what the parents have to live with is fear of the unflown. >> that's exactly right. they don't know how debilitating or dangerous these conditions can be and of course that just creates more fear. and they're just asking to just let us know. just tell us so we can make an educated decision whether or not we want our kid to continue to go to school there, whether we think it's safe qul safe, whether our child's physician thinks its safe. there was a possession to get the school to participate in a federal study. the school district pulled out of that study against the will of a lot of these parents. >> well, it's really interesting to watch. "america tonight's" lisa fletcher, thanks so much. next, hard lessons in philadelphia. can the hamp trut harsh truth of deaths ton street change minds? and christof putzel, with a second look at that free range meat and its true impact open our environment. tonight." >> we've seen the challenges philadelphia school kids face in their classrooms but like so many other big cities, philadelphia's children are also challenged by risks