In July of 2018, Andrew Thaler wrote for Southern Fried Science that there were at least two nuclear capsules, four unarmed weapons, and one armed nuclear weapon sitting on the ocean floor, that he was aware of.
His information was based on declassified U.S. Department of Defense narrative summaries of accidents involving U.S. nuclear weapons.
He noted that the documents he had access to only covered the period of time between 1950 and 1980. Any more recent data would still be classified. There is reason to believe that his estimated numbers for nuclear material in the oceans are far too low.
Business Insider in 2013 wrote that since 1950 there have been 32 nuclear weapon accidents, known as Broken Arrows, where an unexpected event involving nuclear weapons resulted in the firing, launching, theft, or loss of said weapon.
BI reported in this piece that there were six nuclear weapons that have been lost and never recovered. The time frames for the BI list continued into the 2000’s, but this is also a lowball number.
According to a 1989 article in the New York Times, however, there have been at least 50 nuclear warheads and nine reactors scattered on the ocean floors since 1956.
These were the result of various accidents on the part of U.S. and Soviet bombers, ships, and rockets, according to a study of naval accidents that was published by Greenpeace and the Institute for Policy Studies.
The study outlines 1,276 accidents, both nuclear and non-nuclear, on the part of the world’s navies, and has some, more limited, information on another 1,000 accidents. The study points out that the total number of incidents amounts to one major peacetime accident a week.
Information for the study was gathered mostly through the Freedom of Information Act, which included American intelligence assessments of Soviet naval accidents.
The authors also received information from the governments of other nations. The report said that the worst accident occurred in 1986, when a Soviet submarine sank 600 miles northeast of the Bermuda coast, depositing two nuclear reactors and 32 nuclear warheads on the bottom of the ocean.
That one accident left more nuclear material under the sea than the authors of the first two pieces posited, combined. The study also notes that it doesn’t reflect data on any of the “many hundreds” of Soviet accidents about which little is known, and suggested that the Soviet Navy has far more accidents than those of America.
The accidents are, for the most part, due to human factors, ranging from issues of faulty navigation to outright sabotage.
So far, the U.S. has admitted to knowing of one hydrogen bomb that is leaking radioactive material. That bomb was accidentally dropped into the sea south of Japan in 1965 by an aircraft carrier.
There is some likelihood that other bombs may have also begun to leak radiation into the water, and are just unknown as yet. Even if it hasn’t happened yet, the chances of such leaks will increase over time as the weapons degrade, having the potential to cause untold harm to the oceans and our planet as a whole.