The shoes we are selling have the standard Vibram Sole that is not made with B2EARTH rubber. However here is some information about B2EARTH rubber.
The B2EARTH rubber blend does not begin to decompose until it is exposed to an environment that the process composting can begin. Essentially the boots have to be buried in soil where they would be exposed to insects, earthworms and microorganisms. B2EARTH rubber does not biodegrade: with the passing of time and through the seasons; once exposed to atmospheric conditions such as humidity and heat outside and inside the shoe; in general, in any ordinary circumstance. This is link to the B2EARTH FAQ on the B2EARTH web site. http://www.b2earth.com/index.php?option=com_content&view=article&id=68&Itemid=187&lang=en