"The single biggest use of scrap tires in the United States and the European Union is as fuel. Environmentally or even economically speaking, it is not the best method of reclaiming scrap tires, but it beats the alternative of disposing or dumping unused tires.
Whole tires and rough tire chips are used at cement kilns, pulp and paper mills, power plants, waste-to-energy plants and industrial boilers. In 2000, approximately 47 percent of the 273 million scrap tires generated in the United States were burned for fuel.
Cement kilns are considered good places to use TDF because the ash is incorporated into the final product, there is no waste to dispose of, according to the Texas Natural Resource Conservation Commission."