150K Tons of Radioactive Waste Dumped in Atlantic Seen Oozing in Ocean Decades Later

An estimated 150,000 tons of radioactive waste dumped into the ocean now appears to be oozing.

According to a report from ScienceAlert, in the decades after World War II, more than 200,000 barrels of low-level radioactive waste were dumped at the bottom of the Atlantic Ocean.

The dumping, which occurred between 1949 and 1982, included a mix of radioactive materials, like cesium-137, plutonium isotopes and tritium, with many of the barrels corroding and disintegrating, spilling the toxic contents across the seafloor.

According to the outlet, many of these materials can exist in the ocean for thousands of years, with the barrels becoming part of the ecosystem and serving as habitats for various forms of marine life.

The issue has been a hot topic for researchers in the field in recent years. In 2025, nuclear engineer Patrick Chardon and marine geologist Javier Escartín of the French National Center for Scientific Research spearheaded an investigation that resulted in a month-long expedition, which saw researchers sweep across the seafloor, mapping and photographing the barrels, collecting water, sediment, fish and crustaceans from the surrounding area.

They ultimately located and mapped 3,355 barrels, but they weren’t done yet. According to France’s main state research organization, CNRS, the researchers returned in May 2026 aboard the Pourquoi Pas?, using the three-person Nautile submersible. During their mission, they made more than 20 dives and descended more than 4,700 meters to inspect the barrels and collect samples.

Researchers detected radioactive signals from cobalt-60 and niobium-94 that they were able to specifically link to the dumped waste, while cesium-137 and americium-241 were also detected.

But even with significant radioactive signals around the barrels, ScienceAlert reported that the levels of radioactivity weren’t high enough to pose a risk to the scientists collecting and testing samples, with neither Nautile nor the instruments it carried showing signs of contamination.

Analysis of the dumping site is ongoing and will determine what kind of impact the radioactive waste has had on marine life and their surrounding habitats.