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CHEMONITE®/ACZA: Chemonite® is the registered trade name for wood protected by ACZA, (Ammoniacal Copper Zinc Arsenate) preservative. It is the only AWPA accepted waterborne preservative capable of meeting penetration standards for Coastal Douglas fir at every exposure level and for all applications (from 0.25 to 2.50 pounds per cubic foot of wood by assay).

Chemonite has been safely and successfully used since the 1940’s to treat coastal Douglas-fir and other refractory species. Chemonite wood offers all the appealing characteristics of wood along with prolonged service life and protection against the major causes of wood degradation: fungal decay, termites and marine organisms. Additionally, studies indicate resistance to carpenter ants, woodpecker damage and fire.

For use in general construction, both public and private sectors, ACZA is accepted and specified to protect wood in commercial & industrial applications. Chemonite® pressure-treated wood meets the International Building Code (IBC) and American Wood Protection Association (AWPA) Standards.

The AWPA Use Category System provides the proper guidance for end-use applications (i.e. above ground exposure, ground contact & structural; from fresh water to salt water immersion).

Chemonite treated wood falls under the US EPA minimum protective precautions. Like untreated wood, when handling treated wood, gloves should be worn to avoid splinters. Dust masks and goggles should be worn when sawing or drilling. Hands should be washed before eating or smoking. Read the full text of the Consumer Safety Information Sheet also found at

Not all treated wood provides equal performance. Wood must adhere to AWPA standards and have an American Lumber Standards Committee (ALSC) approved inspection agency certify the treating process for penetration and retention of preservative.

Each piece must have an end-tag or stamp specifying the AWPA standard, retention and treatment. Look for the CheckMark™ next to the inspection agency’s logo.


When Chemonite treated wood must be cut or drilled, the exposed cut end or hole must be painted with two coats of a general use preservative to protect any untreated wood. A Copper Naphthenate solution containing a minimum of 1% copper (as copper metal) is required per AWPA Standard M4.

Chemonite wood is slightly more difficult to ignite than untreated lumber. Tests conducted at Underwriters Laboratories Inc. confirm the fire resistant qualities of Chemonite wood.

  • Douglas fir lumber treated with 0.35 pcf of ACZA had a 41.7 flame spread rating, which is a Class B rating.
  • Douglas fir lumber treated with 1.86 pcf of ACZA had a 24.8 flame spread rating, which is a Class A rating.
UL fire-panel testing on ACZA-treated Douglas fir and Redwood, January 1977
 Summary Table

2003 & 2006 International Residential Code – Fasteners – Section R319.3

“Fasteners for pressure-preservative and fire-retardant-treated wood shall be of hot-dipped galvanized steel, stainless steel, silicon bronze or copper. Exception: One-half inch (12.7mm) diameter or greater steel bolts.”

2003 & 2006 International Building Code – Fasteners – Section 2304.9.5

“Fasteners for pressure-preservative treated wood shall be of hot-dipped galvanized steel, stainless steel, silicon bronze or copper. Coating weights for zinc-coated fasteners shall be in accordance with ASTM A-153.”

Douglas fir pressure treated with ACZA is frequently used for industrial and commercial applications such as bulkheads, wing walls, wharfs, docks, piers, marinas, bridges and decking for its long-life.
It is extremely effective against the major marine organisms that attack wood — three species of Limnoria, Teredo, Bankia and Pholads.
Specify BMP Production

Best Management Practices (BMPs) Quality Assurance Program, published by the Western Wood Preservers Institute (WWPI), provides specific parameters for pressure-treating wood products for use in sensitive aquatic environments in the Western United States and Canada. Its goal is to minimize the amount of preservative placed in the wood while assuring conformance with the established treating standards of the AWPA.

Environmental Responsibility and Safety

Chemonite treated wood has been safely and successfully used since 1940 in commercial and industrial applications. When handling Chemonite treated wood or untreated wood, gloves should be worn to avoid splinters. Dust masks and goggles should be worn when sawing or drilling. Hands should be washed before eating or smoking.

In all sensitive aquatic environments BMPs should be specified and certified to assure that treated wood products are manufactured in a manner that minimizes any potential for adverse impacts.

Dispose of cut ends in a sanitary landfill. Treated wood should not be burned in open fires or in stoves, fire-places or residential boilers.


Field Handling Recommendations

Construction: Borers, termites and decay can attack treated wood when the treated outer layer is removed or damaged. All structures should be prefabricated before treatment. Minimize problems by specifying framing and boring before treatment whenever possible. All untreated wood exposed by cutting, drilling or damage should be adequately field treated with copper naphthenate solution.

Fasteners: Around water, avoid corrosion by specifying all timber products be properly air seasoned or kiln dried prior to installation.

Always use post hot-dipped galvanized or stainless steel hardware.