LOS ANGELES — As the conflict in Iraq continues, a shortage of carbon fiber material has occurred that is now limiting production of advanced, clean buses, according to a report by Weststart/CALSTART. A number of companies that manufacture high-pressure tanks used for natural gas vehicles are unable to supply vehicle manufacturers with those storage vessels, delaying delivery of buses. High-quality carbon fiber materials used in the fabrication of the high-pressure storage tanks are in short supply, and much has been requisitioned for the war effort. Gearing up to manufacture carbon fiber is an expensive and time-consuming undertaking; and because of the strategic importance of these products, manufacturing licenses are tightly controlled. Currently, approximately 80 percent of the global market for this material is controlled by three companies, all of which are Japanese, using a process that was developed and licensed in the U.S. Fewer buses may put some fleets, such as the Los Angeles Metropolitan Transportation Authority (METRO), in violation of court order to replace its diesel-powered buses and expand its fleet to address ridership issues. Re-engineering the buses to use other types of tanks would be difficult, and the substantial additional weight would decrease mileage, increasing refueling demands, and cut overall service efficiency.