Tenino Copper Naphthenate®

2% metallic copper by volume



Tenino Copper Naphthenate® contains 2% (as metal) Copper Naphthenate in oil. This ready-to-use solution is conveniently packaged in both pints, and gallons. Tenino Copper Naphthenate® is ready-to-use requiring no mixing or dilution. It can be applied by brush, or dip. Use it for end-cut protection on treated wood. Tenino Copper Naphthenate® conforms to AWPA Standard M-4, Section 7.1.1. requirements.
By Law: Always apply Tenino Copper Naphthenate® in a manner consistent with the label.

Tenino Copper Naphthenate® meets the requirements set forth in AWPA M4 Standard.

Tenino Copper Naphthenate®
Tenino Copper Naphthenate® is a ready-to-use General Use pesticide, always read and follow Label Directions. Tenino Copper Naphthenate®

The appropriateness of the preservation system for field treatment shall be determined by the type of preservative originally used to protect the product and the availability of a field treatment preservative. Because many preservative products are not packaged and labeled for use by the general public, a system different from the original treatment may need to be utilized for field treatment. Users shall carefully read and follow the instructions and precautions listed on the product label when using these materials Copper Naphthenate preservatives containing a minimum of 2.0% copper metal are recommended for material originally treated with copper naphthenate, pentachlorophenol, creosote, creosote solution or waterborne preservatives. Use of copper naphthenate preservatives with a minimum of 1.0% copper metal is appropriate in those regions of the country where the higher concentration material is not readily available.

AWPA M4 Standard Section 7
Tenino Copper Naphthenate® is available at many local building supply and hardware stores and online at mazon.com.





Tenino Copper Naphthenate® is Non-Corrosive to Hardware and Fasteners

In corrosion studies Tenino Copper Naphthenate® demonstrated no excessive corrosion of hardware and fasteners due to contact with the preservative.

Protects Against

Subterranean Termites

Carpenter Ants

Decay Fungi

Drywood Termites

Wood Destroying Beetles

Powder Post Beetles

Formosa Subterranean Termite Protection
Tenino Copper Naphthenate protects against insects including Formosa Subterranean Termites Lightbox

Copper is both repellent and toxic to termites. The University of Hawaii has found Copper Naphthenate in wood at loadings of 1.5 lbs. per cubic foot is resistant to Formosan Termite attack and degradation. Tenino Copper Naphthenate® will successfully protect against termites only if minimum loadings and sufficient penetration are achieved. Tenino Copper Naphthenate® is best used to supplement pressure-treated preservative wood protection in aggressive hazard class environments envisioned in AWPA Use Category 4, 4B,4C.


Copper Care Wood Preservatives, Inc. formulates Tenino Copper Naphthenate® with low VOC oils to comply with the South Coast Air Quality Management District's (SCAQMD) Rule 1113, and ICC 700 National Green Building Standard (NGBS) with less than 350 VOC grams per liter. Tenino is 100% domestically sourced from recycled copper and reclaimed by-products.

Tenino Copper Naphthenate®

with 2% copper as metal by volume, may be used to satisfy Standards and Codes to treat cuts drill holes, abrasions, and injuries to lumber

"Field-cut ends, notches and drilled holes of preservative-treated wood shall be treated in the field in accordance with AWPA M4"


2021 International Residential Code (IRC)R317.1.1

"Preservative-treated wood "Lumber, timber, plywood, piles and poles supporting permanent structures required by Section 2304.12 to be preservative treated shall conform to the requirements of the applicable AWPA U1 and M4 for the species, product, preservative and end use."


2021 International Building Code (IBC)2303.1.9

"Lumber, timber and decking used in structural applications shall be field treated in accordance with Section 6.1 when cut or drilled during construction."


2023 AWPA M4 StandardSection 6.2


Copper Naphthenate preservatives containing a minimum of 2.0% copper metal

2023 AWPA M4 Standard Section 7.1.1e

Always use Tenino Copper Naphthenate® (2% as metal) when treating cuts to satisfy AWPA Standard M4. And comply with building codes.

For more information about AWPA M4-21 Standard visit the AWPA website or purchase the 2023 AWPA Book of Standards.

For more information about the International Building Codes (IBC), and International Residential Codes (IRC) visit the International Code Council (ICC) website. The complete IBC and IRC may be purchased from the ICC's website and may be on display at your local building inspector or licensing office(s).

Tenino Copper Naphthenate used to treat a drilled hole in a new treated pole

Tenino Copper Naphthenate is easy to apply to wood surfaces

Reveals Natural Wood Grain

The bright green coloration of wood freshly treated with copper naphthenate will fade to a brown copper tone with exposure to the elements outdoors.

These freshly treated cedar roof shingles demonstrate the change in coloration from fresh application of Tenino Copper Naphthenate® after just three months.

Location Nebraska, Season summer (early June to mid-August); Results will vary based on species and moisture content of the treated wood, geographic location, season, climate, air movement, as well as the amount and intensity of exposure to sun.

Move the slider bar over-top the image left and right to manipulate the before and after.

Treated Wood Warranty Protection

Tenino Copper Naphthenate protects cut wood best.

Pressure treated wood products such as MicroPro®, LifeWood®, EcoLife™, AC2®, Wolmanized®, EraWood® and others, have warranties which exclude coverage when cuts, holes, etc. have not been field treated with a brush on end-cut solution. Each warranty's language differs (see specific products warranty for exact language), in most instances Tenino Copper Naphthenate® with 2% metallic copper satisfies warranty language requiring an end-cut solution application be field applied as a condition of warranty. If your lumberyard or building supply store doesn't carry Tenino Copper Naphthenate®, protect your investment and request Tenino Copper Naphthenate® wherever you purchase pressure treated wood or lumber with a limited warranty. 

MicroPro®, LifeWood®, EcoLife™, AC2®, Wolmanized®, EraWood® are Registered Trademarks and property of their respective owners. 

Regulatory Documents

Tenino Copper Naphthenate® is available in a convenient pint bottle with pour spout cap.