Preservative transition moving ahead

By Huck DeVenzio Arch Wood Protection

fN February, the Environmental lProtection Agency announced the start of an orderly transition in pressure treated wood.

In April, this publication printed the initial plans of various treating companies.

Now it's November. The transition has progressed six months closer to its conclusion. Change is more obvious in some geographical areas and certain applications than in others, but it is coming everywhere. More treaters are producing the new products, and lumber dealers face product and timing decisions.

Around the world, there has been growing demand for alternatives to CCA (chromated copper arsenate) preservative, the type used in traditional treated lumber. It seems to be an unstoppable trend. Despite numerous scientific studies, decades of safe use, and concerted effort by wood preserving companies, expanding segments of the public have questioned the suitability of CCA. Their concerns have been exacerbated by implications in media reports and political speechmaking.

In the United States, playground equipment manufacturers were the first group to move away from CCA. Before any regulations were imposed, companies such as Kompan and PlayNation chose to avoid unproductive debates by specifying "new generation" treatments.

Parks departments, outdoor furniture companies, and commercial specifiers also began choosing alternative products more frequently.

In light of the inevitable movement, CCA manufacturers took action to allow for an orderly transition over a reasonable time period.

The lllithdrawal Declsion

Since wood preservatives are pesticides and must be registered with EPA, the wording on their labels must be reviewed and accepted by EPA.

(This refers to labels on the preservative chemical, not end tags on treated lumber.) The three major CCA producers voluntarily agreed to modify the wording on CCA labels. EPA announced their decision: after December 30. 2003. CCA is not to be used to treat wood for playgrounds, decks, and typical residential applications.

The Agency said, "EPA has not concluded that CCA-treated wood poses unreasonable risks to the public for existing CCA-treated wood being used around or near their homes or from wood that remains available in stores."

EPA added that CCA will continue to be used to preserve wood for industrial, utility, and marine uses.

Before the label re-wording is approved, EPA made it available for public comment. More than 6,200 comments were received. Some requested a continuation of CCA in certain uses (e.g., agricultural fence posts), while others argued for further restrictions.

EPA is evaluating the comments and will make recommendations to the CCA producers prior to granting label approval.

New Generation Cholces

The transition is well along in some geographical areas. In Seattle, Portland, San Francisco, and Chicago, retailers such as Dunn Lumber, Parr Lumber, Truitt & White, and Hines Lumber pioneered the introduction of the new products, which are now readily available.

In other areas, stocking dealers remain scattered, but many outlets will place special orders with producers.

Treating companies across North

America have converted production to handle the growing requests for new generation products.

The alternatives are being called "new generation," "next generation," or copper-based preservatives. Two chemicals predominate: copper azole and alkaline copper quaternary. Copper azole (listed by the American Wood-Preservers' Association in CBA and CA-B formulations) is used to produce Wolmanized Natural Select wood. Alkaline copper quaternary (also available in multiple formulations, all abbreviated ACQ) is impregnated into wood sold under various brands, including ACQ Preserve and NatureWood.

When treated to AWPA standards, the new generation preservatives provide longevity equivalent to CCA. Both copper azole and alkaline copper quaternary rely on copper as the primary active ingredient with an organic fungicide (azole or quaternary) to protect against copper-tolerant fungi.

The production, performance and appearance of the new treated woods are similar to that of CCA-treated materials. Common sense handling practices. such as not burning scraps. still apply. Recommended retention levels are not necessarily the same as for CCA-treated wood or for each other; dealers and builders should note the intended use (i.e., Above Ground, Ground Contact, etc.) indicated on the end tass.

Part-new,parttraditional bills of materials are likely to become more common.

There is a cost difference: the prices of the new products are somewhat higher than CCA treatment.

Incidentally, the new types are not really new, both having been used commercially for more than a decade after years of testing.

Mixed-Treatment Project Represents The Future

A recently constructed boardwalk in Seminole, Fl., is indicative of upcoming mixed-treatment projects.

The elevated walkway stretches for nearly three-quarters of a mile over a brackish Gulf Coast marsh in Boca

Ciega Millennium Park. Decking, railing, and curbs are Natural Select wood (treated with copper azole preservative), while the round poles, beams and joists that support the walkway are CCA treated.

Such part-new, part-traditional bills of materials are likely to become more common. Until now, CCA was a convenient, all-purpose treatment. Now, however, specifier preferences and the label mandate will dictate the use of new generation products for some components, with CCA being used for others.

In this case, brackish water made CCA poles a necessity-the new-generation products are not approved for saltwater applications. In other projects, where CCA components are permitted, economics may favor CCA-treated wood.

The history of wood preservation has been a stream of process improvements and preservative developments. The evolution is sure to continue. What is "new generation" now will, in a few years, become the traditional treatment as even newer preservatives-probably al l-organ ic-are introduced.

Preservative manufacturers intend to create advanced chemicals that treating companies can employ efficiently to supply to adaptable dealers who serve the changing preferences of the marketplace. This will not be the last transition in treated wood.