that? Light manufacturing in general is fine but it seems like these particular storage tanks might have been a bit too large for that location.
> I get that, but the reality is that 40k people were evacuated. Shouldn't zoning be set up so as to prevent that?
It's funny that you would suggest this about California, where it is notoriously hard to build things.
Accidents happen, it's not obvious that this was a forseeable outcome (happy for corrections from folks who have expertise in this area).
Since the plant was around long before the homes, the homes were built around it. Zoning laws, if they existed then, should have prevented the homes from building, not the plant.
I have seen this claim (the plant was there first), but I can’t find a source.
The nearest houses were built in 1958 according to Zillow.
The earliest photo in Google Earth is 1984 and at that time the site is already totally surrounded by houses for miles.
California isn't notoriously hard to build in - that's a result of it being incredibly conservative - not politically, but "anything that's built can remain forever, nothing new can be built" conservative.
You’re trying to make a distinction without a difference.
It’s notoriously difficult to build here BECAUSE of NIMBYs, house values preservation, “preservation of character”, CEQA (a state law that gives LOTS of different people who shouldn’t have this power an effective veto for any new construction).
If you are worried about this incident, just wait until you hear about crude-by-rail! Crude is transported through LOTS of residential neighborhoods and zoning doesn’t matter. Additionally, railroads are governed by federal law so states / local munis can’t put additional restrictions on where, when, or speed limits.
Zoning doesn't protect people from chemicals, it protects white people from black and chinese people, and that has always been its only and avowed purpose.
Also notable that the people who live across the street from the tanks don't live in Garden Grove. By a miracle of local agency boundaries, the factory is in Garden Grove but the houses are in Stanton. Welcome to California.
Perhaps "light manufacturing" is the wrong classification for this kind of business, then. Most of their neighbors are distribution warehouses, or companies doing machining or sheet metal pressing - if you ask me those are more in line with the definition of "light manufacturing" than the 7,000 gallon runaway exothermic reaction we're seeing here.
That being said: https://www.ocregister.com/2026/05/22/disneyland-and-knotts-...
That area has dozens of aerospace manufacturers, building up since before WW2. People wanted to live close to work. There are lots of homes and commercial areas and industrial parks are tightly mixed together.
Source: I’ve worked in aerospace in Orange County.
Because greater Los Angeles is the USA's (post-)WWII aerospace hub disguised as a megacity and cultural production center? All sorts of folks spent the 40s-00s (scientifically) blowing stuff up in the hills, and manufacturing the resulting products down in the basin and points south. Those businesses needed labor, which needed nearby housing, and here we are.
That's... not really a reasonable characterization of LA's urban growth patterns. To begin with, Hollywood quite clearly predates the aerospace buildout in the 40's and 50's. It was an oil production and refining hub before that, and an agricultural shipping center even before the dust bowl.
This particular neighborhood in Orange County certainly looks aerospacey, but I bet the Disney-centered service workers in Anaheim made up just as much of the population as the industrial folks.
Big cities are big for a bunch of reasons, basically. There are no simple answers at this scale.
This part of the OC is very defense heavy.
As someone whose childhood home is in the evac zone ... It's a bit crazy I was living in this neighborhood my entire childhood just waiting for this to go boom
That being said California is very industry friendly and all the stuff about overregulation is from people who don't get California.
It should have been in the disclosures for all the home purchases at least, but renters don’t get those (maybe they should?)
Doesn't that mean they can bike to work there?
Imagine how often this situation lie this would be happening without institutions like OSHA or the EPA.
Stuff like this happens in Texas on a fairly regular basis, but it rarely ever makes national news.
From what I hear[1], we should be relying on the fact that environmental disasters are bad for business in a true Scotsman "free market".
[1] https://news.ycombinator.com/item?id=48238025#48240301
If you would like to learn more about these types of incidents, the US Chemical Safety Review Board has a fantastic series of videos on YouTube: https://www.youtube.com/user/USCSB
They explore the root causes of historical accidents. Importantly, they do it from a broad perspective: not just the chemistry, but the human factors, the decision making, and the process failures that led to the accident and how to prevent such things in the future.
https://en.wikipedia.org/wiki/Garden_Grove_chemical_leak
Where are all of the humanoid robots? Get them in there with whatever the oil and gas industry uses for tapping pipes/containers under pressure. I'm only half kidding.
