The secret Cold War bioweapons test that exposed millions in the Bay Area

The bacterial species released was Serratia marcescens. If you've ever seen a pinkish build up in your shower these bacteria are to blame. Normally doesn't affect healthy people but people with compromised immune systems aren't so lucky.

Operation Sea-Spray was the US Army operation that dispersed S. marcescens over SF. The Army has done similar tests with Bacillus globigii and even carcinogenic chemicals.