Our contractor treated the edge of some plywood and the bottom of some studs with copper naphthenate. The goal was to treat yummy wood at the concrete interface, which is a good thing since termites love our house.

But the smell!

I can't stand it, especially in the small one stall bathroom. Various other people who have walked into the space have noticed and commented on the smell... and right now the area is perpetually open and has been for weeks.

And I know the smell lasts forever. Yet here the wood in question will mostly be covered by drywall. Is there anything can I do to mitigate the copper green smell? Has anyone else been successful in containing such a smell?

The product was: Cuprolignum Standard Green No. 300, by Rudd Paint & Varnish Company

  • Copper naphthenate 34.5%
  • Chloroorthophenylphenol 2.5%
  • Petroleum Solvent 63%

Slogan "Where there is Cuprolignum there is no rot"

4 Answers 4


This product is for exterior use only - per the EPA and is illegal to apply inside or under your home. The only way to mitigate the odor is to allow it to dry - Copper Green was sprayed under my subfloor in the crawl space of my home. Which is literally on the label - per the EPA RED document label review - For Exterior Use Only - do not apply in crawl spaces or spray -


EPA Copper Napthenate toxicity

Link to recent EPA review on copper napthenate salts - which is now illegal to manufacture a sell in the US - as well as Canada and the UK.


EPA Review Documents 2024 - finding the chemicals toxic


Also look up the SDS or MSDS sheet which includes toxicity, side effects, and more - legally has to be available on the products website and produced to you by your contractor. If applied by a pest control company they are also in violation and can be fined if applied in or around your home. Contact your local agriculture commission and file a complaint - take photos, video, and keep records of witnesses, and the duration of the odor. If the residue is exposed do not touch! Especially if you have children, highly toxic and can cause dermal and inhalation health issues. ITs a neurotoxin, causing vomtting, fainting, diareaha, dermatitis, inflammation of the skin, and worse -

Lebel instructions state paint on exposed wood, allow to completely dry before installing - referencing fences. This product should never have been applied to any wood inside your home and there is nothing. you can do about the odor, sealing the product is a good start if you can reach the wood, with Kilz oil based primer, but the wood in its entirety has to be sealed, as a petroleum based product is absorbs a seeps further up into the wood.


I ended up using metal HVAC tape. It worked very well. I also tried spray plastic on some areas unsuitable for the tape and it worked. The airtight seals keep in the copper smell, and the room instantly became more livable.


A thick four coats of floor paint that is meant to be impermeable to damp and impervious to floor traffic helped seal in this stuff where someone used it to treat a bathroom stall against rot.

Yes, the stuff just smells horrible. It's essentially copper contaminated moth balls with a little extra phenol for sniffy goodness and not for interior use at all.


I used 1 coat of Bulls Eye 123 primer then 2 coats of AFM Hard Seal (buy online) to mask the horrible/ toxic odor.

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