It is Homasote 'ICE DECK'. MSDS here:
http://www.homasote.com/msds.pdf
Per manufacturer, the material is made from ground up newspaper and held together with a wax-type bond.
I have had a sore/dry throat and nausea since Friday(but it is getting better), and my daughter has been to doctor(and out of school), but we believe she has cold/flue.