I recall when my MIL had undergone breast cancer surgery in a San Francisco hospital in 1984 she became infected with the bacteria Serratia marcescens (http://www.ncbi.nlm.nih.gov/pubmed/21976608). The bacteria once thought benign was used by the U.S. Navy in bacteriological warfare agent dispersal testing. The test was titled Operation Sea Spray involving bursting balloons containing Serratia marcescens over the San Francisco Bay Area on September 26 and 27 1950. By September 29 the bacteria began causing severe urinary tract infections of hospitalized patients in the test area.

https://en.wikipedia.org/wiki/Serratia_marcescens The pertinent information is toward the bottom of the article.

Quoting the article: "Since 1950, S. marcescens has steadily increased as a cause of human infection, with many strains resistant to multiple antibiotics.[1] The first indications of problems with the influenza vaccine produced by Chiron Corporation in 2004 involved S. marcescens contamination."

This is the bacteria my MIL contracted during surgery. By 1985 S. marcescens had destroyed her bladder which was removed. She was sent home with an urostomy, and a supply of antibiotics I had to mix and inject twice daily. When her incision did not heal in the presence of the bacteria, the superficial sutures were removed and my wife had to pack the open incision with gauze strips saturated with a dilute sodium hypochlorite solution provided by the pharmacy. This caused the bedroom to have the aroma of a laundry. So we know that sodium hypochlorite is a medically approved treatment for some conditions.

If you live in a area with municipal water treatment, you are drinking either chloramines (http://water.epa.gov/lawsregs/rulesregs/sdwa/mdbp/chloramines_index.cfm) or chlorine, either from injection of chlorine gas or a dilute solution of sodium hypochlorite into the finished water. I operated a water plant that used sodium hypochlorite at a dose that would maintain a residual of 0.5 ppm after 30 minutes of contact time (set by automated on-line analyzer). So every time you drink the water you are drinking dilute bleach. I also installed an ultraviolet light sanitation unit that killed chlorine resistant organisms and their oocysts by scrambling their DNA so they couldn't reproduce. While some use ozone (such as bottled water producers) for water disinfection, ozone is a reactive gas and breaks down within about 20-30 minutes leaving no residual. Chlorine or chloramine is mandated in a municipal system to provide a measurable residual throughout the distribution system as confirmation that the system remains disinfected. Chlorine is good for more that bleaching your shorts.