Many other chemists were working on developing this technology including Ernst Eger of Uniroyal and Goodyear chemist James Merrill. In 1941, Eger’s patent, published after the war in 1946, was for a “Puncture Sealing Gas Tank”. It utilized a two-layer system of rubber compounds that were encased in a metal outer shell over the wing of the aircraft. By 1942, the War Production Board implemented this technology in the Goodyear produced Corsair fighters and other aircraft of the time, including the P-39. The Fireproof Tanks were made of laminated self-sealing layers of rubber, reinforcing fabric, one of vulcanized rubber and one of untreated natural rubber which absorbed the fuel, causing it to swell and expand, sealing the puncture.
Not all aircraft were fitted with the self-sealing tanks because they were heavier than the non-sealed tanks, potentially limiting maneuverability and flight time. However, the craft with the self-sealing tanks were able to take more enemy fire than those without and sustained far more damage, allowing the pilots to safely return to base. This technology is still used today in modern jet fighters however, modifications and newer technologies have been created to accommodate the higher altitude flying.