My vote goes to Bayer for knowingly and willingly selling H.I.V tainted medicine in the 1980s just to get rid of their inventory, not caring about the hundreds or thousands of people they infected.

Possibly sadder is that the FDA actively helped Bayer to try and cover the whole thing up.

http://www.nytimes.com/2003/05/22/business/2-paths-of-bayer-...