March 10 2008

Dangerous unknowns— MBARI researcher points out lack of information on chemical weapons dumps in the sea

Large quantities of chemical weapons sit on the seafloor, slowly degrading and posing a hazard to fishers and ocean scientists who stumble upon these stockpiles, according to a recent article by MBARI ocean chemist Peter Brewer and Noriko Nakayama of University of Tokyo.

Oceanographers never know what types of old military hardware (and other trash) they will find on the seafloor. MBARI geologists captured this image showing fragments from two bombs on the seafloor off the coast of Oahu, Hawaii. Image:© 2001 MBARI

After World War II, between 1946 and 1972, many countries dumped these outdated chemical weapons on the seafloor. In 1972, they signed the London Convention forbidding further ocean disposal. Although some disposal sites have been well-studied, little is known about the exact location or contents of most disposal sites on the West Coast of the U.S.

Chemical munitions used in World War II included mustard, lewisite, sarin, and tabun. When these toxic agents are exposed to seawater, they can react to form additional harmful substances: Lewisite, for example, could degrade to release arsenic near disposal sites.

Brewer’s report, published in the March 1, 2008, issue of Environmental Science & Technology, points out that chemical weapons in the ocean get little attention compared to chemical weapons disposed on land. “The ocean’s always getting shortchanged,” Brewer said.

About 500 people around the world—mostly fishermen—have been injured by the weapons since 1946. Ocean scientists are increasingly exploring and collecting samples from the seas, and could easily come in contact with these chemicals.

Off the Japanese east coast, chemical-weapons dump sites are small, shallow, close to shore, and contain large amounts of chemical weapons. The U.S. National Geospatial Intelligence Agency publishes charts of Japanese waters, but these do not include Japanese disposal sites. Many of these sites are poorly documented. Japanese fishermen have encountered the chemical agents at these sites, often with tragic results.

In Italy, more than 200 fishermen were hospitalized between 1946 and 1966 after catching chemical-weapons agents in their nets. The Italian government has since identified numerous chemical weapons sites in the Adriatic Sea. Many of these areas are routinely used for ocean research, despite the fact that sediments surrounding these sites contain mustard degradation products, and local fish have lesions and contain elevated arsenic levels.

There are 32 disposal sites off United States shores, most with poorly known contents. The locations and quantities of chemical weapons off the U.S. East Coast were documented in a 2006 article in the Bulletin of the Atomic Scientists, but sites in the Pacific Ocean were not mentioned. Similarly, a 2007 report by the Congressional Research Service only listed one site off California. According to Brewer, this illustrates the particularly acute lack of information about sites off the California coast.


This nautical chart shows the locations of seven chemical-weapons dump areas between San Francisco and the Mexican border (highlighted in brown). Some of these areas are huge. For example, the large rectangular area west of Monterey Bay is about 120 km (75 miles) by 33 km (21 miles) in size. Image modified from NOAA chart 18022.

Many of the U.S. sites are marked on nautical charts published by the National Oceanic and Atmospheric Administration. However, for navigation during research cruises, many scientists rely on other tools, such as geophysical maps and satellite images, which don’t note the sites.

“The information that should be there isn’t getting to the right people,” Brewer said. “If you’re a scientist who goes to sea to measure things, you’d like to know what’s there. These [disposal sites] are big areas, some right off Monterey.”

Even the existing disposal site markings on nautical charts are not always useful. Seven sites between San Francisco and the Mexican border encompass a total area of 4,000 square miles, about the size of Delaware. These marked areas are so large that scientists and fishers often simply ignore them. Brewer suggests the actual locations where weapons were dumped are probably much smaller and could readily be identified, but no one has done so.


This close-up view of NOAA chart 18022 shows a relatively small chemical-weapons dump area at the edge of the Gulf of the Farallones National Marine Sanctuary (whose boundary is indicated by the thick gray line). With modern technology, deep-water bottom areas are increasingly accessible to both fishers and oceanographers exploring the deep sea. Image: NOAA

As suggested by the title of Brewer and Nakayama’s report: “A plea for complete information,” Brewer believes it is time for the U.S. government to communicate openly about these toxic sites. “It’s just one of those things where society has had a blind spot,” Brewer said. “Problems that aren’t talked about never get better.”

Brewer, P. and N. Nakayama. What lies beneath: A plea for complete informationEnvironmental Science and Technology 2008, March 1, 2008, pages 1394-1399.


For additional information or images relating to this article, please contact: Kim Fulton-Bennett