Worst? This guy right here:
Thomas Midgley.
He was absolutely brilliant. This brilliant man invented leaded gasoline, and which is essentially gasoline with lead in it. Lead exposure can lead to neurological disorders and cause extensive physical harm. So when gas combusts, it releases lead into the air.
But it gets worse! He was also the inventor of Freon, which is useful in refrigerators- but wait! Freon is a CFC, or a chlorofluorocarbon. What do CFCs do? They destroy the ozone layer and allow more UV light to penetrate the atmosphere.
Pretty bad. But the next man makes Midgley look like a loaf of bread in terms of harm caused.
Dr. Shiro Ishii, a man who cared nothing for ethics.
A Japanese scientist. To conduct wartime experiments he unleashed medical torment upon infants, children, pregnant women, everyone! He would freeze limbs and thaw them to study frostbite. He would burn victims and study the burns. He would unleash chemical weapons over crowds to “study” the effects. He would perform surgery without anesthesia , inject bubonic plague, freeze, burn, and ultimately kill thousands.
Quite the sadist if you ask me.