Mushrooms Become Source for Eco-Building

Gavin McIntyre, left, holds a growing sample of organic insulation, while Eben Bayer shows off the finished product, at Rensselaer Polytechnic Institute in Troy, N.Y., Thursday, May 17, 2007. The two created their patented "Greensulate" formula, an organic, fire-retardant board made of water, flour, oyster mushroom spores and perlite, a mineral blend found in potting soil, and are hoping the invention will soon be part of the growing market for eco-friendly products. (AP Photo/Mike Groll)