Used creosote-treated wood ties were thermally treated between 250 and 350 degrees C to recover preservative and upgrade the wood to provide an improved quality biomass for thermochemical processes. With thermal treatments ranging from 250 to 300 degrees C, the amounts of creosote, mostly consisting of polycyclic aromatic hydrocarbons (PAHs), recovered were from 47 to 79% of total creosote present in the used ties. Thermal treatment at 350 degrees C recovered 97% of total PAH compounds. Larger amounts of PAHs with higher molecular weights (HMWs) and lower vapor pressures (LVP) were recovered at elevated temperatures. Temperature above 300 degrees C decomposed the wood matrix, with a mass loss ranging between 50 and 63 wt% and produced large amounts of light organics, anhydrosugars, and phenolic compounds that would contaminate the recovered creosote. Our study concluded that thermal treatment ranging between 275 and 300 degrees C would be preferred to recover preservative for recycling and improve the wood quality, i.e., high carbon content and caloric value, and low hazardous pollutants (creosote residues) for thermochemical processes such as pyrolysis or gasification. These findings suggest that the proposed approach could be a commercially viable and environmentally beneficial alternative to landfill for used railroad ties. (C) 2016 Elsevier Ltd. All rights reserved.