Why officials are leaving 47,000 toxic barrels in the ocean

Key Points:

• Approximately 47,800 steel drums containing low-level radioactive waste were dumped off the coast of San Francisco between 1946 and 1970, scattered across 1,400 square kilometers of seafloor at depths from 100 to over 2,000 meters.
• The barrels, weighted with concrete and intended for one-way disposal, contained various radioactive materials including tritium and other isotopes, but detailed records of their contents and exact locations are lacking due to poor documentation practices at the time.
• Surveys and submersible investigations have found some drums intact while others have corroded, releasing contaminants; however, official assessments since the 1980s have generally downplayed the public health risks, estimating significant decay of radioactivity.
• Studies in the 1990s detected unusual isotope ratios in marine life near the dump sites, but the health risks from consumption were considered small, and some researchers questioned whether the barrels were the contamination source.
• Despite concerns about both radioactive and toxic chemical pollution, no salvage or cleanup operations have been attempted due to the risks of disturbing the barrels, and international bans on ocean dumping now focus on monitoring rather than retrieval.