As has been widely reported this week, organizers of a pool party in Mexico, hosted by the drink company Jägermeister, decided that they could enhance the experience by creating a cloud of fog to drift over the water. The method they chose was pouring the contents of four containers of liquid nitrogen into the pool. The resulting "fog" sent nine people to the hospital, one of whom remains in a coma.
"For no doubt the first time ever, a bad decision was made at a pool party sponsored by Jägermeister ," noted science writer Ian Chant of Geekosystem sarcastically. As usual, Chant tells the story in a clear and lively fashion but he also – and this was what caught my attention – notes that the chemistry of that fog had been widely misreported. To quote:
"According to chemistry blog ChemBark, what happened at the party was not a chemical reaction between chlorine in the pool and nitrogen as is being reported elsewhere. Nitrogen is pretty inert, and shouldn’t have a major reaction with anything in the pool. Instead, chemist Paul Bracher explains that the liquid nitrogen boiled off after being poured into the pool, expanding quickly and displacing the oxygen around the pool. That meant that pretty soon, everyone in the pool was attempting to breathe nitrogen instead of oxygen…". As he noted, this is not a healthy substitution.
Naturally, I then took a look at the ChemBark post, which is titled: "Awful Idea: Liquid Nitrogen at a Pool Party." On a note of exasperation, it contains this message to journalists:
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.
You'll also find there a list of media outlets which incorrectly reported on a toxic cloud generated by a nitrogen-chlorine reaction – and outlets that got it right. As the International Science Times reported, Mexican officials first explained the incident as due to that nitrogen-chlorine reaction. And although chemists like Bracher have worked to correct it, the result was a ripple effect. Some corrected the information – my favorite of these, is the Latin Rapper website, which made a careful point of getting it right. Others did not correct: the British newspaper, the Daily Mail, for instance, kept it wrong. MSN Now kept it wrong.
It's unrealistic, of course, to expect editors in a hurry to hover over their chemistry explanations in a story of a poisonous pool party. But I bring it up because without such corrections, it is realistic – predictable, even – to see such misinformation spread further. Today, for instance, Slate told the story and, yes, got the chemistry wrong again.
Most journalists, of course, don't know chemistry well enough to have caught this mistake on the fly. But as a recommendation: in cases like these just a few minutes of extra homework will make that lack of knowledge less obvious.
— Deborah Blum
UPDATE: After I wrote this post – and I like to think in response to it – a couple of the problematic stories were corrected. The Mail removed the nitrogen-chlorine reaction. As did Slate. Although, as one person wrote me on Twitter: Did you see @slate's correction to pool story? Took out rxn with chlorine but still calls nitrogen "toxic cloud". So let's call it a work in progress.
[…] urinate in a swimming pool. This harmful chemical is formed when the chlorine found in the swimming pool reacts with nitrogen, a constituent of urine. This chemical acts like tear gas. I don’t know if you have had any […]