The Project on Government Oversight, a non-profit organisation, has claimed that a W56 warhead with a 1,200 kiloton yield was nearly detonated last year while being dismantled at a factory less than 20 miles from Amarillo.
The organisation claims to have been told by unnamed experts with knowledge of the incident that a safety device failed when technicians applied an unsafe amount of pressure during three unsuccessful attempts to dismantle the warhead.
The Energy Department fined the plant where the incident occurred, $110,000. The Pantex plant is the only nuclear weapon assembly/disassembly plant in the US. Some of the technicians at the plant are required to work as many as 72 hours per week.