Operation Sea-Spray

Operation Sea-Spray was a 1950 U.S. Navy secret biological warfare experiment in which Serratia marcescens and Bacillus globigii bacteria were sprayed over the San Francisco Bay Area in California in order to determine how vulnerable a city like San Francisco would be to a bioweapon attack. There has been speculation that the experiment may have contributed to one death and at least ten illnesses.

Military test

Starting on September 20, 1950, and continuing until September 27, the U.S. Navy released the two types of bacteria from a ship offshore of San Francisco. Based on results from monitoring equipment at 43 locations throughout the city, the Army determined that San Francisco had received enough of a dose for nearly all of the city's 800,000 residents to inhale at least 5,000 of the particles. This is within the range of infectivity for anthrax.

Illnesses

On October 11, 1950, eleven residents checked into Stanford Hospital near San Francisco with very rare, serious urinary tract infections. Although ten recovered, Edward J. Nevin, who had recent prostate surgery, died three weeks later from a heart valve infection. The urinary tract outbreak was so unusual that the Stanford doctors wrote it up for a medical journal. None of the other hospitals in the city reported similar spikes in cases, and all 11 victims had urinary-tract infections following medical procedures, suggesting that the source of their infections was inside the hospital. Cases of pneumonia in San Francisco also increased after Serratia marcescens was released, though a causal relation has not been conclusively established.