That's the same question a lot of people had during the Fukushima disaster in 2011. People were trying to contact Honda to convince them to send their ASIMO robot to shut off valves that could not be accessed by humans. That was well beyond it's capabilities. ASIMO was designed for the stage, not for a disaster zone. No one had the know-how to build such a robot.
Flash forward to today, we are still in quite the same position where robots can do fancy, flashy tech demos, but when it comes to doing something useful that is also unpredictable, the know-now is still not there. Even teleoperation is not a robust answer to this yet, it still has some maturing to do.
It’s not simply that the tank might explode. That is one hazard, but spilling the chemical is another serious hazard.
despite all the replace humans IT delusion, we're pretty much still the same civilization that uses steam to generate most energy. The AI emperor has no clothese.
Why can’t they drill it and pipe it off into some drainage pipe for cooling or collecting in trucks?
Divide and conquer
Drill = spark = boom = nasty stuff all over surrounding area
Righti didn’t realize It was explosive like that but it really is
Flash point 2 °C (36 °F; 275 K) Autoignition temperature 435 °C (815 °F; 708 K) Explosive limits 1.7%-8.2%
Drilling is too risky then. What about dumping liquid nitrogen on the thing until it’s doused?
Inert gas?
More fire / explosion risk than the "toxic cloud engulfs city" rhetoric people have been spreading.
https://www.fishersci.com/store/msds?partNumber=AC127140100&...
I used to manufacture methylmethacrylate, as well as acrolein (which is often co-produced with MMA). These are among some of the more toxic chemicals currently manufactured in the USA.
Acrylates in general are truly awful. Our guys died with their faces boiling and breathing in their own vomit while also still vomiting. From a relatively brief exposure.
A bigger public risk of MMA is actually the extremely low odor threshold (in the parts per billion). The god-awful smell can make an area temporarily "unlivable" even below any known health thresholds. And it affects very large areas, because of the very low odor threshold.
Acrolein is about 300x more toxic than methyl methacrylate in rats. Was this unfortunate victim exposed to acrolein?
Yes, I'm conflating them for dramatic effect, perhaps unfairly. If MMA is on fire, it will produce acrolein, and a lot of other chemicals as well.
I've known people who've died from both, separately, as well as ethyl acrylate and acrylic acid. I've gotten a few bursts of them in the face as well, luckily nothing too awful. I'll repeat that acrylates in general are truly awful chemicals to be exposed to.
They talk about the possibility of a spill going into the environment, but if they know it might spill, can't they make it spill and capture it?
They are building a dam around it I read in one of the news releases maybe the one linked above
The LD50 of methyl methacrylate in rates is 7-10 g/kg. In comparison, the LD50 of table salt in rats is 3 g/kg. So it's not a highly toxic chemical.
It's neurotoxic, a respiratory irritant, and an eye irritant.
No, if it's injected in your bloodstream it won't immediately kill you, but if you inhale a few milligrams of vapor you'll wish you could cough up a lung.
Also, the vapors are heavier than air, so if you fall in a ditch near the hypothetical blown tank you would likely suffocate and die.
It is however highly flammable and potentially explosive when sealed in a tank, which is the main concern.
And then we need to consider the byproducts produced when it burns - both nominally as well as the sort of extremely dirty incomplete combustion an explosion would produce.
They say it will fail for sure, either leak or explode.
I wonder why they can't drain the tank into another facility. Maybe they just lack an appropriate container.
I live nearby, I'm hosting some family at my home who have been evacuated. A fireman friend who has been to the site said the same. That it'll either explode or spill and they're banking on it spilling.
Many people have already mentioned that officials have stated the valve isn’t working.
But also, the chemical is actively undergoing an exothermic reaction (which is why the tank is at risk for failure). How do you transport such a toxic fluid without putting much more of the public at risk?
