# Fire extinguisher / chemical folks: am I poisoned? **URL:** \ **Category:** Factual Questions\ **Created:** [April 21, 2003, 4:18pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060 "2003-04-21T16:18:06Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![RenMan](https://avatars.discourse-cdn.com/v4/letter/r/ecb155/32.png) [@RenMan](https://boards.straightdope.com/u/RenMan)\ **Post date:** [April 21, 2003, 4:18pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/1 "2003-04-21T16:18:06Z")
I am trying to find out if my family and I have accidentally poisoned ourselves, and don’t know it. The story: Envision a large Passover gathering, in a large rented room in my grandmother’s assisted living home. Along one wall, a buffet table of metal trays of food with a little flame underneath each one. During dinner, the air gets stuffy. Someone begins opening windows, letting in a cool April draft. One flame under a tray flickers, and begins burning higher. People gather around it, figuring out how to safely put it out. Unfortunately, the solution they come up with is to smother it with aluminum foil (which is already soaked in fat from meat). Aluminum foil ignites. Now original flame, and scrap of foil are burning underneath tray. Greasy black smoke begins rising. Family backs away. Someone runs for the fire extinguisher. POOF!! A jet of extinguishing material aimed under the tray. Powerful burst extinguishes every single flame in the row of trays. The main force was directed beneath the trays, but some of the white billowy stuff rolled foglike over the exposed food before it dissipated. Watching all this, I thought that was it for the food. Everyone had already had one pass at the buffet, so I thought we’d just throw away the rest and finish the seder and go home. To my surprise, people kept eating, and then began putting the food in plastic containers to distribute as leftovers. I myself received three containers. I seemed to be the only one who expressed anxiety about the chemicals in the extinguisher. The response I received was: “It should be ok; it’s only baking soda.” So here’s what I know: - I have no idea what kind of fire extinguisher it was. No one read the ingredients. But no one seemed worried. - I have since eaten some of my leftovers. I was not sick. Everything tasted and smelled normal. No chemical aftertaste or anything like that. So we can rule out acute poison. Nor have I heard any warning from anyone else in my family that someone got sick eating the leftovers. - This morning I looked at my own fire extinguisher (not sure if it’s the same type as was used in my grandma’s building), and saw that it contained various chemicals, including phosphate something or other. Perhaps, though, that’s just a chemical description of baking soda. My fear is: although there was nothing in the food that would cause immediate distress, is there a danger that we are introducing slow-acting, long-term toxins into our bodies, from this fire extinguisher? How can I find out for sure? ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [April 21, 2003, 4:37pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/2 "2003-04-21T16:37:22Z")
This really sounds like a C02 extinguisher in which case you have nothing to worry about. Did the extinguisher have a large, flared nozzle? That and dry chemical are the most common types but you’d know if your food was covered in potassium bacarbonate powder. ---
**Author:** ![RenMan](https://avatars.discourse-cdn.com/v4/letter/r/ecb155/32.png) [@RenMan](https://boards.straightdope.com/u/RenMan)\ **Post date:** [April 21, 2003, 4:49pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/3 "2003-04-21T16:49:24Z")
I don’t remember a large, flared nozzle. I think it was just a hose that ended abruptly, no flaring or tapering. How would I know if my food was covered in potassium bicarbonate? Color? Odor? Taste? Adverse effects from eating? Let me note at this point that I have a tendency to worry, and my worries are usually proved groundless. Still, I thought I’d check it out. ---
**Author:** ![asterion](https://avatars.discourse-cdn.com/v4/letter/a/4da419/32.png) [@asterion](https://boards.straightdope.com/u/asterion)\ **Post date:** [April 21, 2003, 4:54pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/4 "2003-04-21T16:54:33Z")
> [@](#): > > \*Originally posted by RenMan \* > \*\* > How would I know if my food was covered in potassium bicarbonate? Color? Odor? Taste? Adverse effects from eating? > \*\* Do you know what sodium bicarbonate (baking soda) looks like? It looks just about the same. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [April 21, 2003, 4:54pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/5 "2003-04-21T16:54:41Z")
FWIW no phosphorus in baking soda which is just CHNaO3 so it may have been another phosphorus compound. At any rate you have a dry chemical exintuisher which would leave lots of powder residue. ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [April 21, 2003, 4:59pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/6 "2003-04-21T16:59:18Z")
Are you saying it didn’t leave any white residue at all on the food? Then it might have been a halon, water, or carbon dioxide extinguisher. [http://www.ci.tucson.az.us/fire\_prevention/General\_Inspection\_Unit/Extinguisher\_FAQ/body\_extinguisher\_faq.html](http://www.ci.tucson.az.us/fire_prevention/General_Inspection_Unit/Extinguisher_FAQ/body_extinguisher_faq.html) > [@](#): > > Halon extinguishers contain a gas that interrupts the chemical reaction that takes place when fuels burn. These types of extinguishers are often used to protect valuable electrical equipment since they leave no residue to clean up. Halon extinguishers have a limited range, usually 4 to 6 feet. The application of Halon should be made at the base of the fire, even after the flames have been extinguished. > > Water extinguishers contain water and compressed gas and should only be used on Class A (ordinary combustibles) fires. > > Carbon Dioxide (CO2) extinguishers are most effective on Class B and C (liquids and electrical) fires. Since the gas disperses quickly, these extinguishers are only effective from 3 to 8 feet. The carbon dioxide is stored as a compressed liquid in