Here’s one WMD in the U.S., for sure:
“B-52 Crash Remembered: Adam Mattocks, pilot aboard the B-52 that crashed on Jan. 24, 1961, in eastern North Carolina, last week gathered with crash witnesses and first responders at the mishap scene to remember the three airmen who perished that day. Five airmen survived, including Mattocks; he’s the only one still alive after all these years. The B-52, carrying two Mk 39 nuclear bombs, was on an alert mission along the US East Coast that fateful day when it experienced a massive fuel leak, reported WNCT, eastern North Carolina’s TV news station 9. The bomber went down in Pikesville as the aircrew attempted to land it at Seymour Johnson Air Force Base, just outside of Goldsboro in the eastern part of the state. The Air Force recovered one of the two nukes; but the second lodged itself deep in the swampy earth, preventing its recovery.”
I’ve heard that folks have recently been trying to recover that bomb. It contains tens of millions of dollars worth of nuclear material (lithium-6 deuteride solid fuel and a multi-ton uranium tamper; the plutonium pit was removed). Unfortunately (or fortunately) the exact location of the bomb has been lost to history. Recovery may be dangerous. In the case of the bomb that was recovered only one safety was still working.