I believe they are having issues with the valves, from what I’ve read.
But I’m just some guy.
They are having valve problems. One of the possible reasons is that it may be turning into a solid plastic.
If so, that could be one of the best outcomes. As long as it does not blow up before the process completes.
Provided the plastic doesn't need significantly more space than the source material, of course. We all know what happens when you try freezing a sealed bottle filled with water.
Yes, as of recent the third possibility mentioned by officials is that it will Turn into plastic and not explode.
The valve's jammed, so they can't really pump things in or out.
Is it not possible for them to just... spray it with ice cold water?
I guess you ask why they are using water at ambient temperature (20°C; 68°F) instead of very cold water (0°C; 32°F). Some reasons I can think now:
They are using a lot of water, as most as possible, from pipes at whatever temperature it is. There are no enough mobile refrigerators, not enough electricity to make them work, and it's very hard to transport cold water or ice if you don't use the pipes.
Also, the center of the tank is hot and reacting, but the external part is a nasty block if plastic that acts like a shield and isolate it from the cold water outside.
This is a common problems in big chemical plants when you have exothermic reactions. It's not enough to cold it down, you need to ensure all parts are cold down.
For comparison, there is a nice video by NileRed https://www.youtube.com/watch?v=phNLecfyWS8 He is making Bakelite that is a type of plastic. It's a tiny amount, in a lab, on purpose and he may make a few attempts. Anyway it overheat and instead of a nice piece of plastic he got a nasty block of foam with burned plastic. No imagine a huge tank of a similar chemistry reaction.
The difference in cooling potential between cold water and water at ambient temperature is minimal. Cooling with water primarily comes from phase change or heat exchange; both can move vastly more heat than a small difference in temperature.
Chilling the water would massively complicate the logistics with a very marginal improvement in heat removal.
Ah, that makes sense. It's too bad they can't drill into it to relieve pressure without destroying the integrity of the tank (not that I'd want to be anywhere close to it either).
If they didn't have to worry about it imminently exploding I wonder if they could somehow wrap it with reinforcement (e.g., wrap some high strength metal around the tank to prevent it from deforming when drilled into) and then drill into it to extract the liquid?
One of my other less serious ideas was to helilift a Chernobyl style containment structure around it, but I imagine they don't have one of those just sitting around waiting to be used.
They have been doing exactly that for the past 24 hours. However the contents of the tank are polymerizing, that reaction is exothermic, and the tank is quite large.
I wonder if they’ll try drilling or shooting a hole into the bottom. A semi controlled leak to disperse it locally. A mess for sure. But better than going up and out.
Both of those seem likely to risk causing sparks.
Read the article. They have been doing that, but that is just slowing things down and buying them time.
They are not. I said ice cold. I read this article and several other articles about this.
I suspect it is impractical to refrigerate a large volume of water in short order. Heck, if I take 2-3 glasses of water out of my refrigerator's water dispenser, it's at tap temperature.
To put it differently, think through what it would take to refrigerate the volume of water that they are spraying. Can someone pull that together in a matter of minutes or hours?
I love how the current title of this post just assumes that everyone lives in California.
There are other "Orange County"s in the U.S.
Do you get angry when someone mentions London that they didn't specify that it is London, England?
Because there are other Londons.
Thank you for your interest in my emotional states, and you make a good point. However, I don't think these situations are quite the same.
In terms of population, the biggest London is 9.1 million people and the 2nd-biggest is under 500,000. Quite a big difference! I think that's why when someone says "London" one can usually reasonably assume they're talking about the one in England, unless otherwise specified (unless you live nearby).
The biggest Orange County is 3.1 million and the 2nd-biggest Orange County is 1.4 million, so the difference is not nearly as great. I'd even suggest they're in the same general category of size.
It used to say CA which is even worse.. given that's a country code (not where this Orange County is), and also means various things in other countries.. the state of California for people who live in the US, for example. What are you thinking; US-CA-OC? (We're starting to look a little ISO)
Use the nearest airport code with passenger service? SNA