the extinguisher; as it expands, it cools the surrounding air. The cooling will often cause ice to form around the “horn” where the gas is expelled from the extinguisher. Since the fire could re-ignite, continue to apply the agent even after the fire appears to be out. Water and CO2 are of course non-toxic. The halon used in household fire extinguishers is considered safe because it’s not very concentrated and it dissipates quickly. Halon is only toxic in heavy concentrations. [http://www.wfrfire.com/website/msds/halon.htm](http://www.wfrfire.com/website/msds/halon.htm) Under “Ingestion” it says “Not Applicable”, because it’s a gas to start with and it dissipates as soon as you squirt it. You’d need some kind of laboratory process to “ingest” it. So it wouldn’t matter if they sprayed it all over the food. If it left a white residue, then it was probably a dry chemical extinguisher. [http://ehvfc.org/extingu.htm](http://ehvfc.org/extingu.htm) > [@](#): > > These kinds of extinguishers are often referred to as multipurpose or household fire extinguishers. Extinguishers with all three (“A”, “B” and “C”) ratings are the most versatile because they are effective on ordinary combustibles such as wood, paper, plastics as well as on oil, grease, and electrical fires. Dry chemical extinguishing agents are safe for use on household electrical fires because dry chemical powder does not conduct electricity. These dry chemical extinguishers typically contain monoammonium phosphate, a powder that has properties similar to baking soda. The dry chemical powder residue acts to prevent fire re-ignition, and vacuuming or wiping with a damp cloth can clean it up. The residue from household dry chemical fire extinguishers is not toxic, otherwise they wouldn’t be sold over the counter for use in your “household”. [http://www.cargillfertilizer.com/MSDS/msdsmapp.htm](http://www.cargillfertilizer.com/MSDS/msdsmapp.htm) > [@](#): > > MATERIAL SAFETY DATA SHEET > > Monoammonium Phosphate > > Classification: Non-Toxic So, other than that, how was _your_ Easter weekend? 😃 ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [April 21, 2003, 5:00pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/7 "2003-04-21T17:00:03Z")
Did the extinguisher produce a snow like precipitate that quickly dissapeared? The pressure change of CO2 coming out of the nozzle will cause it to freeze moisture in the air. Less likely it would have been a halon extinguisher but still possible. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [April 21, 2003, 5:19pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/8 "2003-04-21T17:19:19Z")
> [@](#): > > \*Originally posted by Duck Duck Goose \* > \*\*So, other than that, how was _your_ Easter weekend? 😃 \*\* And the SDMB irony award goes to… Anyway, I hope you had a nice Passover aside from the fire and nagging doubts about toxic residue. ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [April 21, 2003, 5:25pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/9 "2003-04-21T17:25:40Z")
What “irony”? 😕 ---
**Author:** ![RenMan](https://avatars.discourse-cdn.com/v4/letter/r/ecb155/32.png) [@RenMan](https://boards.straightdope.com/u/RenMan)\ **Post date:** [April 21, 2003, 5:39pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/10 "2003-04-21T17:39:36Z")
[hijacking myself] is that irony? Just a mistake 🙂 I had a great Passover, and although I am not a Christian, my Easter weekend was nonetheless lots of fun 🙂 [/ end hijack] Well, DDG, thanks for your detailed post. That calms my fears a great deal. I’m guessing the extinguisher had to have been one of the simple types you mentioned, non-toxic in each case (except halon, and I guess it wouldn’t have been heavily concentrated. It was a less-than-one-second burst.) I suppose any truly toxic fire extinguisher (perhaps those used to put out jet or rocket fuel fires or something) would be found nowhere near a kitchen. Looks like my family and I have escaped getting a Darwin Award, at least this time!! ---
**Author:** ![RenMan](https://avatars.discourse-cdn.com/v4/letter/r/ecb155/32.png) [@RenMan](https://boards.straightdope.com/u/RenMan)\ **Post date:** [April 21, 2003, 5:41pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/11 "2003-04-21T17:41:11Z")
**Padeye** , There was a white foglike mist that rolled under and over the food trays for a brief second before completely dissipating. It was only snowlike in that it was white, but it was not divided into little snowflakes that I could tell. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [April 21, 2003, 6:03pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/12 "2003-04-21T18:03:51Z")
Pardon my 2¢ then. I always considered it ironic that _The Ten Commandments_ on TV is always billed as an Easter tradition. FWIW Jet fuel fires are treated the same as any grease fire and the same methods are empoyed. The mlitary uses foam of course but that’s really nothing more than detergent with persistent suds. A straight stream of water is avoided becuse it will just splash the fuel and of course the fire but an extended fog nozzle can reduce the flames and shield the firefighters from heat. . Dry chemical puts the fire out fast but doesn’t prevent reflash. CO2 works poorly but as you probably saw for a small fire it was adequate. Never had to put out a rocket fuel fire but considering many have their own oxidizer the best strategy is to be somewhere else as soon as possible. ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [April 21, 2003, 6:51pm UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/13 "2003-04-21T18:51:00Z")
The holiday just past is generally known as “Easter”. Wal-Mart was closed because of “Easter”. It’s perfectly appropriate to ask an American Jew, “How was your Easter weekend?” the same way it’s perfectly appropriate to ask an American atheist, “How was your Christmas?” ---
**Author:** ![RenMan](https://avatars.discourse-cdn.com/v4/letter/r/ecb155/32.png) [@RenMan](https://boards.straightdope.com/u/RenMan)\ **Post date:** [April 22, 2003, 2:43am UTC](https://boards.straightdope.com/t/fire-extinguisher-chemical-folks-am-i-poisoned/170060/14 "2003-04-22T02:43:10Z")
**Duck Duck Goose** , I didn’t realize you meant it that way. Happy Easter 🙂