# OAV, putting the risk in perspective



## Jack Grimshaw (Feb 10, 2001)

Always enjoy reading Dick's post on BEE-L and usually learn something new.Rather than trying to glean information from" the opinions of others",it is best to know of and listen to the experts.

Here is a brief bio from a talk he gave at Greater Cleveland B.A.

Dr. Richard Cryberg, Organic Chemist, Researcher, Beekeeper

Dr. Richard Cryberg received his BS in Chemistry from Iowa State University and his PhD in Organic Chemistry from The Ohio State University. He had a long career in research and development with Diamond Shamrock Crop. and successor companies.

Dr. Cryberg was a beekeeper for a decade in the 1970’s and returned to beekeeping in 2005. He comments, “The difference between my first experience and today is striking due to the massive impact varroa mites have on what is required to keep a hive alive today.”


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## GregB (Dec 26, 2017)

I would not bother talking of lethality of the OA if consumed internally.
OA-containing veg are a staple in my house.
So, next....

However, incremental damage to your air ways is a consideration.
So, I worked with harsh chems (acids and caustics and bleach) - cleaning the food plant equipment, while getting through college.
In all I worked with the chems 1-2 nights per week. Usually two nights.
We used industrial-grade protection. It was required by OSHA.
The entire gig lasted between one and two years.

So now, more than 20 years later I maybe feeling it.
It appears those marginal damages I incurred to my air ways are catching up with me.
This is very unpleasant and the longer term outcome is not known.
This is impossible to prove - of course, and very convenient so to those potentially responsible (not to me; to me the issues are rather inconvenient).

Pretty much, if the thing does not kill you on the spot - it very well may kill you 20 years later and slowly.
So, that is a consideration for those practicing fumigation.
Do protect yourself in the best possible ways.
Do question the practice itself too - is it worth it to you.
No one will give you any guaranties and take enforceable responsibilities onto themselves (let them be PhD in chem).


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## squarepeg (Jul 9, 2010)

i noticed this correction posted in that same thread today by a belgium beekeeper:

"I'm sorry but it isn't so that in Europe 'everyone treats his/her colonies freely with OAV in the presence of honey to harvest', on the contrary it is strongly discouraged by all official authorities!"

https://community.lsoft.com/scripts/wa-LSOFTDONATIONS.exe?A2=1911&L=BEE-L&D=0&P=70822961

perhaps the u.s. label regarding oav will change some day but for now the law is clear that honey supers are to be 'removed'.


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## Biermann (May 31, 2015)

Personal *safety* is *no accident*! Be careful Ladies & Gentlemen!

Treating with the supers off should be a standard, why risk problems if it can be easily avoided.


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## JWPalmer (May 1, 2017)

My point in posting this was not to open the supers on/ supers off debate, AGAIN. Rather, to alleviate the fears of those who do treat with OA. It is almost impossible to get a lethal dose of OA from treating, whether by inhalation of the OA during treatment, or by ingestion of honey that perhaps was in the brood comb and later harvested for your own PERSONAL consumption.

The current law is to remove supers and is not "optional".


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## squarepeg (Jul 9, 2010)

with respect to inhalation the problem is not so much achieving a lethal dose but rather the extreme corrosive nature of the acid and it's ability to instantly damage lung tissue. 

i.e. no skimping on having a quality respirator and goggles or consider following randy oliver's lead on not risking exposure to the vapor and utilize alternative delivery methods instead.

https://www.ontariobee.com/sites/ontariobee.com/files/document/OA safety.pdf


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## HarryVanderpool (Apr 11, 2005)

Grainger has a sale on OG / acid gas canisters for Honeywell North respirators for $11.70 a pair.
I bought 8 pair.
Seems like my lungs are worth at least that much.


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## Robert Holcombe (Oct 10, 2019)

JWPalmer, Couple of points worth noting, I think, based on my research efforts:

1. US EPA approval is based on the Canadian Label. After an extensive search I gave up on trying to find the basis or why for the "super off". Best I can tell it was simply added without explanation for risk avoidance. The Canadians had a lot of EU data, especially From Germany and Italy to support an alternate decision. Yet no explanation was provided that I could find. The EU, I believe, controls organic acid treatment affects on honey by measuring total acidity unlike the USA which has no technical standard for honey. One testing problem it seems is the organic acid data is swamped by Formic acid effects. Treating with "supers off" for any OA treatment simply avoids the issue contamination possibilities.

