I would be interested in your thoughts on some claims that the Japanese balloons found over rural areas in the western US (during WWII) did have toxic biological agents—but that they were ineffective because they were in remote areas.
Oh they were contaminated, you never know when you will get lucky, but it was not a serious attempt.
The one in September was going to be quite serious.
Bubonic plague in California and Hawaii. I believe Australia was also targeted.
With all the planes and cargo moving in and out of those locations it would be world wide in days.