The Extended Release Oxalic Acid Treatment (OAE) is approved by the EPA on a limited basis. Please read here for more information. 

EPA and Approved Treatments

Please decide for yourself how and when you will use OAE. Based on the following, it seems the EPA has removed concerns about OAE use with honey supers.

As per above, the EPA recently established an exemption from the requirement of a tolerance for residues of oxalic acid on honey and honeycomb:

“This regulation eliminates the need to establish a maximum permissible level on these commodities for residues of oxalic acid. Consequently, it is now authorized to use Api-bioxal year-round, including when honey supers are in place.”


Randy Oliver is arguably the expert on Extended Oxalic Acid (OAE) treatment. Randy is a world-renowned speaker, educator, bee biologist, leading researcher, commercial beekeeper, and regular contributor to the American Beekeeping Journal. He is one of the premier beekeeping speakers in the U.S. and the owner/author of http://scientificbeekeeping.com.


“Beekeepers worldwide are caught between a mite that has proven able to rapidly develop resistance to synthetic miticides, and the slow pace of development and adoption of mite-resistant bee stock – the eventual solution to varroa.  During the interim, by choice or lack of alternatives, beekeepers are shifting to the use of “natural” treatments.  Oxalic acid (OA) is one of the most promising of those treatments, but its efficacy is limited unless applied during a broodless period. An extended-application method would free it from that limitation. The problem with oxalic acid is that either of the currently approved application methods (dribble or vaporization) kills mites for only about three days.  So unless applied during a broodless period, or repeated at 4-day intervals, oxalic is not very effective over much of the season, due to a proportion of the mites being protected in the sealed brood.  By creating an extended-release formulation, we may have found a treatment that is “natural,” suitable for organic approval, safe for the applicator, non-contaminating of honey, shows no noticeable adverse effects upon the colony, as well as being inexpensive and highly effective at reducing mite populations.” We will refer Extended-Release Oxalic Acid treatment as OAE.


Here are some links to his work and recommendations:

We will be following his latest recommendations here.


OAE is a very inexpensive treatment, but you need some gear to safely and accurately make it. Here’s what has worked well for me:


Induction Cooktop

Provides a safe, no-flame way to heat up the solution. The cooktop surface does not get hot during use, as the heat is induced directly into the pan. One less thing to worry about.



Digital Kitchen Scale

To weigh the Oxalic Acid and Glycerin.



1/3 Size Pan 6″ Depth

Double boiler to safely heat and mix the OA solution.



1/3 Size Pan 4″ Depth

Double boiler to safely heat and mix the OA solution.



Kitchen Tongs

Mixing the solution and bathing the pads.



Do not let OA solution splash into your eyes. It is a guaranteed trip to the ER. I highly recommend wearing a face shield. I find them more comfortable than goggles, and they protect more of your face. If you do use goggles, make sure they fit tightly against your skin. Please do not use safety glasses – get tight fitting goggles or a face shield. Wear disposable rubber gloves.

Face Shield

Protect your eyes and face!




SpillTech Universal Maximizer Pads 15″ x 19″

This is a large quantity of Randy Oliver’s preferred pad material. GBA may make a purchase of these, so you may be able to get a smaller quantity through the club. A good alternative are Swedish Dishcloths, available from Walmart.


$80 for a pack of 100. This is enough to make 800 pads. 

$0.10 per dose

Oxalic Acid

The key ingredient. Handle with care – OA is toxic and very acidic. Always wear gloves, eye protection, and a mask.


$16 / 2 lbs. Two pounds will produce 18 doses.

$0.89 per dose

Vegetable Glycerin

Used to dissolve the OA and adhere to the pads. Best measured by weight. 


$25 / 1 gallon. Smaller quantities are available. This is enough for 80-90 doses.

$0.31 per dose

Startup Costs

Equipment: $148
Supplies: $121
Cost per dose: $1.29



Per hive:

  • 1/4 of a SpillTech Maximizer Pad, or 1 Swedish Dishcloth. Cut these in half, and use 2 pads (half doses) per hive.
  • 50 grams glycerin
  • 50 grams Oxalic Acid
The dose per hive is two 25g pads, for a total dose of 50g of Oxalic Acid. 


  • Always keep a jug of baking soda solution at hand to neutralize any spills or splashes! (10 heaping tablespoons of baking soda per gallon of water).
  • Best do this in a sheltered outdoor area with no wind, or in your garage. Oxalic Acid is toxic… I strongly recommend not doing this in the kitchen or indoors. If you are outside, be careful about the OA blowing around. It is a similar consistency to granulated sugar, so a gust of wind would tend to blow it around, making for a hazardous workspace and more involved cleanup.
  • Oxalic Acid is poisonous and corrosive. Do not get this in your eyes! Wear eye protection! Be very careful about splashes – apply some of the baking soda immediately to any splashes. 


  1. If using the Maximizer Pads, cut them in 1/8’s. For Swedish Dishcloths, cut them in half. You want a pad approx. 3-4″ x 7″.
  2. Prep your storage container – I use a heavy-duty Ziploc bag, and roll back the top so it stays open for easier insertion of the wet pads.
  3. Put on your eye protection, rubber gloves, and mask.
  4. Put about an inch of water in the deeper pan, and bring it to a boil.
  5. Put the shallower pan on the digital scale, set it grams, and zero (tare) it.
  6. Slowly pour in the glycerin to the computed weight (50g x number of treatments).
  7. Re-zero the scale.
  8. Carefully add the Oxalic Acid to the computed weight (50g x number of treatments).
  9. Put the shallow pan in the boiling deep pan. Use the tongs or a spoon to stir the mixture. Stir until the mixture is clear, and all the OA is dissolved. The OA is frequently lumpy… take your time and get all the lumps dissolved, stirring slowly and gently.
  10. Turn off the stove.
  11. Insert the pad material halves, and use the tongs to gently move them around until all of the OA mixture has been absorbed.
  12. Place the OA pads into your storage container, seal, and rinse off the outside and your gloves to remove any residual OA. 
  13. Thoroughly rinse and clean all your equipment outside. If in doubt, pour some of the baking soda solution on it.


Place two pads (2 x 25g of OA) on the top bars of the lower brood chamber. 

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