Abstract: A mixture of boiling water and a gelling agent, such as the polysaccharide agar, are mixed and poured into a mold and allowed to cool and gel. The gelled mixture is then removed from the mold and frozen, after which it is placed in a freeze drier where it is completely sublimated to remove therefrom all moisture. The resultant freeze dried material is extremely light in weight, is biodegradable, and exhibits favorable fire retardant properties.