Ignitable liquids are prevalent in all industrial occupancies. Historically they have been shipped and stored in metal drums; however, economic factors are driving a greater use of composite intermediate bulk containers (IBCs) instead. Composite intermediate bulk containers typically consist of a 275-gal high density polyethylene bottle within a steel tubular structure. FM Global has found that commercially available, non-FM Approved, intermediate bulk containers fail when exposed to fires. Testing has shown that the time to failure and the failure mechanism of high density polyethylene IBC bottles is a function of the fluid being stored within them. Hydrocarbon based fluids tend to permeate into the material as the polyethylene is heated, softening it, thus resulting in large tears. Water has no interaction with the polyethylene and the failure mechanism is attributed solely to melting of the polyethylene presumably at a local void in the sample. In the absence of a suitable commercially available unit, FM Global seeks to identify potential polymers that could be used to develop an intermediate bulk container for use in transportation and storage of ignitable liquids, that meet the performance criteria outlined within the new FM Approvals, Approval Standard 6020, Intermediate Bulk Containers. Important considerations for the material selection, in addition to fluid compatibility at elevated temperatures, include: 1.Overall weight of the final unit 2.Overall cost of the final unit 3.Ease of construction This presentation will discuss the hazards associated with composite IBCs, the results from the original testing with the HDPE and recent R&D testing exploring new polymers. The results from these tests indicate that thicker materials, or multi-layer designs, may provide an increased benefit in the final unit performance; however, the added benefit must be balanced against the increased weight of the unit and thus potential transportation issues.