FearGod
Freedom Of Mind
The answer is in the same verse: "These things are capable of changing the whole atmosphere of the earth and their contamination would prove lethal."
other types such as grenades,explosives or bombs do not contaminate the whole atmosphere of the earth, so, He must have been refering to nuclear.
Baha'u'llah only revealed what God told Him and allowed Him to reveal.
Why Prophet Muhammad didn't reveal in Quran about Nuclear? I would say because, He only revealed what God asked Him.
But actually it is a bomb,nuclear bomb,he can say a super bomb that can change the whole atmosphere of the earth,and even saying changing the whole atmosphere
of the earth is completely nonsense.