Sites with Special Exposure Cohort (SEC) Status:
- Revere Copper and Brass, 1943-1954 (Detroit, Michigan)
- Rocky Flats Plant, 1952-1966 (Golden, Colorado)
- S-50 Oak Ridge Thermal Diffusion Plant, 1944-1951 (Oak Ridge, Tennessee)
- SAM Laboratories, Columbia University, 1942-1947 (New York City, New York) (a/k/a SAM Laboratories; Special Alloyed Materials Laboratories; Substitute Alloy Materials Laboratories)
- Sandia National Laboratories, 1949-1962 (Albuquerque, New Mexico)
- Savannah River Site, 1953-1972 (Aiken, South Carolina)
- Simonds Saw and Steel Co., 1948-1957 (Lockport, New York)
- Spencer Chemical Co., Jayhawks Works, 1956-1961 (Pittsburgh, Kansas)
- St. Louis Airport Storage Site (SLAPS), 1947-1971 (St. Louis, Missouri) (a/k/a Robertson Airport; Robertson Storage Area)
- Standard Oil Development Co. of NJ, 1942-1945 (Linden, New Jersey) (a/k/a Bayway; Exxon)