Artcare foamboard

I have a question about the Artcare foamboard
<URL:http://www.artcare.com/html/home2.html> with microchamber
technology. Is it safe to use in a preservation framing package? The
core is polystyrene and the offgassing from it has been a troubling
question for me as to if it is safe even with the zeolite
microchamber covering. The thickness and ease of using the foamboard
is great and a lot of framers, from what I understand, are using it
as "archival" backing board. If a paper conservator could shed a
little light on this I would really appreciate it.


                                  ***
                  Conservation DistList Instance 13:54
                  Distributed: Wednesday, May 3, 2000
                       Message Id: cdl-13-54-015
                                  ***