History of Copper Naphthenate As a Wood Preservative

Copper naphthenate has been used as a wood preservative since 1889. It was first used in Germany and has been in commercial use since 1911.

Copper naphthenate was used to treat the suspension bridge pictured to the left near Drift Creek Falls on a US Forest Service Trail in Oregon.

Copper naphthenate was recognized in American Wood Preservers Association standards in 1949, but did not gain wide use for pressure treatments until the late ’80s, when it began to be used for cross arms, bridges, utility poles, fence posts and lumber. Also in the ’80s, regulatory activities stimulated interest in copper naphthenate because of its general use classification.

Copper naphthenate is also used in non-pressure applications, including field-applied preservatives and coatings. Uses include wood shingles, millwork, pallets, beehives and non-wood applications such as tents, fishnets and other fabrics. Merichem Chemicals & Refinery Services LLC (MCRS) currently supplies naphthenic acids to the producers of copper naphthenate and is also active in the American Wood Preservers Association. MCRS supports and advocates the use of copper naphthenate as a preservative.

Why Copper Naphthenate Is the Best Choice 

There are many effective and widely used preservatives for wood. Most will provide the desired 40+ year service life expected for a utility pole such as the copper naphthenate treated pole to the right. However, copper naphthenate is the best choice when considering life span, worker and user safety, environmental friendliness, and regulatory treatment.

• EFFICACY: Laboratory and field tests have proven copper naphthenate to be an effective wood preservative with a life span similar to other preservatives.

• RESISTANCE TO LEACHING: Soil mobility tests demonstrate that copper naphthenate is not transported through the soil by water. Environmental and toxicological studies show that it would have little or no impact on wildlife.

• FLAMMABILITY: Flammability of copper naphthenate treated poles is similar to other oil borne preservatives. Afterglow is not a factor with copper naphthenate.

• GAFF PENETRATION: It takes less effort to gaff a copper naphthenate treated pole than an untreated pole. Because of copper naphthenate’s organic nature, treated wood does not become brittle or hard. Tests with four different gaff brands showed that it took 64% less force to gaff copper naphthenate treated Southern Pine, Douglas fir or Western Red Cedar poles than untreated poles of the same species.

• STAKE TESTS: Stake tests have demonstrated that copper naphthenate provides years of extended service life. Tests were conducted by the U.S. government and university laboratories at sites throughout the country.

Secondary Applications for Copper Naphthenate Treated Wood

When copper naphthenate treated wood is removed from service, it is commonly used for parking lot bumpers, landscape timbers and fences.

Copper naphthenate treated wood can be used in these secondary applications or be disposed of in approved landfill sites or incinerated. Always consult state or local regulations when disposing of any type of treated wood products. Copper naphthenate in liquid form should not be disposed of in an aquatic environment because of its toxicity to fish.

For more information, read our Product Bulletin.

Merichem Copper Naphthenate Wood Preservative:
An Age Old Wood Treatment for a New Age Environment

Copper naphthenate has been used as a wood preservative since the turn of the century. It is also used for remedial treatment as pictured to the right. AWPA-4 Standard M-4 provides guidelines for the use of copper naphthenate for remedial and non-pressure applications. Today’s environment requires a product that not only preserves the wood, but also ensures the product is safe, durable, effective and environmentally friendly. With over 50 years of experience in specialty chemicals, you can depend on MCRS copper naphthenate to meet your needs. Our technical sales staff and Research and Development Department will be happy to assist you in determining your needs. Click Contacts.