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EPA Officially Bans Utility Pole Preservative ‘Penta’

March 17, 2022
For the next two years, registrants may continue to produce, sell and distribute wood preservatives containing pentachlorophenol while wood treatment facilities transition to alternatives.
The U.S. EPA has canceled the registration for pentachlorophenol, or “Penta,” a wood preservative utilized primarily on utility poles that has been in use for decades.

During the registration review process, EPA found that given the emergence of viable alternatives, “the risks pentachlorophenol poses to workers’ health outweigh the benefits of its use.”

The EPA said the complete phase-out of pentachlorophenol will be conducted over 5 years and is intended to “ensure stability within the utility pole industry by giving wood treaters time to switch to alternative wood preservatives.”

For the next 2 years, registrants may continue to produce, sell and distribute wood preservatives containing pentachlorophenol while wood treatment facilities transition to alternatives. After 2 years, pentachlorophenol will no longer be manufactured, sold or distributed in the U.S.

After February 2024, wood treatment facilities will be allowed to use their existing stocks of pentachlorophenol to produce treated wood for an additional 3 years.

The decision – which followed a 60-day comment period -- concludes EPA’s registration review of pentachlorophenol.

The EPA says its decision aligns the U.S. with the United Nations’ Stockholm Convention on Persistent Organic Pollutants Annex A listing of pentachlorophenol, which generally requires parties to the Convention to eliminate its production, use, import, and export.  But the U.S. has traditionally resisted aligning with the Stockholm Convention agreement.

Alternatives to pentachlorophenol that the EPA listed include copper naphthenate and DCOIT, along with wood preservatives such as chromated arsenicals and creosote.

To read EPA’s final decision, see docket EPA-HQ-OPP-2014-0653 at

Read the Final Decision.

Last year the EPA proposed canceling the registration for penta and established a 60-day comment period, which generated many responses for and against the potential ban. Here are some statements shared by associations and manufacturers who supported penta production and use last year prior to the final ban decision by the EPA.

Wood Preservation of Canada: “For over half a century, penta has been the most commonly used industrial oil-borne preservative for utility poles in North America. The proposed 5-year phaseout for products containing penta in the U.S. will have impacts on the industrial infrastructure across the border.”

North American Wood Pole Council: “Utility companies have relied on penta for more than 85 years and continue to select it as the preservative of choice. Penta is the most specified oil-based preservative for the two most-used species for utility poles, Douglas fir and Southern pine. There is no question the removal of penta … will disrupt the market for utility poles. The unintended disruption can decrease demand for penta-treated poles, which will hinder the ability to sell existing penta-treated stock. Waste disposal options for the solid penta blocks will be even more challenging.”

Stella-Jones Corp.: “Today there are a lack of viable alternatives to penta for treating poles and this lack of alternates would cause significant disruption to national production of critical infrastructure building material. The utility industry needs the flexibility to respond to demands for supply of wood poles.”

The Oeser Co.: “We would think that EPA would be responsibly looking at a way to encourage a domestic chemical manufacturer to enter into the marketplace with penta. In fact, by proposing a phaseout of penta, EPA is creating the opposite effect. We believe that a phaseout by EPA is short sighted. Penta is a proven, reliable wood preservative. Keeping the door open for the ongoing manufacture and use of Penta, creates, at the least, the opportunity for a manufacturer to evaluate the viability of producing this useful chemical.”        

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