Pressure-Treated Pine
For decades, pressure-treated pine has been one of the most popular lumber options for a wide variety of residential uses. It has been marketed as a durable and environmentally friendly fencing option that offers the qualities of top-shelf cedar at a fraction of the price.
However, these claims could not be further from the truth. Pressure-treated pine comes with a number of hidden costs and disadvantages which make it low-grade fencing option. Regardless of the treatment options employed, pine remains inferior in virtually every way to Western Red Cedar.
Production
Unlike Western Red Cedar, which is cut and shipped, pressure-treated pine goes through a complicated treatment process during which the wood is sealed into a vacuum tank, then coated in a solution containing chromium, copper, and arsenic in order to protect the wood from potential contaminants. The vacuum in the tank causes the chemicals to be absorbed deeply into the wood.
The production of Western Red Cedar involves no net production of carbon, and is considered one of the most environmentally friendly construction materials on the market. Pressure-treated pine, on the other hand, is factory-produced and undergoes a complicated treatment process. Factory production methods inherently produce additional carbon, which can have negative effects on the environment.
Chemicals
The most common form of pressure-treated pine is treated with a combination of chemicals that act as preservatives, protecting the wood from rot and decay. The three main chemicals used to treat the pine are:
- Chromium. A bactericide, chromium is not particularly dangerous to humans unless it is inhaled.
- Copper. While it is not poisonous to mammals, copper can kill fungi.
- Arsenic. Arsenic is an extremely dangerous poison that has been known to accumulate in the ground. Inorganic arsenic is used in the treatment of pine, and is less dangerous to humans.
The producers of so-called “CCA” treated pine claimed for years that the chemicals would not be harmful to humans. However, in late 2003, the Environmental Protection Agency (EPA) banned the residential use of cremated copper arsenate treated pine. The EPA believed that the chemicals posed a seepage risk which could potentially contaminate plants and people.
Seepage
The EPA ban of CCA treated pine rests on the concern that the potentially poisonous chemicals used to treat the pine could be seeping into the ground and causing residue to build in the soil.
Treated pine producers switched to two different treatment processes to replace the now-illegal CCA process. ACQ pine is treated with alkaline copper quat, while CA-B uses copper azole as a preservative. Pressure-treated pine manufacturers say that these new wood treatments do not pose a seeping danger, but other experts disagree. Some states do not allow pressure-treated woods to be used by organic food producers because of seepage concerns, raising concerns about whether or not it should be used in residential gardens.
Some gardening experts warn that treated pine used in gardens can cause the chemicals to seep into the soil, affecting any plants or vegetables that grow there. Wood containing copper in the treatment should not be used near ponds, lakes, or streams, as copper is poisonous to marine life.
Warping and Stability Issues
In addition to its other failings, pressure-treated pine is not a stable building material. Weak and prone to warping over time, pine is known to develop cracks that can damage its structural integrity. Even when elaborately treated, pine lacks the natural durability of quality Western Red Cedar.
