WW2
Textbook lesson (that you'll never read in a textbook): This is what happens when you let scientists off-the-leash ...
Japan's Unit 731 in Manchuria - with it's 3000 scientists is a good example. Acting as a DIY intermediate species, these geniuses engineered/released plague-infected fleas. Wound up killing 10 000 Chinese at least.
Meanwhile back at the lab: STAGE 3 TRIALS were conducted on POW's - inoculated with u-name-it deadly bio-bugs from anthrax to cholera - to evaluate promising candidates.
At the hearings an official repented , said: it was most regrettable from the view point of humanity
So prophetic!
The UK was right into it - developing offensive bio-warfare tech like there was no tomorrow. Porton Down Bio-Research Centre's Anthrax Island is one example. Winston Churchill himself, personally ordered the great-leap-forward in bio-warfare. Bombs laden with anthrax spores dropped by airplanes, or mortar-launched (which proved to be the best), released a white cloud of fine powder on tethered sheep . Which died horrible anthrax deaths, needless to say. So it was a big success.
Denied/lied about for decades, blamed on unsanitary Greeks, natural causes - everything else was a conspiracy theory - even as livestock in nearby areas started mysteriously dropping dead.
Meanwhile: the anthrax spores dispersed on the island, lived happily on.
Defense Ministry reluctantly fessed-up when Dark Harvest activists left a bucket of contaminated soil from the island outside Porton Downs Lab HQ in Wiltshire. Technically an act of terrorism - but the Defence Ministry had denied the island was contaminated. Caught in their own conundrum, Defence finally pledged to clean the island up. Do better next time ...
First the military tried scorch-earthing it - setting the whole island alight - but that failed - so , quote: the land was decontaminated by using formaldehyde - which makes a great Govt oxymoron at least.
The British were also accused by the Germans of trying to import yellow fever into India. The UK denies it.
Funnily enough, Hitler was the only one who refused to develop bio-warfare tech. He thought it was unethical. What does that tell ya?