If you ever see this, run. Don’t film. Just run.

Is Donald Trump pope now?

Nah, he asked Marco Rubio to do the job

This looks like Nitrogen Tetroxide to me, the oxidizer used on the Titan II ICBM. Nasty stuff. Converts to Nitric Acid when in contact with moisture. Breathe this stuff and it eats your lungs out. Gruesome and painful death. Toxic exposure limit is 20 ppm. If you can see it, it is way above that limit. We called it a BFRC - big f-in red cloud that required protective to approach.

N2O4 itself is a colourless liquid - NO2 is the decomposition product. In this case the source is a nitric acid spill

In its gaseous form, it can appear reddish brown due to a portion of it having converted to NO2. Being on a Titan II launch crew 1980-84, we were trained that if you ever saw a BFRC, it was the N2O4 oxidizer. On the other hand if you didn’t see it but experienced a fishy odor it was the hydrazine blend fuel. But I am splitting hairs. You are correct and NO2 is way more common.

@peterrhague I recall the disaster plan for hydrozine (working by a highway). That stuff is beyond nasty, and nobody light a match.

Yep. Hydrazine becomes explosive in concentrations above 10000 ppm meaning a simple shock could set it off. Treatment for this situation is it lots and lots of water on it. It is also extremely toxic. Acceptable level of exposure is 0.5 ppm. And you never put water on N2O2 as that just accelerates its breakdown into red fuming nitric acid, an even more diabolical and corrosive version of NO2 due heat generated by rapid chemical decomposition. N2O2 and hydrazine make wonderful missile propellants as they ignite on contact and are fairly stable if stored and handled correctly. But lazy or stupid can change that in a heartbeat.

Nothing like a bit of NOx to help clear the lungs

It clears you OF your lungs

Looks like CURRY!

Forbidden curry

Also, if you do film, please use landscape orientation like a decent human being!

That is the smoke indicating a new you is about to be chosen

Please what is sir ?

Nitrogen dioxide. Very nasty stuff.

@akinwale_cfi Get a Windy app that shows diff pollutants in the air. People are unaware that we are exposed to this stuff in low concentrations on regular basis. Worse in some areas. And some days are worse.

@akinwale_cfi Yep. Not going to melt your lungs but can cause damage long term. ICE vehicles the big source - so hopefully it will reduce with EV adoption.

@ReadThinkTweet2 @akinwale_cfi ice vehicles? what? are you joking?

@ReadThinkTweet2 @akinwale_cfi ICE in this context means Internal Combustion Engine. I don’t blame emissions specifically on US immigration officers.

Here are The Facts 🤙🏽 Thanks for the tag @eatshrooms1 Follow to tag when a post is needing context 🤙🏽 Chemical Incident Releases Toxic Plume, Forces Evacuations in Cape Town — Montague Gardens — 2026 A chemical release at an industrial site in Montague Gardens, Cape Town, South Africa, created a visible plume of fumes on Jan. 12, 2026, afternoon, triggering evacuations and a large-scale emergency response. City officials clarified it was not a fire but linked to operations on the premises. Fire and Rescue Services located company representatives, worked to contain the plume, and evacuated affected buildings plus downwind areas. Four people were treated for exposure; one was transported to a hospital for further care. No fatalities reported. The incident remained ongoing as of late Jan. 12, per the City of Cape Town Disaster Risk Management and Fire and Rescue spokespeople.

I worked at a Dow chemical plant doing industrial insulation in 1994. During my safety training it concluded “If you see people running, spot the wind flags and run upwind!” They had around the chemical plant flag posts with triangle flags. You run the opposite way they point.

Additional info: DO NOT RUN DOWNWIND!

BFRC!

is that hydrazine?

Nitrogen Dioxide. Even nastier than hydrazine

Brown cloud means either bromine or NO2 (or NO2 from NO4 as you point out here). Bromine burns flesh, respiratory tract. Lethal dose is 3ppm. NO2 50% lethal dose is 174ppm over an hour.

If you ever see that color anywhere don’t buy/wear/touch/eat/breathe it

It's only a mixture of nitrogen and oxygen, just like air

What if I'm filming from inside my Tesla and I have biohazard mode turned on 🙃

Hydrazine?

Nitrogen dioxide - in this case from a nitric acid spill, but you get the same cloud from nitrogen tetroxide.

@Barrie_Tite @grok what happens if you’re exposed to this

Exposure to nitrogen dioxide (NO2), like in that cloud, irritates the eyes, nose, and throat. It can cause coughing, wheezing, shortness of breath, and reduced lung function. High levels may lead to severe respiratory damage, pulmonary edema, or death. Evacuate and seek medical help if exposed. Sources: CDC, WHO.

Yup

I remember generating it by mistake in a chemistry lab. I don't remember what I did, but roughly it was nitric acid drops on some metal powder, probably copper, zinc or iron. But that's the color. Like honey.

These two inhaled it in Breaking Bad

Orange cloud?! Might be sarin, or even mustard gas. Gtfo there!

Wrong recipe at the Huy Fong Sriracha factory?

Looks like chlorine so deffo

Nitrogen dioxide, from a nitric acid spill

And thanks still not nice to breathe in at all

Any colored smoke just GTFO

Holy moly... that's a massive nitric acid spill? releasing nitrogen dioxide. It is a severe respiratory irritant.

Remember the rule of thumb! 😬 Acid leak = RUN!!!

My initial thought was bromine but no cloud that colour is safe to hang around!

Here’s what Grok said about it: People standing around filming instead of fleeing is unfortunately common in the age of smartphones — shock, disbelief, or thinking it's "just smoke" or something less dangerous plays a big role. But with NO₂, that instinct can be deadly because: - The gas has a delayed toxicity (as I mentioned before): You might feel only mild irritation at first (coughing, burning eyes/throat), inhale a lot without realizing the severity, then feel okay for hours... only for severe lung inflammation and fluid buildup (pulmonary edema) to hit later, sometimes fatally. - At accident-scale releases (hundreds to thousands of ppm), it can overwhelm people quickly: choking, chest pain, dizziness, collapse, and in extreme cases, rapid death from asphyxiation or methemoglobinemia (where blood can't carry oxygen properly). - Being downwind/low-lying is worst — the cloud settles and concentrates there. In short, if you ever see a large, colored gas cloud like that (especially reddish-brown, not white/gray smoke), the safest move is immediate evacuation upwind — no filming, no waiting to see what happens. Emergency responders treat these as hazmat incidents for good reason, with evacuation zones measured in miles sometimes. Knowledge like this can literally save lives, so thanks for asking

Judging by the color of that smoke, I’m definitely not going to stick around for long.

Normal flame is orange, normal smoke is black, brown or white. Any variation should have you running. 20yr hazmat tech here, and still brown flame or orange smoke makes the monkey part of my brain go berserk.

I definitely recognize that color — nitrogen dioxide. Definitely run.

N2O = fun and games NO2 = toxic death cloud

My cousin was a train engineer. He told me that is a train wrecks to leave the area immediately. He said not to stick around and watch. Many of the chemicals are dangerous.

God damn it Jesseeee 😂

Yeah, orange smoke is always bad news