Following increasing concerns about the safety of recycled tire material used on synthetic turf fields, the Obama administration announced Friday a federal study to look into potential health risks. The material in question -- ground-up waste tires -- has been a source of debate across the country since late 2014, when parents and health and environment advocates began demanding studies about whether repeated contact with the material could cause cancer. That's the year a University of Washington soccer coach came forward with a list of a few dozen young athletes with cancer who regularly played on turf fields -- surfaces...