While perusing the Internet a couple weeks ago, a hazardous materials training site I follow shared an article about a mass poisoning involving sodium fluoride back in the 1940s…
Wait whaaaaaaat? Sodium fluoride, the same stuff they put in toothpaste? This is crazy!
What’s even more crazy is the fact that I hadn’t heard about the incident, despite being kind of a geek, and a career hazardous materials technician and instructor. Interesting – the incident definitely warrants a closer look, so I’ll summarize what happened.
Flashback to November of 1942 at the Oregon State Hospital located in Salem Oregon. The hospital was serving dinner – which apparently included scrambled eggs (who doesn’t love breakfast for dinner?!). These weren’t just any eggs though, shortly after eating them, many of the patients and staff began to fall ill. Symptoms ranged from leg cramps to vomiting blood and respiratory arrest. The medical staff was completely overwhelmed, and in total 47 people died from the exposure, and 467 were sickened.
The culprit? Sodium fluoride that was inadvertently added to the egg mixture by a cook believing it was milk powder.
The sodium fluoride, which doubles as a roach-killing powder, had been stored in a cellar with food ingredients, and a well-meaning patient who was trying to assist the busy chef had grabbed it by mistake. Well that’s pretty horrifying, and, well kind of a little gross.
We still need to figure out what the deal is with sodium fluoride, so let’s take a closer look at that.
When I teach, one of the chemicals I usually reference in a hazmat technician course is hydrogen fluoride, or its cousin in solution, hydrofluoric acid (HF). As a component of many industrial cleaning and metal finishing chemicals, it is relatively common, and one of the most toxic compounds out there. When the body is exposed to HF, the fluoride ions form salts with your calcium and magnesium stores, which is generally pretty terrible for your bones and nervous system (which subsequently controls your heart).
If you’ve ever heard someone say that HF is “bad to the bone”, that’s what they are talking about – while it’s a hokey George Thorogood reference, it gets the point across.
HF is either a gas in its purest state, or a liquid in solution to form the acid, so it is relatively easy to get on you or in you if you aren’t following the proper safety precautions. Sodium fluoride is, luckily, a solid, so unless you’re having the scrambled eggs dinner special or you breathe in the dust, it is easier to prevent an accidental exposure. These poor folks were exposed through ingestion, which led to gastrointestinal corrosive injury, and many of the same effects as HF exposure.
The use of sodium fluoride as an insecticide has largely been phased out, and replaced with less toxic compounds. According to the NIOSH Guide, solid fluoride-containing compounds used as insecticide are dyed blue, to make them more recognizable and not confused with, you know, milk powder – I’m willing to bet as a result of this incident.
Back to the fact that they put this stuff in toothpaste – the same kind with cartoon characters on it that our kids use as they learn to brush their teeth. A little review of toxicology explains this pretty well. Most toothpaste formulations contain somewhere in the neighborhood of 1 mg/g of fluoride compound, but fatal toxicity in kiddos starts 16mg/kg. In other words, you’d have to eat 16 grams of toothpaste per kilogram of body weight – that’s a lot of toothpaste.
So, like most things, the poison is in the dose: a little bit of sodium fluoride is good – a lot of sodium fluoride is really awful.
Clements, K. C. (n.d.). 467 Poisoned at Oregon State Hospital. Retrieved from Salem Online History: http://www.salemhistory.net/brief_history/state_hospital_poisoning.htm
Department of Health and Human Services. (2007). NIOSH Pocket Guide to Chemical Hazards.
Johnathan Ly, M. (2017, September 5). Fluoride Toxicity. Retrieved from Medscape: https://emedicine.medscape.com/article/814774-overview#a3