Biodiesel is manufactured in many ways, with varying concentrations. B100 (100% pure Biodiesel) is a known stress cracking agent and if stored in our tanks, the lifespan of the tank may be shortened. Containment should be used and Peabody will warranty a heavy duty tank for the storage of 100% Biodiesel (B100) for one year from date of manufacture. If this product is stored in the tank, you must use either a welded fitting or a bulkhead fitting with a viton gasket.
Biodiesel blends or BXX (80/20) refers to a fuel that is composed of a % of Biodiesel blended into conventional fuel, B20= 20% Biodiesel. Peabody will warranty a heavy duty tank for the storage of Biodiesel blends for one year from date of manufacture. If this product is stored in the tank, you must use either a welded fitting or a bulkhead fitting with a viton gasket. Several different websites addressing the storage of Biodiesel state acceptable storage tank materials as aluminum, steel, fluorinated polypropylene and Teflon. Biodiesel in its pure form or blended is not to be stored underground in a Peabody tank under any circumstances.

Source: FAQs - Peabody