Question from Dalia
My neighbor wants to seal our fence saying that arsenic can leach from treated wood chemicals .Is this a problem ? And the chemicals from the sealing the wood?
Thank you so much
I love your site.
dalia
Debra’s Answer
Actually, your fence may not have any arsenic in the preservative. How old is it?
Wood used to be preserved with Chromated Copper Arsenate (CCA), which contained arsenic. As of December 31, 2003, wood with this preservative was no longer allowed by the EPA for residential applications, and is no longer sold (However, see entry 10/24/08 at Q&A: Safety of ACQ Pressure-Treated Wood). Today, wood is generally treated with Alkaline Copper Quaternary (ACQ), which is considered much safer (but not entirely safe — see Safe Handling Information at http://www.ufpi.com/literature/acqsafe-59.pdf)
ACQ IS safer than CCA, however, there is such a thing as copper toxicity. If you have high copper in your body, it can cause a wide variety of problems. So keep in mind that this is a source of copper, and you should minimize your exposure to it for that reason.
US Forest Service: Forest Products Laboratory has some good background material on wood preservatives.
If your neighbor wants to seal the fence, they should use at least a water-based sealant, and preferably one that contains few or no VOCs.
