A state senator is asking why schools and local governments are using artificial turf made from recycled tires while health concerns about the turf are increasing. California pays a recycling subsidy for the use of “crumb rubber” from recycled tires as a way to divert tires from landfills. But some people worry the artificial turf could pose health risks from heavy metals and organic contaminants linked to cancer and other health problems. Christopher Martinez reports from Sacramento.