Lead was in short supply, so the Petroleum Warfare Department decided to seek an alternative that made use of cheaper and more readily available materials as a backup system to Hais, which was itself a backup system. Bernard J. Ellis, the chief engineer of the Burmah Oil Company, was convinced that a flexible pipeline could be built from mild steel, which was more readily available than lead. His pipe was 3+1⁄2 in (8.9 cm) in diameter, with 0.212-inch (5.4 mm) walls.