We’ve all heard the mantra “reduce, reuse, recycle”: the Three Rs of responsible environmental stewardship.
They are listed in this order for a reason: the most efficient way to approach sustainability and limit negative impacts on the environment is—firstly—to reduce harmful industrial processes from the outset. If it is necessary to manufacture a product, then the second R, reuse, reminds us to use it for as long as possible to, again, avoid unnecessary industrial processes. Finally, when that product’s life cycle comes to an end, recycle challenges us to transform it into another useful form, ideally a natural substance (such as burning as a fuel), with another option being to re-structure it into another product to give the material another lifecycle and delay its arrival at a landfill.
Creosote wood preservatives, along with the industrial and transportation companies that make use of them, achieves all three of the Rs of environmental stewardship, for not one but two limited natural resources: coal and wood.
Since creosote-treated wood infrastructure has life-cycles nearly equivalent to human lifetimes, significantly fewer trees need to be cut and processed not only for new infrastructure, but for ongoing maintenance, than if other treatments or made-made products are used.
Creosote: Ancient Organic Materials Unlocked by Modern Manufacturing Processes
As a byproduct of existing manufacturing processes, creosote reduces by requiring a minimal level of additional manufacturing for it to be produced. Coal-burning, coke production, and steel manufacturing, which have been endemic to the modern economy since before the American Industrial Revolution, literally coat industrial ovens with coal-tars. At high heats, the non-carbon content of coal distills out of coal, producing a rich, tar-like substance. These “leftovers,” which separate from the carbon content of coal under high heat, are far from trash. Rather, coal-tar creosote is a fortuitous side-benefit of manufacturing processes and has represented a form of reuse for coal since the 1800s, when it started being applied to wooden infrastructure.
Not all of the coal-tar distillate is used to preserve wood, but coal-tar distillate “creosote,” as defined by the American Wood Protection Association (AWPA) Standards, adopted this Greek-based moniker for “flesh preserver” in 1835 because it is literally comprised of primordial organic plant-matter which has protective properties. As a hyper-concentrated pitch of the Earth’s primeval flora—the planet’s first ferns and trees, compressed underground since the Carboniferous Period—creosote’s compounds endured for millions of years. Therefore, through the pressure-treatment process, creosote lends its imperviousness to the elements to wood.
Creosote wood preservatives, along with the industrial and transportation companies that make use of them, achieves all three of the Rs of environmental stewardship, for not one but two limited natural resources: coal and wood.
Making use of the coal-tar distillate creosote, naturally unlocked during coal, coke and steel manufacturing, for the preservation of wood is one of the major economic successes of the Second Industrial Revolution. However, the creative application of this byproduct has received little recognition for being a major sustainability achievement of that era. This compressed organic material has capabilities beyond what can be manufactured whole-cloth by humans. It is no wonder, then, that energy input and related emissions associated with creosote-treating wood is between one quarter and one tenth of that associated with manufacturing comparable plastic, steel, or concrete materials.
In addition to creating wooden infrastructure capable of carrying rail cars across the world’s continents, the manufacture of creosote wood preservative helped increase the sustainability of coal, a valuable and limited natural resource, by facilitating its reuse and recycling. Harvesting the coal-tar byproducts in industrial ovens essentially reuses parts of laboriously-mined coal by transforming it into other products. Creosote goes one step further by also extending the life cycle of products made from wood, another valuable and limited natural resource. Creosote treatment, by augmenting the capabilities of wood, also reduces the demand for forest resources.
Since creosote-treated wood infrastructure has life-cycles nearly equivalent to human lifetimes—decades longer than other materials or treatment alternatives—significantly fewer trees need to be cut and processed not only for new infrastructure, but for ongoing maintenance, than if other treatments or made-made products are used. (1) Older creosote-treated wood can also be decommissioned and reused in other formats with lower performance requirements, yet extending their life cycle. For instance, aging railroad ties can be moved to lower-tonnage tracks or short-line railroads, where they maintain enough strength and durability to continue to be used.
In addition to creating wooden infrastructure capable of carrying rail cars across the world’s continents, the manufacture of creosote wood preservative helped increase the sustainability of coal, a valuable and limited natural resource, by facilitating its reuse and recycling.
Improving the Environmental & Economic Sustainability of Wooden Infrastructure
These sustainability achievements also result in economic efficiencies. The long chain of reuse which creosote facilitates leads to less environmental damage as well as lower costs. According to research by the Railroad Tie Association (RTA):
- A mile of new track using concrete crossties costs approximately 30% more than a mile of new track using creosote-treated wood ties.
- Creosote-treated wood crossties are approximately 57% – 86% the cost of alternate materials in dry and moderate climates.
- Using creosote-treated crossties to replace aging ties saves U.S. railways approximately $615 million across all environments and $76 million in aquatic environments, per year. (2)
Coal-tar creosote is therefore a doubly sustainable substance. By reusing and recycling coal, and also extending the lifecycle of wood, coal-tar creosote increases the sustainability of two limited natural resources simultaneously. When creosote-treated wood finally reaches the end of its lifecycle, unlike man-made substances such as concrete or steel, it can actually be burned for fuel. In this way, coal-tar creosote comes full circle: it returns to the industrial boilers which first—accidentally—extracted it from coal. The very same creosote which has extended the usefulness of coal and wood will, decades later, also provide energy and reduce the use of other sources like fossil fuels, not to mention its own need for landfill space.
Finally, unlike man-made substances, creosote-treated wood will eventually biodegrade—following EPA guidelines for proper handling and recycling—because both wood and creosote are organic substances. Together, they can return as biomass to the Earth, from whence they both came.
Note: This article originally appeared in the March/April 2025 issue of the Railway Tie Association’s Crossties magazine.
End Notes
1. The U.S. Navy says creosote-treated pilings last 20-40 years. The U.S. Class 1 Railroads find a typical service life of approximately 40 years; the piling industry estimates that marine pilings will last about 75 years in northern areas and 40 years in southern areas of the U.S.; the U.S. Forest Service estimates that treated timber bridges last 50 years or longer, and treated wood utility poles have been shown to provide useful lives of 75 years and longer (Smith, 2007, https://creosotecouncil.org/cost-benefit-analysis)
2. Smith, Steve. “A Cost-Benefit Analysis of Creosote-Treated Wood vs. Non-Treated Wood Materials.” Creosote Council, 2007. https://creosotecouncil.org/cost-benefit-analysis.