Is it Safe to Put Creosote Posts Near a Garden?

Overview

• Creosote is one of the most frequently used wood preservatives in the United States. It is manufactured by distilling coal tar at high temperatures. Creosote contains hundreds of different chemicals. This toxic, oily and flammable liquid ranges from amber to black in color and it may rub off on your clothes or skin if you rub up against a post or sit on a railroad tie. Coal tar creosote -- the type used to preserve wood -- contains polycyclic aromatic hydrocarbons (PAHs), cresols and phenols. Cresols may either be man-made or found in nature, while phenols are completely man-made. PAHs are produced by burning fossil fuels. These chemicals are potential carcinogens, according to the U.S. EPA.

Uses

• Commercially, 70 percent of creosote is used in the production of railroad ties, 15 to 20 percent is used to treat utility poles, and the remainder goes towards other miscellaneous uses. In fact, it doubles as an effective pesticide. Railroad ties often last 25 to 50 years on the train tracks. They often are reclaimed and sold to landscape suppliers at the end of their useful life. If you must use creosote-treated lumber in your yard, make sure that this material is not near any vegetable gardens or edible plants. Creosote has the ability to penetrate deeply into wood, remaining in railroad ties and utility poles for decades.

Health Effects

• Some plants have shown limited abilities to take up creosote. Tuber vegetables, such as potatoes, may become contaminated when the chemicals in creosote attach to the roots. The Cornell University Extension Office recommends against using any materials that contain creosote in a vegetable garden, since the compounds may be toxic to plants. The U.S. EPA recommends that creosote should not be used at all in residential settings. Agricultural settings where farm animals may ingest the toxins are off-limits, too.

Alternatives

• Fortunately, gardeners have a wide variety of safe materials to choose from when it comes to vegetable or flower gardens. Lumber such as redwood or cedar is naturally resistant to insects and decay. Metal posts, or those made from composite materials, are safer than creosote-treated lumber. Gardeners building raised beds should use untreated hardwood boards or concrete blocks instead of railroad ties.