2. I have yet to see any US or Canadian analytical data based on half life characteristics of oxalic acid, rather short, nor how ubiquitous it is in the environment and it's use by the farming community. One only has to ask who is using all that oxalic acid produced yearly. How does it affect us as notd by the EPA fiel data related to the approval

3. What should really be highlighted when handling oxalic acid, I think, is the risk to your eyes. I worked in a chemical plant, 50% caustic ( NaOH), phosphoric pentoxide, chlorine generating reactions, mild acids, strong acids, pippet sampling, etcetera when I was in high school and several periods when I was in college. I have used oxalic acid since I was about 11 or 12 as a cleaning solution. Thus I learned to use OAV with caution and no fear. I also keep a bucket of water with me at all times (missing from the label) with a wet wrag. I also use it to clean of granular OA if it should get on my skin or hive as I would for any significant acidic or caustic product. I follow the EPA label and have a IPM program that works well for me and meets the EPA requirements. I admit to forgetting my "official" 1/2 face mask filter often but I do have a hood on and do know how to hold my breath 

4. What I found interesting is the lack of specified requirements for a "1/2 mask filter" specified by the EPA. A handkerchief? A wet handkerchief? Selection is left up to the user, most of whom are not corporations with "safety experts", thus do not have a clue. Try pulling that thread and reading the OSHA requirements to get a derived answer. I do my bring my filter with me, when I remember, my 1/2 face-mask filter, which I use religiously for cutting wood and other projects. I like to multi-purpose everything.

5. I give my honey to my grandchildren.


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## little_john (Aug 4, 2014)

Just want to add my 2 penn'orth to this ...

The figures often cited (X mg/litre of air etc) by Health & Safety organisations may be appropriate inside a building, where any contamination will be constant enough to take a reasonably representative measurement. (although undoubtedly when measuring airborne dust there will be variations at different heights and at different distances from the source, as well as at different times of day)

But I'm going to suggest that H&S figures for Oxalic Acid are inappropriate as a reference when the substance is being used outdoors by beekeepers, as the volume of air which the dust momentarily contaminates is - for all intents and purposes - infinite.

If a sensor were to be placed into a plume of OA dust exiting a hive, then the readings would dramatically exceed those of the legislation, whereas if a sensor were to be placed a foot or two to one side of the plume, or upwind, it would most likely register a complete absence of OA dust in the atmosphere.

The presence of OA dust during VOA treatment is both transitory and directional - and yet people will keep banging on about safe H&S limits - and recommended mask types - which are intended for guidance within a confined working area.

To be sure, Oxalic Acid is a dangerous substance if used without due respect - but then so are many other chemicals we use in our everyday lives. Far more people drown in water every year than are even mildly affected by airborne Oxalic Acid dust, and yet I bet there's no MSDS data sheet for water ...

LJ


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## Robert Holcombe (Oct 10, 2019)

LJ, Love the reply's logic! With a touch of sanity added. I believe there is a German safety report out for just that application, OAV outdoors. I believe it concluded that it was "safe" or within risk standards. Unfortunately, maybe fortunately for some, there are different legal and liability standards in England, EU and the USA. 

Do you have a reference for calling the escaping OAV product leaking from a hive is "Oxalic Acid dust"?


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## msl (Sep 6, 2016)

> yet I bet there's no MSDS data sheet for water


https://www.spectrumchemical.com/MSDS/LC26750.pdf
:lookout::ws:



> The presence of OA dust during VOA treatment is both transitory and directional - and yet people will keep banging on about safe H&S limits - and recommended mask types - which are intended for guidance within a confined working area


Well the exposure limits are advraged... they work out to 3.3 mg per shift(1mg per M3, 7 L of air breathed per min, 8 hours) 
the shorut term limit is 2mg per M3... 
with a band heater type set up your putting out 4,000 mg a min!
not hard to go over the limits and then some with even a quick breath, and yes as the cloud is well over the STEL you should be following the safety recommendations. We are dealing in constrations massively about the safety limits


this is less of an issue with a wand type that is placed cold, turned on and you walk away. But with hand held units its quite possibly to take a face full 



> Do you have a reference for calling the escaping OAV product leaking from a hive is "Oxalic Acid dust"


why would it not be?
you heated a solid and it sublimed in to a gas, as soon as it cools below sublime temp it forms a sold again.


