https:// www.cbsnews.com/news/the-smallpox-threat-how-serious/

That is why Russian scientists, during the 1980s, turned the smallpox virus into a biological weapon.

"They had a factory that could produce as much as 80 to 100 tons of smallpox virus in a year. And it was intended for use in intercontinental ballistic missiles which would be shot over, would come down, break up, and little melon sized containers containing the virus would then spin and open up and spread an aerosol of smallpox over a wide area."

https://en.wikipedia.org/wiki/Mike_Wallace