MW-Day/Ton burnup. Such low irradiation times limit the amount of additional neutron capture and therefore buildup of alternate isotope products such as Pu-240 in the rod, and also by consequence is considerably more expensive to produce, needing far more rods irradiated and processed for a given amount of plutonium. Submarine crew members routinely operate in proximity to stored weapons in torpedo rooms, in contrast to the air force where exposure to warheads is relatively brief. The first models were delivered in December 1983 and the Mod 0 went into full production in March 1984. Production of the W80 was completed by September 1990, although the exact date at which the respective Mod 0 and Mod 1 runs ended is not clear. A total of 1750 Mod 1 and 367 Mod 0 devices were delivered; 1,000 Mod 1 devices were deployed on the original ALCM, another 400 on the later ACM, and 350 Mod 0s on the Tomahawk. Some of the original ALCMs would later have their mod 1 warheads removed and instead be fitted with conventional warheads producing the CALCM conversion. Under START II only 400 ACMs would have retained their nuclear warheads, and the rest would have been converted to CALCMs and their warheads removed to the inactive stockpile. 2007 nuclear weapons incident On August 30, 2007, six cruise missiles armed with W80-1 warheads were mistakenly loaded onto a B-52 and flown from Minot Air Force Base, North Dakota, to Barksdale Air Force Base, Louisiana, on a mission to transport cruise missiles for decommissioning. It was not discovered that the six missiles had nuclear warheads until the plane landed at Barksdale, leaving the warheads unaccounted for over 36 hours. 5th Bomb Wing subsequently failed its nuclear surety inspection in late-May 2008. 2nd Bomb Wing from Barksdale Air Force Base took over the role until the wing was recertified on the 15th August 2008. W80-4 Refurbishment and LRSO In 2014 a life extension program for the W80-1 was started and the LEP warhead was given the W80-4 designation. The warhead will be used on the new AGM-181 LRSO cruise missile. First production unit is estimated in 2025 and production should finish in 2031. According to public descriptions of the program, the warhead will offer no increased military capability, only refurbishing and updating components, and increasing weapon safety and reliability. In FY2022, the National Nuclear Security Administration requested funding for the