Various news outlets are claiming that people suffered from poisoning after liquid nitrogen was poured into a swimming pool. The intended effect was to produce mist.

For example,the telegraph reported (text directly below the headline, above the video):

"21-year-old man was in a coma in Mexico and eight other people 
were treated in hospital after liquid nitrogen reacted 
with chlorine at a pool party ...",

This doesn't jive with my high-school level knowledge of chemistry, but I can't be 100% sure that there isn't some reaction to produce something toxic.


I totally expect that the cause of the injuries is due to asphyxiation, but I have not found a reputable source to rule out the possibility of a significant chemical reaction.

  • 1
    Seems much more likely to be en.wikipedia.org/wiki/Inert_gas_asphyxiation - 4 buckets of liquid nitrogen == a large volume of nitrogen gas
    – slim
    Jun 20, 2013 at 16:06
  • @slim Yeah, I can't watch the video but the text of the article doesn't reference anything for the claim of "nitrogen reacted with chlorine", so it may just be interpolation by the journalist. The reactions ("fainting and falling ill") are also more consistent with inert gas asphyxiation than some sort of reaction to chlorine compounds (expected reaction: "dying and screaming").
    – Tacroy
    Jun 20, 2013 at 16:20
  • 1
    @slim: Yes and, being cold, it would settle on the surface of the water. Jun 20, 2013 at 21:12

2 Answers 2


No, gaseous nitrogen (N2) does not react with chlorine. You can even buy chlorine in nitrogen, which is used for analytical purposes. If chlorine and nitrogen gas reacted, then it would be useless as an analytical standard.

A likely source of confusion is probably the reaction of chlorine with ammonia and related substances, which can result in the creation of nitrogen trichloride. But nitrogen gas and ammonia are very different molecules with completely different reactivities. This is nicely illustrated by the Haber-Bosch process, which is how ammonia is commercially produced from nitrogen gas for the use in fertilizers. This uses extremely reactive hydrogen gas, and then it still requires 150-200 bar pressure and temperatures of 350-550 °C. This should illustrate just how non-reactive nitrogen is under most conditions.


While Nitrogen will react with Chlorine to form Nitrogen Trichloride (NCl3), this reaction commonly comes from Urea in the pool reacting with the Chlorine disinfectant resulting in relatively low levels of NCl3 (which may still be hazardous to humans, but not immediately fatal).

This is made clear in this Chemistry blog post:


Updated note to media: Many outlets have reported that liquid nitrogen will react with chemicals in swimming pools to generate a poisonous gas. This is almost certainly incorrect. Molecular nitrogen is relatively inert and should not react with anything present in the pool, like “chlorine” (mostly, NaOCl) or water. The danger of adding liquid nitrogen to the pool stems simply from the nitrogen’s boiling and pushing away all of the oxygen around, leaving none for the swimmers to breathe.

  • I can't work out whether you are confirming the story or rebutting it.
    – Oddthinking
    Jun 21, 2013 at 2:14
  • He's rebutting it. Nitrogen won't react with Chlorine while in N2(which is pretty inert). The Nitrogen in Urea can react with Chlorine, but that isn't happening in this case. The main risk is the rapid boiling of liquid nitrogen into N2 gas, which then suffocates the swimmers.
    – Nick
    Jun 21, 2013 at 10:36

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