Indiana piles up a mountain of used tyres every year and spends a mountain of cash trying to get rid of them. The Indianapolis Star reports that now, five schools in the state will become the proving ground for a novel experiment in recycling -- grinding up the tyres into crumb-size bits of rubber and sprinkling them on athletic fields, providing softer playing surfaces that still allow grass to grow. Americans throw away more than 240 million tyres every year, creating health and safety problems. Some states have found other uses for the rubber -- burning it as fuel, for example -- but in Indiana, recycling efforts have been limited. Beyond the environmental benefits, coaches say the new process is good medicine for their players. "The kids don´t slip and slide, and they don´t tear up the field," said Dick Dullaghan, football coach at Ben Davis, one of three Marion County high schools sharing in a US$90,000 grant from the Indiana Department of Environmental Management. The grant is a first for Indiana, where the focus has been on cleaning up tyre dumps -- at a cost of US$7 million in the past five years -- instead of recycling. Hoosiers throw away about 6 million tyres a year, often into dumps that become breeding grounds for mosquitoes that can carry such illnesses as the West Nile virus. The tyres easily catch fire, releasing hydrocarbons that cause thick black smoke and mix with the water from fire hoses to contaminate the soil. "They burn hot, and they burn slow," said Brownsburg firefighter Steve Milstead. "There´s not much you can do about them except let them burn out." In 1994, a tyre fire in an East Chicago warehouse took three weeks to extinguish. Unlike other states, Indiana hasn´t found many alternative uses for discarded tyres. In Illinois and Michigan, for example, tyres are cut into 2-inch chips, mixed with coal and burned in furnaces as a supplementary fuel source. "We try to find the most environmentally friendly way of dealing with them," said Steven Poe, director of Indiana´s Waste Tire Management Fund, set up in 1992 through a 25-cent surcharge on the sale of each new tyre. Recycling companies cut tyres into pieces and ship them to neighboring states for use as fuel. The pieces also turn up as rubberized rocks in a variety of industrial uses. "If they can´t be turned into useful materials," Poe said, "they will be cut up and placed in covered landfills." State environmental officials plan to offer US$100,000 in grants for each of the next two years to encourage new ways to recycle. But so far, the rubberizing process - using only 35,000 tyres - is the only one to emerge, said Jim Mahern, assistant commissioner of the Indiana Department of Environmental Management. The tyres are ground into small particles called crumb rubber and spread on the fields. The theory is that the rubber will provide a safer place to practice sports and promote healthier grass at the same time. Ben Davis will get US$30,000 -- for the football field rubberized last year and a soccer field to be treated later this year. In addition, Beech Grove and Decatur Central high schools will get US$15,000 each, as will Lake Central High School in Lake County and Taylor University in Grant County. Turf Solutions, a Taylorville, Ill., firm that will do the work, says the process creates a cushion between the grass and the soil, reduces turf wear, improves traction and moisture absorption, and cuts down on injuries. Owner Jim Stepp said it takes 100,000 pounds of ground rubber, or roughly 7,000 passenger car tyres, to rubberize a standard football field. Using a crew of three, the company spreads the crumb rubber on the field, up to 40,000 pounds in a visit. The entire process takes three visits, and each field will be layered six to eight times. The process has been used in several other states, including Illinois, Texas, M