What's in brown pressure-treated wood?

[David Nebenzahl]

Just bought some PT lumber today. Both Home Despot and the local lumberyard had the same stuff: dark brown. Looks kinda nice, actually, kinda like it's pre-stained. (Didn't buy at Home Despot 'cause all they had were 20' lengths in most sizes, whereas my only-slightly-higher-priced local yard had 8s, 10s, 12s, ... FAIL!)

Does anyone know what the chemical agent is in this new brown stuff? I assume it's less toxic than the bad old copper arsenate.

Like they say, it looks like brown is the new green.

[Tegger]

David Nebenzahl wrote in news:4c1815f9$0$2394$ [e-mail]:

That "bad old copper arsenate" was effective, cheap, and far less toxic than the current scare stories would have you believe.

Some info in this PDF, from the USDA:

Your brown wood is probably the same sort of brown coloring they use to decorate mulch, overlaid on regular green non-copper PT.

[Larry W]

Request an MSDS from HD or the product manufacturer. It very likley may be available on line as well.

[David Nebenzahl]

On 6/15/2010 5:14 PM David Nebenzahl spake thus:

Well, I did find out about the wood I bought, no thanks to anyone who replied to this thread so far, except for Tegger, who despite their dismissive attitude towards toxics did provide a link to a document that actually had at least some of the information I was looking for.

The label on the lumber identified it as "Alkaline Copper Quarternary Type D". The USDA document

has this to say about it:

Alkaline copper quat (ACQ) is one of several recently developed wood preservatives. It contains copper and a quaternary ammonium compound. ACQ protects against decay fungi and insects but has not been standardized for use in marine applications. Multiple variations of ACQ have been or are in the process of being standardized.

ACQ-B is an ammoniacal copper quat formulation; ACQ-D is an amine copper quat formulation; and ACQ-C is formulated with either ammonia or amine and a slightly different quat compound. Currently ACQ-D is the most commonly used formulation. Like ACZA, ACQ-B is able to penetrate Douglas-fir and other difficult-to-treat wood species and is used primarily on the West Coast. Wood treated with ACQ-B has a dark greenish-brown color. ACQ-D is manufactured with amine copper, which gives the treated wood a light brown color. ACQ-D is not as effective as ACQ-B in penetrating difficult-to-treat woods. Both ACQ-B- and ACQ-D-treated wood can be painted or stained.

Still says nothing about the toxicity of the wood. My customer asked me if it would be OK to burn the wood scraps; I told him it probably wasn't such a great idea.

I guess the next step is to find the MSDS.