A new report on the safety of school supplies claims some Playskool brand crayons tested positive for asbestos.Playskool crayons purchased at a Chicago Dollar Tree store tested positive for trace elements of the dangerous substance, according to the U.S. Public Interest Research Group.The group tested six different brands of crayons, which were purchased at stores in several states. Playskool was the only one that tested positive for asbestos.Three years ago, similar tests found many different brands tested positive for asbestos. This year, only one brand tested positive.Hasbro, the parent company of Playskool, said it's looking into the report.