March 30, 2009

Volume 87, Number 13

pp. 24-26

Lying In Wait

Researchers help U.S. Army search for chemical munitions dumped at sea

Rochelle F. H. Bohaty

USING DEEP-DIVING submersibles, researchers have confirmed the location of hundreds of munitions on the ocean floor south of Pearl Harbor. These warheads may be some of the chemical munitions the U.S. military dumped at sea nearly four decades ago.

The U.S., like other countries, used the ocean as a dump site for unwanted items, including military weapons, in the early- and mid-20th century. Poor record keeping of dump locations is creating problems for policymakers and scientists who want to find disposed-of chemical munitions to keep ensuring public and environmental well-being.

The find earlier this month off the Oahu coast by researchers from the School of Ocean & Earth Science & Technology (SOEST) at the University of Hawaii, Manoa, on behalf of the U.S. Army is likely just part of the more than 8,000 tons of chemical agents that the Army reportedly dumped off the Hawaiian shores at the end of World War II. But this cache is only a small fraction of all the munitions and bulk containers holding chemical weapons agents that were routinely scuttled in the ocean.

According to Army documents, large quantities of shells, mines, solid rocket fuels, propellants, radioactive materials, and chemical weapons were dumped into the ocean not only off U.S. shores but all around the world. And on at least 74 occasions, the Army knowingly dumped hazardous chemical agents such as mustard, lewisite, phosgene, and VX off U.S. coastlines. Records of exact locations of such dumps can be hard to find, only partly for security reasons.

"The Department of Defense disposed of excess, obsolete, or unserviceable munitions, including chemical warfare material, in coastal waters off the U.S. prior to 1970," says James C. King, the Army's assistant for munitions and chemical matters. Like questions about the location of dump sites, the exact quantities of materials disposed of at sea also remain unclear.

"On the basis of the reports we have seen, the U.S. dumped somewhere in the neighborhood of 20,000 to 25,000 tons of chemical warfare agent off the various coasts of the U.S.," says Craig E. Williams, director of the Chemical Weapons Working Group, a Berea, Ky.-based nonprofit community organization dedicated to the safe disposal of chemical weapons agents. He believes that some records may no longer be around and that the U.S. may have dumped "significantly more" chemical warfare agents than the Army reports indicate.

The first recorded instance of chemical weapons sea disposal was in 1918. Army records show that this munitions disposal was of an unknown quantity of lewisite and that it was dumped in the Atlantic Ocean somewhere between the U.S. and Britain.

The Army continued to dump chemical agents into the ocean for another 50 years until a 1969 report released by the National Academy of Sciences (NAS) criticized the practice and suggested that alternative disposal methods be explored. The following year, approximately 250 miles east of Cape Canaveral, Fla., the S.S. LeBaron Russell Briggs, loaded with sarin rockets and VX land mines, was sunk in 16,440 feet of water, marking the end of the U.S. practice of disposing of chemical weapons at sea.

In 1972, Congress codified the NAS recommendation by banning ocean dumping of many forms of waste, including warfare agents. The U.S. also signed an international agreement that forbids countries from using the ocean as a dump site. Known as the London convention, this agreement has been in force since 1975 and currently has 85 participating countries.

Although the Army stopped the practice nearly 40 years ago because of environmental and safety concerns, it has done little since then to investigate the status of the chemical weapons that the world's military organizations had already dumped onto the ocean floor.

Of concern is that no one knows whether these weapons are still active or whether they have degraded over time. Even if the dump locations were on record, materials could have been moved over time by underwater currents.

MANY PEOPLE, including members of Congress, have taken interest in learning more about the military's ocean-dumping practices, as well as the health and environmental impacts of these dumps. For this reason Congress required DOD to conduct a historical review of all available records to determine the number, size, and location of sites in which the military disposed of munitions in U.S. coastal waters.

Recently, DOD contracted the University of Hawaii to assess the location, condition, and potential risks of a chemical weapons disposal site near Pearl Harbor. DOD has a long list of munitions it says were dumped somewhere in this area, but "the problem is that where exactly is not well established," says Margo H. Edwards, director of the Hawaii Mapping Research Group at SOEST.