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## JWPalmer (May 1, 2017)

From the above referenced safety data sheet for water. Another example of the lunacy sometimes found in a SDS.



> First-aid measures after skin contact :
> 
> Remove affected clothing and wash all exposed skin area with mild soap and water, followed by
> warm water rinse. Adverse effects not expected from this product.


Where else would you find the first aid for exposure to a product to be to liberally drench yourself with more of the same product?


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## crofter (May 5, 2011)

JWPalmer said:


> From the above referenced safety data sheet for water. Another example of the lunacy sometimes found in a SDS.
> 
> 
> 
> Where else would you find the first aid for exposure to a product to be to liberally drench yourself with more of the same product?


Oh that one is well known. We used to call it "hair of the dog that bit you"


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## little_john (Aug 4, 2014)

JWPalmer said:


> Where else would you find the first aid for exposure to a product to be to liberally drench yourself with more of the same product?


Along a similar line ...

One of the most common 'magic bullets' these days for headaches is Ibuprofen ... but one of Ibuprofen's side effects is ... yes, you've guessed: headaches.

So you have a headache. Take a Ibuprofen tablet and get another headache - and so take yet another tablet ... and so on. Crazy.
LJ


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## username00101 (Apr 17, 2019)

JWPalmer said:


> The following was posted by Dr. Richard Cryberg on Bee-L. I received his permission to repost it in it's entirety here. You may draw your own conclusions, but I personally agree with the premise. The cough from chlorine gas exposure is way worse ( see reference below). Imagine trying to cough up a lung while an elephant is sitting on your chest...JWP.
> 
> 
> 
> ...


Sounds similar to a previous thread here on beesource which did similar math, indicating that OAV is perfectly safe to use with honey supers present. 


https://www.beesource.com/forums/showthread.php?356975-OA-vaporization-is-probably-safe-with-honey-supers-here-s-my-calculations

IIRC there was quite a bit of good discussion, and other members offering their own calculations, coming to similar conclusions about the harmlessness of OAV to honey.

Eventually, that thread was censored, as a result of quite a bit of hubbub from the "lawfully minded".


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## Cloverdale (Mar 26, 2012)

JWPalmer said:


> My point in posting this was not to open the supers on/ supers off debate, AGAIN. Rather, to alleviate the fears of those who do treat with OA. It is almost impossible to get a lethal dose of OA from treating, whether by inhalation of the OA during treatment, or by ingestion of honey that perhaps was in the brood comb and later harvested for your own PERSONAL consumption.
> 
> The current law is to remove supers and is not "optional".


As you stated on bee-l on why you wanted to post this, at least you tried! 
Deb


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## username00101 (Apr 17, 2019)

Cloverdale said:


> As you stated on bee-l on why you wanted to post this, at least you tried!
> Deb


The current "law" only exists in the US and Canada.

Elsewhere, OAV with honey supers present isn't against the law. It's only "discouraged".

I feel that it's important to make that clear.


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## A Novice (Sep 15, 2019)

For the beekeeper, it seems to me the danger from oxalic acid is due to direct chemical damage to tissues, as opposed to chemical toxicity.

Mostly, this is the eyes and the lungs.

It is hard to get the relatively large amounts needed to cause a toxicity problem. A good sized helping of spinach has more oxalic acid that you put in your vaporizer, and only a very small part of what goes in the vaporizer is likely to end up in your lungs.

I don't know how well lungs recover from chemical burns. I do know that if you breathe a little of that "smoke" it is unpleasant and you can feel it for at least a day or two afterward.

Having relatives who experienced diminished lung capacity as they grew older, I think it is a good idea to protect my lungs

I would like to see data on oxalic acid absorption in honey supers when hives are treated with supers on. I suspect it would be quite low. 

I read on Randy Oliver's page (or a link to a link from there) that

if there is 400 mg/Kg oxalic acid in honey, you can just taste it.

Oxalic acid in honey is naturally occurring, and ranges from 5 to 300 mg/Kg. Honeydew honeys tend to be higher in oxalic acid than floral honeys.

The median value of oxalic acid in honey is about 20 mg/kg. (not sure about that number)

I suspect that honey in the hive gains very little oxalic acid due to vaporization. 

Oxalic acid crystals precipitate out of the air on surfaces in the hive. If they do this uniformly, a typical hive (2 deeps, 2 supers) has about 14000 square inches of internal surface area. about 3000 of that is the comb area in the two supers. (those are my calculations, you can check it to see if it seems accurate). 

