Oceanography Professors William Bryant and Neil Slowey of Texas A&M University report millions of pounds of bombs and other ordnance are scattered over the Gulf of Mexico and also off the coasts of at least 16 states, from New Jersey to Hawaii.
The discarded explosives are hardly a secret, Bryant said.
"This has been well known for decades by many people in marine science and oceanography."
Military dumping of unused bombs into the Gulf and other offshore sites started in 1946 and continued until 1970 before being banned, he said.
"The best guess is that at least 31 million pounds of bombs were dumped, but that could be a very conservative estimate," Bryant said.
In addition to explosives, canisters of chemical weapons were also dumped, some of which have been damaged and may be leaking chemicals, the researchers said.
"Is there an environmental risk? We don't know, and that in itself is reason to worry," Bryant said. "We just don't know much at all about these bombs, and it's been 40 to 60 years that they've been down there."