To locate military munitions, including chemical ones, Edwards and her team of researchers are taking a closer look at the seafloor using two manned deep-diving submersibles and one remotely operated vehicle. Specifically, the researchers are investigating "long trails of highly reflective small targets" resting on the ocean floor, Edwards says.

These reflective objects were identified by her group in August 2007 with side-scan sonar, a common technique used to image the seafloor to make maps and identify objects resting there. The detected trails are located 3 to 7 miles south of Pearl Harbor, Edwards notes. At approximately 3 to 6 feet long, the reflective targets, or "speckles," are located in water between 900 and 1,500 feet deep, she adds.

Such trail patterns are the result of the technique used to dispose of the material. Specifically, once the transport vessel was far enough out to sea, warheads and canisters containing bulk chemical agents were pushed overboard one after another. The containers settled on the ocean floor, littering it with a cookie-crumb-like trail of hazardous materials.

Since March 3, Edwards and her research team, along with their military and commercial partners, have been able to get a close enough look at the speckles to identify them as military munitions. Many of the munitions observed are "multipurpose containers, but encrustation and deterioration make it difficult" to see what is painted on them to know exactly what type of chemicals are inside, she says. Edwards and the Army's King both acknowledge that these munitions could contain chemical weapons agents.

"There is lots of rust," according to Edwards. Such corrosion not only makes it hard to identify the contents of these containers, but it also raises concern about their integrity. For munitions containing chemical agents, the fear is that dated chemical munitions sitting on the ocean floor are leaking or will begin to leak their toxic contents.

Because most of the chemical agents were encased in some sort of metal container when disposed of many years ago, it is possible that the agents are still active, says Peter G. Brewer, a geochemist and senior scientist at the Monterey Bay Aquarium Research Institute, in California. Brewer is one scientist who has worked on gaining a better understanding of what happens to the chemical agents when they leak out of containers at the bottom of the ocean.

Typically, in seawater chemical weapons agents undergo significant dissolution and rapid hydrolysis. "This is because these loathsome compounds are designed to be highly reactive, and they hydrolyze quickly on contact with water to break down into products that are unpleasant but far less harmful," he notes.

Although chemicals such as sarin, a nerve agent, undergo rapid hydrolysis to produce hydrogen fluoride and isopropylmethylphosphonate, other agents are more persistent. Mustard and other sulfur-containing weapons agents are thought to be less soluble and hydrolyze more slowly. Few studies have been conducted on exactly how chemical weapons agents break down in deep-ocean conditions. In addition, the environmental effects of the breakdown products remain unknown. "In general, the broad impacts are surprisingly small, but the very local ones are intense," Brewer says.

THE RISK is not just to marine life and the ocean environment. Approximately 500 people, mostly fishermen, have been injured by submerged weapons since 1946. Most commonly, fishermen are exposed when they pull up these munitions or canisters in their nets and come in direct contact with the chemicals.

Another unsuspecting group of people who could come into contact with these materials are ocean scientists. They are increasingly exploring and collecting samples from the seas and could easily come into contact with these chemicals, Brewer says. He thinks more detailed maps of dumped weapons should be drawn up and made available to such people.

In Hawaii, Edwards and her collaborators are still working to determine whether the located munitions contain chemical agents. The sediment and water samples they collected will be thoroughly tested, Edwards says. Representatives from the Army will also examine the images collected by the research team, she says.

Currently, there are no plans to bring these munitions to the surface for inspection or remediation purposes. Remediation plans are likely to change once the condition and location of dumped munitions are determined. Edwards says her team plans to continue working with the Army to locate other munitions off Hawaiian shores.

Scene 1: Water Sample Collection

Researchers use robotic arms to collect water samples near munitions located off Pearl Harbor.

Scene 2: Sediment Sample Collection

Researchers collect sediment samples near munitions.

Scene 3: Munitions Located Near Pearl Harbor

Researchers locate several munitions lying on the ocean floor.

Chemical & Engineering News

ISSN 0009-2347

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