Dr. Rathje reports that Seattle's volume-based pick-up fees caused a significant drop of waste generation there. In contrast however two Arizona cities are proving that the reverse is true. Phoenix and Tucson each converted to automated container dumping systems using 90-gal carts. Although average household size in Phoenix declined by about 25% discards by the household remained the same from 1975 to 1990. When Tucson adopted the large carts the garbage generated by households in a sample study group shot up by one-third in just a few months. Dr. Rathje attributes at least part of the growth in discards to materials that otherwise wouldn't fit into smaller receptacles. He cites households having small garbage cans as being likely to save paint and chemical cans for example until a hazardous waste collection day. With the larger carts these hazardous cans seem to appear in the municipal waste much more regularly. These experiences suggest Parkinson's Law of Garbage: Garbage expands to fill the receptacles available for its containment.