[tarheelswamprat]

This story is BS, as many others have pointed out. However, back in the 1950's or 60's (don't remember exactly when) there was an accident in New Mexico involving a hydrogen bomb which did cause loss of life. The bomb was being transported in a cargo plane to Los Alamos when it broke free from its restraints and slid out the cargo bay door. It landed on a cow, I believe it was actually a rancher's prize bull, and killed it.

[COEXERJ145]

It was 1957 and was a Convair B-36. The weapon was accidentally released and went crashing through the bomb bay doors. Thankfully the weapon didn't have the necessary capsule inserted so it couldn't go nuclear but the high explosives did go BOOM.

IIRC it was either a Mark-14 or Mark-17 weapon but I need to check to be sure.