The combustion of petroleum coke with limestone in a circulating fluidized bed (CFB) to remove SO2 from flue gas creates a product that may be used in agriculture. However, there are no reports on changes of soil chemical properties by application of petroleum coke CFB product. Two field experiments were conducted to determine elements in topsoil, subsoil, and soil water after CFB product application at 67.2 Mg/ha. Sulfur in the 0- to 60-cm and Ca, Mo, Ni, Sb, Sr, and V in the 0- to 15-cm soil layers were all increased 7 and 30 months after application. Concentrations of Ca, Mg, Ni, S, and Sr in soil water at the 60-cm depth were 2 to 4 times greater than control levels 6 months after treatment and 8 to 31 times greater 27 months after treatment. Concentrations of Al, As, Cd, Cr, Mn, and Sb were also increased in soil water 6 months after treatment at the 30-cm depth and 27 months after treatment at the 60-cm depth. Subsoil chemical properties and vadose water quality in this study were significantly changed by the surface application of petroleum coke CFB product, but the changes would not preclude the use of CFB product as a beneficial soil amendment.