The Titan I was a US first generation ICBM using at 2-stage rocket powered by kerosene and liquid oxygen. It carried a 3800kg 9MT W-53 warhead and had a range of 8,850km. The missiles had to be fueled before launch, a a dangerous process requiring 30 minutes. Titan II introduced the use of a non-cryogenic hypergolic fuel, though this had problems with several serious accidents. It was decommissioned in 1987 and replaced by the MX Peacekeeper solid fuel missiles.