in 2011. The system has been endorsed by the Portland Bureau of Emergency Management. It is promoted by the volunteer advocacy group PHLUSH (Public Hygiene Lets Us Stay Human) for reasons of safety, affordability, and matching ecological sanitation principles. Usage and maintenance The bucket is emptied when it becomes full or emits excessive foul odor; usually once a day for large families, and about once a week for smaller families. Some sources say that it averages once per week per person per five-gallon bucket. The quantity of excreta varies widely depending on the amount of fiber in the local diet. If the bucket has a liner, then emptying is more hygienic in areas with poor water access for cleaning the collection chamber (bucket) than without a liner, as the bag could be sealed with a knot and the bucket would remain fairly clean. To minimize offensive odors and prevent the spread of disease, the material in the bucket can be covered with some covering material after each use, such as quick lime, wood ash, finely crushed charcoal or fine sawdust (similarly to the operation of a urine-diverting dry toilet). Disposal or treatment and reuse of collected excreta When the bucket is full, it can be covered with a lid and stored away until the collected waste can either be disposed of (e.g. by burial) or treated for safe reuse, e.g. via composting the material. Health aspects An unimproved, open bucket in which excreta are not covered by carbon matter does not offer much protection to the user from the pathogens in the feces, which can lead to significant health risks. Flies can access the contents unless it is kept securely covered (e.g., by a toilet lid and/or adequate carbon matter). There is also the risk that the bucket can tip over and spill its contents; an improved system encloses the bucket inside something which is securely bolted to the floor. Unhygienic emptying and disposal practices add further opportunities for pathogens to be spread, for example, if the bucket is not cleaned after each use or if a liner is not used. For these reasons, unimproved bucket toilets were not considered as improved sanitation systems according to WHO and UNICEF for monitoring access to basic sanitation as part of Goal 7 of the Millennium Development Goals. At the time of these goals, IAPMO had not yet published new standards for acceptable