He institutionalized a revolutionary idea, pre-paid medical care for workers, which soon expanded beyond workers. For many workers, this was the first time they had seen a doctor. The Kaiser Richmond Field Hospital for the Richmond Shipyards was financed by the U.S. Maritime Commission, and opened on August 10, 1942. By August 1944, 92.2 percent of all Richmond shipyard employees had joined the plan, the first voluntary group plan in the country to feature group medical practice, prepayment and substantial medical facilities on such a large scale. By 1990, Kaiser Permanente was still the country's largest nonprofit HMO. In part due to wartime materials rationing, the Field Hospital is a single-story wood frame structure designed in a simple modernist mode. The Field Hospital operated as a Kaiser Permanente hospital until closing in 1995, after a new hospital was built downtown. The Maritime and Ruth Powers Child Development Centers were two of approximately 35 nursery school units of varying sizes established in the Richmond area during World War II in order to provide child care for women working in the Kaiser shipyards. The Maritime center was funded and constructed by the Maritime Commission as part of a larger development that also included housing, an elementary school and a fire station. The temporary housing was demolished after the war but a larger permanent housing complex remains as do the other buildings. The Maritime Child Development Center, a wood frame, modernist style building operated by the Richmond School District, incorporated progressive educational programming, and was staffed with nutritionists, psychiatrists and certified teachers. It had a capacity of 180 children per day. At its peak, with 24,500 women on the Kaiser payroll, Richmond's citywide child care program maintained a total daily attendance of 1,400 children. Unlike the federally funded WPA day care facilities implemented during the New Deal, the World War II centers were not intended for use by the destitute, but for working mothers. The Kaiser-sponsored Child Care Centers, particularly those at Kaiser's industrial sites in Vanport, Oregon, and Vancouver, Washington, gained a reputation for innovative and high quality child care. The center is still in operation today. Lucretia Edwards Shoreline Park, named in honor of local community activist Lucretia W. Edwards, honors the wartime contributions made by the Bay Area Shipyards during World War II. In addition to the local Richmond Shipyards, shipworker's bootprints with plaques set in the sidewalks and long low seating walls point visitors to the other Bay Area shipyards. The following inscriptions are engraved into the concrete walls:   All of the following are filed under Richmond, Contra Costa County, CA: