We commonly see utility poles in our everyday lives. They hold up the wires that bring electricity to our homes, and support the growing network of phones, computers, and televisions. Although wires in new developments are underground, there are still about 120 million utility poles being used in the U.S.

Poles are often treated in order to preserve them. Some threats to the pole’s structural integrity include rot, insects, fire, and fungi. The most common preservatives used in the country are creosote and CCA. Creosote is made from coal-tar, and has been used in the U.S for over a century. Another type of preservative, is made from oxidized salts of copper, arsenic, and chromium. The latter two are toxic to wood-eating insects, and chromium is used to bind the preservative to the wood.

Once the utility pole is shaped, and the preservatives have been created, the two products are combined in a process called pressure treating. The wood pole gets soaked in a preservative, then put inside in a pressure chamber that forces the preservative into the wood.

After the pole is soaked, pressurized, and dried, it’s ready to be taken to the utility provider. The most common way to transport poles is trucking. They leave the processing plant either or a flatbed truck or a self-unloading truck that has an attached crane. Occasionally, if the distance between the plant and the destination is a long one, a train might be used in transport.

The poles go from the plant to the utility company that has purchased them. From there, the poles go to do their “jobs.” Once in the field, workers use cranes or line beds to haul the poles into their respective holes.

When properly maintained, the average life of a wooden utility pole is 30 to 40 years. As the poles age, the original preservative it was treated with will wear away. Therefore, they must be reapplied. Most wooden utility poles in service today have received, or will receive, these chemical reapplications.

Next time you see a group of well-maintained treated utility poles, you’ll know just what it took to get them looking and working so well.