I know that this has come up in the past on the original Knock-Off Wood site because I remember reading about it and it sparked my interest. I have been researching a local source for formaldehyde-free plywood and MDF, and I ran across some info that is fantastic if this is a concern of anyone out there. Orange carries the brand PureBond plywood that meets this criteria!!! They carry it at my local store here in Ohio, so chances are it is available where you are. If you search for PureBond plywood on their website and then click on the product that comes up, it will go into more detail about the specifications.
Now if I could only find some FF MDF...anyone have some info about that? I've found a company that makes it, Sierra Pine, and it is called Medex and Medite. They started making this years ago, so I am thinking there has to be something newer out there that would possibly be more widely available.