Wood utility poles are a vital part of the electrical distribution and communications systems in the United States and Canada. Utility poles treated with wood preservatives have proven their value through over a hundred years of use in supporting electrical conductors and telecommunications cables. The use of wood preservatives has helped conserve North America's forest resources, because a typical treated utility pole may last for decades under conditions that might destroy an untreated pole in only a year or two.

In the first half of the twentieth century, creosote was the dominant preservative used for utility poles; in the last quarter, pentachlorophenol (penta) dominated.

Pentachlorophenol is a crystalline solid which is made into a liquid wood preservative solution by dissolving it in an organic solvent, typically resembling a #2 fuel oil. This solution, which normally contains 5 to 8 percent of penta on a weight basis, is usually applied to the utility pole in pressure retorts which force the preservative deep into the wood.

Due to the fact that the preservatives in treated wood are inside the wood, and that they are relatively immobile, the potential for high exposures from working around treated wood is low. However, individuals who work with treated wood, including penta treated wood utility poles, should take common-sense precautions to minimize their exposure to the wood preservatives.

Positive Risk/Benefit Analysis

In 1986, the US Environmental Protection Agency (EPA) concluded an 8-year study of the major wood preservatives under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). The purpose of this study was to evaluate the risk and benefits from the use of the wood preservatives and to cancel the registration of the wood preservatives that did not exhibit a positive risk/benefit relationship. The study concluded that the largest exposure risk was borne by workers at the preservative manufacturing and wood treatment facilities, and that the overall benefits to society from the use of these preservatives far outweighed the risks.

In order to minimize exposure to the end users of treated wood, the industry agreed to undertake a Consumer Awareness Program to disseminate information concerning the safe use and handling of treated wood. One method of providing this information was through a Consumer Information Sheet (CIS), which contains EPA-approved language concerning the safe use and handling of treated wood. In addition to the CIS, since August of 1994 the manufacturers of treated wood have been distributing Occupational Safety and Health Administration (OSHA), Material Safety Data Sheets (MSDS) for treated wood. These data sheets are available in Canada upon request.

The CIS contains the common-sense precautions for handling and using penta treated wood. The potential exposures associated with treated wood include dermal contact and inhalation exposures (typically associated with saw dust). Dermal contact exposure is minimized through the use of gloves and clothing that prevents dermal contact. The CIS recommends the use of gloves impervious to the wood preservatives; however, EPS has agreed that utility linemen may continue to use the leather gloves preferred by linemen. If leather gloves are used, they should be replaced when they become contaminated with the preservative.

Good personal hygiene practices, such as washing hands after handling treated wood and before eating or smoking, reduces dermal exposures. Inhalation exposures are minimized by using a dusk mask whenever sawing or machining treated wood. This same precaution should be used with untreated wood, because wood dust itself is a hazardous material and the permissible exposure limit (PEL) for wood dust will be exceeded before the PEL for penta, which is contained in the wood dust, is exceeded.

There have been studies of the penta exposures of utility linemen which have confirmed two things. First, the exposure of utility linemen is very low, and far below the published biological exposure index. Second, the studies confirm that good hygiene practices and the periodic replacement of leather gloves reduce the exposure levels.

The decades of use of penta treated utility poles confirm the safety and effectiveness of the preservative, but like all products that have the potential to be toxic, they should be used with caution, following established practices of handling and personal hygiene as detailed in the Consumer Information Sheet, the MSDS for treated wood, and employer safety and health programs.