A nuclear weapon is a very precise instrument, but there's a huge amount of extremely high explosives involved in some designs, especially those using a plutoni

A nuclear weapon is a very precise instrument, but there's a huge amount of extremely high explosives involved in some designs, especially those using a plutonium core. Those alone are extremely dangerous, especially because a "fizzle", or incomplete detonation, will release scary amounts of highly radioactive material. Low yield, high fallout. Conventional explosives are a lot more dangerous, it's true, because they can be set off by a variety of things. A nuclear weapon requires a very aggressive initiator perhaps by design, but it's not like a nuke sitting at the bottom of the ocean is entirely safe.