Any acid which precipitates on way is likely to be cleaned out of the hive by the bees. This is my understanding of how it works. So the only area of interest is where there are combs full of honey or nectar which are not capped. I will guess that is about half of the 3000 square inches of comb surface in the supers. 

This neglects the surface area of the bees themselves, which is considerable. a honeybee is hairy, and as a result has a surface area of about 16 square inches (between 10 and 25). the 30000 bees in a typical hive have a surface area of probably 480000 square inches. (has anyone else seen the slightly white bees that I see sometimes after vaporizing?) Forgetting about that (and it is significant) The amount of oxalic acid in the honey after a vaporization is probably not more than 2g * 3000 * (1/2)/14000 = .21g = 210 mg.

The two supers in this case should yield about 30 kg of honey. So the concentration increase should be 210 mg/30 kg = 7 mg/kg.

Compared to the amount of oxalic acid in honey already, this increase would not be significant.

This of course is armchair science, not the sort used to make decisions; except what sorts of things to investigate.

It is likely that most of the oxalic acid crystals are on the bees themselves - how much of the crystals from the bees end up in the honey is anyone's guess.

However, it looks to me like some research related to oxalic acid in honey as a result of vaporization would be useful. Not being able to use OA (practically speaking) during the honey flow is a real limitation.

In the short term, don't use OA vaporizers with supers on. It is not legal. However, if I had some honey from a brood chamber, and wasn't really sure if it was vaped or not, I might consider it for my personal use.

My rationale would be that if it tasted sour I wouldn't eat it. If it didn't taste sour, it has less oxalic acid than other common foods, like spinach (1500 mg in 1 cup cooked spinach) or baked potatoes (97 mg in 1 baked potato with the skin) or almonds (122 mg in 1 ounce). Two tablespoons of honey which had 1000 mg/kg (2.5x the level where you could taste it) would have only 42 mg of oxalic acid. Check my math, but I think there are about 47 Tablespoons in a kg of honey. Since I don't eat much more than that at one sitting, I think it would be OK for me. Of course, you need to decide what is OK for yourself. At the 400 mg/kg rate, 2 tablespoons of honey would contain about 17 mg of oxalic acid, which is not much compared to a lot of other foods.

Oxalic acid is common in a lot of foods. 

A list of 122 foods containing oxalic acid, and the typical amount in each can be found at the following link:
https://www.nutritionadvance.com/high-oxalate-foods/


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## lamarcarama (May 3, 2015)

Opening myself up to flames, but after a couple years of extreme protection, I've settled into a route where I don't use any eye protection or mask when applying OAV. I have the luxury of keeping only 4 hives and an OAV rig on a digital timer. So I start a treatment and then leave for 20 minutes. I come back after 5 minutes of OAV and 15 minutes of cooling/dissipation and repeat the process for the remaining hives. Protection is a wonderful thing, but logic and common sense can also go a very long way to protecting your health both long and short term IMHO.


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## C. Scott Taylor (Dec 12, 2015)

There has, so far, been no mention of the formation of kidney stones comprised of oxalic acid and calcium.
My body produces kidney stones of this type. 
Ask a woman who has passed kidney stones and given birth which is worse. I guarantee she will say kidney stones.

The foods mentioned in the first post are dangerous for people like me.
The human body has no use for oxalic acid and it must all be excreted. Some metabolisms cannot adequately achieve that.
Mine can't.
Having had four kidney stone experiences, passing them, and having had to have a "percutaneous nephrolithotomy" (where they pierce your back with a probe into your kidney, then insert an ultrasonic device to blast the stones into sand, then insert a 'scoop' to extract the sand, then suture you closed with a drain tube for a week, I have experienced the dangers of oxalic acid.

I will never expose bees, or honey, to this stuff knowingly.
I am fortunate to be in Australia, where, so far, varroa destructor has not taken up residence.
If they do get here, I will have to find another way of coping, if I remain as a beekeeper at all.

I hope those of you who are cavalier about oxalic acid and exposure to it take heed, and avoid the excruciating agony of forming kidney stones as a result.
And please consider whether you are comfortable exposing others to it thru the honey you produce.


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## little_john (Aug 4, 2014)

C. Scott Taylor said:


> *The human body has no use for oxalic acid* and it must all be excreted.


That's quite an assertion ...

