US Dumped 47,800 Radioactive Waste Drums Off San Francisco, Scattering 540 Terabecquerels Across Seafloor
Updated
Updated · spacedaily.com · Sep 21
US Dumped 47,800 Radioactive Waste Drums Off San Francisco, Scattering 540 Terabecquerels Across Seafloor
2 articles · Updated · spacedaily.com · Sep 21
Summary
Roughly 47,800 radioactive waste containers were dumped by the United States between 1946 and 1970, leaving debris spread across about 1,400 square kilometers of seabed west of San Francisco.
Most were 55-gallon steel drums dropped 25 to 60 miles offshore at depths from 90 to 1,800 meters, designed only to reach the bottom before currents diluted their contents rather than to contain them permanently.
Records are incomplete because crews often missed designated dump sites and the Navy kept little detailed documentation; later sonar and submersible surveys found both intact drums and others fully corroded away.
A 1981 federal review said about 90% of the radioactivity had decayed to negligible levels, while a 1996 study found unusual isotope signatures in fish and mussels but still projected human doses of only about 0.03 millisieverts a year.
Ocean dumping of radioactive waste was banned globally in 1994, but no agency plans to retrieve the drums, leaving monitoring as the standing policy inside and near protected Farallon waters.