Yes they are becoz In Nuclear Bombs two things are happen ,they are Nuclear Fisson or Nuclear Fusion both are the most dangerous.
As they release tremendous amount of heat which can be controlled in Nuclear Reactors but while in Bombing it cannot be Controlled.
nuclears bombs are very dangerous.
if a nuclear bombs blasts , then it will effect our lives for millions of years.
if the radioactive rays of the nuclear bomb is smelled by a pregnant woman then , her baby will be born as an handicapped.
through this example , u can understand that how dangerous are nuclear bombs.