1 - EPA says there is no approved use for creosote in residential settings.
Q. We have just had a slope near our house terraced with old railroad ties. Is it safe to plant fruit/vegetables in the resulting raised beds?
A. This question comes up periodically. In the past I have recommended lining the railroad ties with plastic to reduce contact between the extremely slowly leaching creosote from the railroad ties and the soil. The surfaces which are accessible to you and your children should be covered with wood, or other materials, to prevent skin contact and staining (contamination) of clothing. Since the chemicals leach from the wood very slowly and are insoluble in water, there seemed to be only slight concern regarding creosote from old, aged, railroad ties. However, new information indicates that the ties should not be used in landscapes at all and vegetables should not be grown in areas near the railroad ties. Information from the Environment Protection Agency states, "There are no approved uses of creosote to treat wood for residential use. The Agency is aware that creosote-treated railroad ties are being used in the residential setting for landscape purposes and, in some instances, as a border around gardens. Such uses in residential settings are not intended uses of creosote and have not been considered in the preliminary risk assessment. If you do have creosote-treated wood in your yard, you are reminded to consult the handling precautions outlined above in this document." You can access the EPA website
EPA Website You can find additional information regarding creosote at the Centers for Disease Control web site (some interesting things about medications made from creosote bush also) at Center for Disease Control Website This information does not address old railroad ties, but does discuss long-term exposure (mainly from the manufacturing process or soils contaminated by manufacturing). The railroad ties should not result in the level of contamination discussed in this article, but you may find the information useful.
Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: email@example.com, office: 505-865-7340, ext. 113.
For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.
Please copy your County Extension Agent and indicate your county of residence when you submit your question!