The Westley tire pile near Modesto is the largest in the western United States and one of the four or five largest in the country. Numbering 6 million, it was begun in the 1950s, because the owner believed that someday they would be worth something. At one time it contained 34 million tires, before the California Integrated Waste Management Board started reducing it through burning. The Modesto Energy Limited Partnership next to the Westley tire pile is the only plant in California that burns tires to make energy. Tires are also cheaper to burn than oil or coal, but not cheaper than natural gas, which is driving down the cost of producing electricity.
Tire fires are difficult to put out and can burn for months.
They send off billows of stinking black smoke full of polynuclear aromatic hydrocarbons, benzene and other toxic pollutants. They ooze oil, and if water is used to fight the fire, the oil travels with it. The fluid then contaminates groundwater, surface water and soil. A fire at the Royster tire pile near Tracy has been burning for over a year and has consumed 7 million tires. In May 1996, a million and a half tires burned at the Choperena tire pile, in western Fresno County.