Acid spill in China produces blanket of red vapor

Some dramatic images emerged from China over the weekend, after 8 tons of some sort of combination of hydrochloric, nitric, and sulfuric acid reportedly leaked from a tank at an abandoned chemical factory in Jinhua, China. Anyone have any idea what the red vapor is? It looks like the acid must be reacting with something in the sewar system.

Author: Jyllian Kemsley

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  1. Perhaps the red vapor is NO2? I thought that bottles of nitric acid turned orange because of the buildup of NO2, and the combination of acids might help generate it here. I don’t know what color nitrosyl halides are, but they might form as well. I don’t know what would happen when nitric acid hits urea, either, but it can’t be good.


  2. The red vapor could be nitrogen oxides formed from nitric acid reacting with metals, especially copper. I used to do this in my home “lab”. Wouldn’t recommend hanging around these fumes; you may not notice anything right away and drop dead a few days later.

  3. One possibility is that the brown vapor is nitrogen dioxide (NO2), from the reduction of nitric acid (HNO3). Another is that is bromine (Br2), from the oxidation of bromide ion by nitric acid.

  4. When you add HNO3 to HCl (that’s how to make aqua regia), the mixture turns bright orange within a few seconds – nothing else needed. I believe nitrosyl chloride (NOCl) and Cl2 are generated, and are responsible for the color of aqua regia. This super acidic/oxidizing solution reacts violently with organic material, generating a lot of heat, so that could help explain the fumes billowing out of the sewers. Not something you want to be close to.

  5. Note that the fellows wearing the turnout coats around all of those fumes are NOT wearing respirators.

  6. I am definitely skeptical of the news reports that say no one was hurt. No one came in direct contact with the acid, perhaps, but I would bet that anyone in the vicinity had some rather unhappy lungs.

  7. Highly concentrated nitric acid is called “red fuming nitric acid” and used in the aerospace industry in liquid propellants. It’ll make a reddish brown fume when it hits air that looks like the images from China. I would presume it’s NO2 and very nasty. Blech.