Shell, mortar, or grenade fragments caused 60 percent of the fatal wounds, the statistics revealed, with the remainder being charged to rifle or machine gun fire. It was futile to hope for lightweight protection against high-velocity bullets. But researchers hoped that plastic body armor could stop enough shell or mortar fragments to reduce serious wounds to light wounds while preventing light wounds altogether. Doron and nylon were the materials approved by the joint Army-Navy committee. The first, named in honor of Colonel Doriot, consisted of laminated layers of glass cloth filaments, bonded under heavy pressure to form a thin, rigid slab. That a 1/8-inch thickness could stop and partially flatten a submachine gun bullet with a muzzle velocity of 1,150 feet per second was demonstrated by ballistic tests at a range of eight yards. The committee recommended 12-ply, laminated, basket-weave nylon for use where flexibility was required. Both the doron and nylon protected the wearer by offering enough resistance to absorb the energy of the missile, which spent itself at the impact. Thus the shock was spread out over too large a surface for a penetration, although the wearer could receive a bad bruise. If a penetration did result from a missile of higher velocity, its effects would be much reduced in severity. Aircraft pilots and crewmen, who could tolerate more weight than foot-sloggers, were first to benefit. Flak suits and curtains were being manufactured in quantity for airmen by 1944, and the Eighth Air Force claimed a 50 percent reduction in casualties as a result. The infantry stood most in need of protection. Statistics from 57 U.S. divisions in the European theater of operations during World War II indicated that foot soldiers, comprising 68.5 percent of the total strength, suffered 94.5 percent of the casualties. It was further established that shell or mortar fragments caused from 61.3 to 80.4 percent of the wounds. Unfortunately, progress lagged for the ground forces, owing to conflicting requirements. Several prototype armored vests were submitted and rejected. The Marine Corps planned to conduct combat tests in the spring of 1945 by providing the ordinary utility jacket with sheaths to hold slabs of doron. A battalion of the 2d Marine Division had been selected to wear the garment on Okinawa, but the experiment was interrupted by the end of the campaign. The Navy and Marine Corps renewed their research in 1947 at Camp Lejeune. There a new ballistics center, established for the development and evaluation of body armor, was set up by the Naval Medical Field Research Laboratory (NMFRL). Lieutenant Commander Lewis was placed in charge of experiments.