In the environment, sodium hypochlorite is acutely toxic to fish. The chlorine in bleach can also bind with organic material in the marine environment to form organochlorines, toxic compounds that can persist in the environment. Chlorine use is a particular concern for those who live in areas such as Victoria, where there is not even primary treatment of sewage wastewater before it is discharged into the ocean.
There may be some circumstances where bleach use is necessary for disease control, but there is little need for it on a regular basis. Tests have shown that washing counters and other surfaces with soap and water removes most bacteria and there are a number of oxygen-based alternatives for laundry uses of bleach.