Sites with Special Exposure Cohort (SEC) Status:
- Nevada Test Site (NTS), 1951-1992 (Mercury, Nevada)
- Norton Co., 1945-1962 (Worcester, Massachusetts)
- Nuclear Materials & Equipment Corp. (NUMEC) – Apollo, 1957-1983 (Apollo, Pennsylvania) (a/k/a Atlantic Richfield Corp. (ARCO); Babcock & Wilcox)
- Nuclear Materials & Equipment Corp. (NUMEC) – Parks Township, 1960-1980 (Parks Township, Pennsylvania) (a/k/a Atlantic Richfield Corp. (ARCO); Babcock & Wilcox)
- Nuclear Metals, Inc., 1958-1979 (West Concord, Massachusetts)
- Oak Ridge Gaseous Diffusion Plant (K-25 Site), before February 1, 1992 (Oak Ridge, Tennessee) (a/k/a East Tennessee Technology Park (ETTP))
- Oak Ridge Hospital, 1950-1959 (Oak Ridge, Tennessee)
- Oak Ridge Institute for Science Education (ORISE), 1950-1956 (Oak Ridge, Tennessee) (a/k/a Oak Ridge Associated Universities (ORAU); Oak Ridge Institute for Nuclear Studies (ORINS))
- Pacific Proving Grounds, 1946-1962 (Marshall Islands, Marshall Islands) (incl. Bikini Atoll, Enewetak Atoll, Johnston Island (nuclear weapons testing activities only), and Christmas Island (U. S. nuclear weapons testing activities only))
- Paducah Gaseous Diffusion Plant, before February 1, 1992 (Paducah, Kentucky)
- Pantex Plant, 1958-1983 (Amarillo, Texas)
- Piqua Organic Moderated Reactor, 1966-1969 (Piqua, Ohio) (a/k/a Piqua Nuclear Power Facility)
- Portsmouth Gaseous Diffusion Plant, before February 1, 1992 (Piketon, Ohio)