During the time period covered in this report (1960's through early 1990's), six commercial low-level radioactive waste (LLRW) disposal facilities have been operated in the US. This report provides environmental monitoring data collected at each site. The report summarizes: (1) each site's general design, (2) each site's inventory, (3) the environmental monitoring program for each site and the data obtained as the program has evolved, and (4) what the program has indicated about releases to off-site areas, if any, including a statement of the actual health and safety significance of any release. A summary with conclusions is provided at the end of each site's chapter. The six commercial LLRW disposal sites discussed are located near: Sheffield, Illinois; Maxey Flats, Kentucky; Beatty, Nevada; West Valley, New York; Barnwell, South Carolina; Richland, Washington.