I hope you'll agree that the human body has a need for a daily intake of Vitamin (Vital-amine) C - otherwise known as ascorbic acid - and, when ascorbic acid is metabolised it produces oxalic acid. Hence oxalic acid can routinely be found within normal human metabolic pathways.

Perhaps you'd prefer people to use synthetic miticides instead of one which is a natural constituent of honey, and thus a substance that the bees have been familiar with for millions of years ? Is not the use of synthetic miticides in preference to oxalic acid an approach more deserving of the description "cavalier" ... ?

LJ


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## luelle (Aug 20, 2019)

lamarcarama said:


> Opening myself up to flames . . . . . . . . .Protection is a wonderful thing, but logic and common sense can also go a very long way to protecting your health both long and short term IMHO.


Why so? Because to me, you seem to be a person who engages brain before you open mouth (or type on this forum). I'd say that's a good thing and I don’t think you should apologize for that. I also say more power to all who apply the same powerful logic. But a person can only do this when they are informed with backed up facts. That's not the same as someone's opinion at all. I believe that JWPalmer's first idea with this post is clear: help beekeepers make better choices for themselves to keep hives alive and honey safe. Thanks to others who have added some more nuggets of scientific knowledge as well. I can't thank you enough for the references.

We could start a list of things (Think: bleach, ammonia, lawn chemicals, plant fungicides, second hand smoke) that are in most US households that have very similar potential issues; either over time or within minutes; either via ingestion, inhalation or exposure or a combination thereof. What makes or brake the users of such products is the lack of knowledge and common sense (which isn't so common). 

I was reading a NASA study about house plants that filter for chemicals in the air. It’s amazing how much crap we are all exposed to day in day out, without our knowledge, just because some organization decided it was OK because the levels are low. I’ve attached the sheet in case some of you wish to see what chemicals we accept our daily lives without a second thought. 

The logic behind the toxicity of OA by JWPalmer in honey is the same logic that applies to "lead toxicity" in lipsticks. It's absurd to talk about lead poisoning when you start looking that the facts. In the case of lipsticks, you'd have to eat something like 8 whole lipsticks to get to poisoning levels. Ridiculous right? Yet people are easily swayed by the rhetoric. 

It's all boils down to managing risk to me. 

I'm new to the fascinating world of beekeeping. I started on the band wagon that "no chemicals" was the way to go, until I got slapped back to reality with things like this post and the likes of the material from other sites such as Randy Oliver's. Using NO treatments is a bad idea. Using the wrong treatment at the wrong time and in the wrong way is also a terrible idea. I find that the dialogue about infectious apiaries is hardly discussed, thought it might be because I'm too new. 

At the end of the day, we all want to do what's best for ourselves, the people we love and for the bees, which ultimately means for the world's food supply. I sincerely believe that this is the crux of the matter. I've since stepped down from the band wagon and use common sense as much as I can muster - IPM - along with a healthy dose of conservationism. To me this means that if I need to treat - I treat. The treatment I chose will depend on the situation and I'll be asking for peoples' professional opinions before I decide. Like doctors in a hospital: you don't cure a cold with antibiotics. But if the problem gets worse, you ask for help so to bring in the big guns. 

I believe that sound practice in everything is paramount. I also think that opinions can be more damaging than not. Especially with beekeeping where our practices determine whether or not the bees can do what they do best: which is for hives to stay alive and healthy so the bees can deliver the goods we all need and love. 

I'm just along for the journey, along to help . . . whatever that means. Some times that means doing something I don't like so much. I had NOT considered OA as an option before. I do now, though it’ll probably be something I put in my “big gun” case. 

Off the soap box I go. . . Thanks for this awesome thread!


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## Robert Holcombe (Oct 10, 2019)

Lamarcarama: Some special advice when handling oxalic acid OA - wear eye protection. I use my bee jacket veil and wrap around prescription sunglasses. I have taken people to the hospital for lack of eye protection, mechanical and chemical damage when I worked in a chemical plant and lab. The most dangerous time, IMO, is when scooping OA and handling the wand cup. One misstep and it can "fly" - into an eye! I like my eyes. I also keep a 1/2 bucket of water with me and wet towel - great for cleaning up. If I wiff something I simply hold my breath. My internist told me not to eat it, OA, and if I breath vapors I will cough my guts out - period. With time and experience my nine hives are apparently well propolized - no leaks. I treat nine spaced out hives in less than 2 hours. 

Bee careful


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## elmer_fud (Apr 21, 2018)

JWPalmer said:


> Where else would you find the first aid for exposure to a product to be to liberally drench yourself with more of the same product?


:lpf:


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## lamarcarama (May 3, 2015)

Oooh. Super good advice. Thanks. I guess I'm over-focused on the 'V' part of OAV and not thinking enough about the risk a powdered acid presents all by itself...


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## C. Scott Taylor (Dec 12, 2015)

little_john said:


> That's quite an assertion ...
> 
> I hope you'll agree that the human body has a need for a daily intake of Vitamin (Vital-amine) C - otherwise known as ascorbic acid - and, when ascorbic acid is metabolised it produces oxalic acid. Hence oxalic acid can routinely be found within normal human metabolic pathways.
> 
> ...


Thanks 'little john', for putting words in my mouth. You seem to know more about what I want to say than I do.

No.
Oxalic acid has no biological or metabolic value in the human body. It must be excreted, as I said.
To say that it can be a product of metabolic processes and is sometimes found in the body is a strawman argument.
It still must be excreted, no matter how it gets there.

Be careful with the stuff. Some people experience agonising pain from it as crystals that can form in their kidneys.

As to synthetic miticide, that's your suggestion, not mine.


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## Rader Sidetrack (Nov 30, 2011)

This study seems to be relevant at this point:

Oxalate content of foods and its effect on humans


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## little_john (Aug 4, 2014)

C. Scott Taylor said:


> Thanks 'little john', for putting words in my mouth. You seem to know more about what I want to say than I do.


I wish only to correct your errors.



> No.
> *Oxalic acid has no biological or metabolic value in the human body*. It must be excreted, as I said.
> To say that it can be a product of metabolic processes and is sometimes found in the body is a strawman argument.
> It still must be excreted, no matter how it gets there.


You are very persistent about this - I can only conclude that your knowledge of biochemistry must be limited. BTW, I said "routinely" - not "sometimes".

Just one of many papers which summarise in a few words the importance of oxalic acid in the biochemistry of humans:



> *The function of oxalic acid in the human metabolism. Robertson DS, Clinical Chemistry and Laboratory Medicine, 2011 *
> 
> Biochemical reactions in cells which involve *oxalic acid* are described. It is shown that this compound is required for *the formation of uracil *and orotic acid. *The former is a component of RNA which is common to all cells in the human metabolism. *On the basis of the biochemical reactions described a possible treatment to relieve the effects of calcium oxalate renal calculi whose origin is related to the metabolic concentration of oxalic acid is proposed.


So - oxalic acid is implicated in the formation of uracil, which in turn is implicated in RNA production, and so onwards towards protein synthesis etc. Of course excess Oxalic Acid needs to be secreted, but unlike yourself I'm not claiming that it ALL does - that appears to be your agenda, presumably as a result of your medical condition. You are claiming that Oxalic Acid has zero biological or metabolic value - but you are wrong.
LJ


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## dudelt (Mar 18, 2013)

It is all very nice to point out that OA is in most of the foods we eat and that in can be a pretty harmless compound. But using it in the manner we do as a vaporized acid or in a concentrated solution with sugar in water is not naturally found in nature or in the foods we eat. The chemical can cause permanent lung damage, burn your skin and cause blindness if used incorrectly. I was reminded of the dangers this morning when I did my annual winter OAV treatment. The temperature was about 48 degrees, very humid with absolutely no wind. Due to the lack of wind, I was in a cloud of oxalic acid for about 30 minutes. I have heard over and over again that you can get away with no respirator if you just go down wind from the hives. Well, there was no going down wind this morning. Without the respirator I was wearing, I would be in a world of hurt right now.


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## AHudd (Mar 5, 2015)

Good point Dudelt.

I have eaten a lot of spinach, but I have not yet had the desire to smoke any. I'm sure I would not like it as well.

Alex


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## enjambres (Jun 30, 2013)

I don't *ALWAYS *wear my respirator to manage the risk of a routine OAV application. I wear it because very occasionally, the routine procedure is interrupted for some urgent, completely unexpected reason. In that fraction of a second I want to know I will be protected from harm so I don't even have to think about it.

I've done hundreds and hundreds of OAV cycles, and for most of them the mask was probably unneeded. But the two times when it was needed, it likely saved me from significant respiratory injury. 

Why is this such a difficult thing? Get a mask. Wear it. Don't be foolish. Kill the mites.

Nancy


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