The Halifax Herald Limited
Tuesday, May 20, 2003

Don't disturb submerged mustard gas, experts agree

By Dean Jobb / Staff Reporter

The best way to deal with a barge full of barrels of deadly mustard gas that lies in deep water off Sable Island may be to do nothing at all, says an American expert in the disposal of chemical weapons.

Mustard gas, a thick, tar-like liquid, can inflict serious burns on contact, but the chemical breaks down quickly into harmless compounds when exposed to water. Any effort to bring the barrels to the surface for disposal would be expensive and technically challenging, and would risk damage to the environment and human health, says a chemist with the Virginia-based consulting firm Mitretek Systems.

"These days you obviously don't want to dump it in the ocean, but the stuff that's there, it's arguably best left there," George Bizzigotti said in an interview.

"It may take hundreds of years, but eventually it will all dissolve and react with the water. . . . If you do anything else, then you really do raise issues of real risk."

A landing craft crammed with 2,850 tonnes of the gas, stockpiled by the Canadian military during the Second World War, was sunk about 334 kilometres southeast of Halifax Harbour in February 1946.

The barge and its cargo lie about three kilometres deep, far beyond the reach of divers and fishermen's trawl nets.

It's the only verified chemical weapons dump site in Canada, says Chris Hough, a Department of National Defence environmental specialist who heads a project to find and assess sites where chemical weapons and munitions were stored or dumped.

The military is seeking a private contractor to supply a submersible capable of diving to the site, photographing the wreck and taking samples of the surrounding water and sediments. There is no target date for the mission.

The environmental risk is expected to be "negligible," adds Mr. Hough, because the extreme depth makes it so inaccessible. The site is not marked on nautical charts, and the military mentions security concerns in refusing to reveal the location.

Canadian officials are aware that leaving the gas alone may be the best solution.

"There's a natural desire for people to see the government do something, but doing something on a site where there's contaminants may incur greater risk and greater problems than simply leaving them in place," says Paul Topping, a marine sediments adviser with Environment Canada who's working on the weapons project.

The plan to check out the Sable Island site is prudent, Mr. Bizzigotti says, as it will show how badly the barge and barrels have rusted and whether the cargo has remained, as he suspects, in a small area on the ocean floor.

The U.S. has undertaken similar surveys to check out dumps of military chemicals off its coasts, he says.

The gas dumped off Nova Scotia is an American formula, manufactured in Ontario and shipped to Halifax by train for disposal. It contains about 30 per cent sulphur.

The gas was used was a weapon during the First World War, inflicting burns and painful lesions on soldiers' skin and burning their lungs when inhaled.

Underwater, Mr. Bizzigotti says, it becomes a plastic-like solid that is only toxic on contact or if a person or animal comes extremely close to its surface.

"You might get one or two fish dying every now and then, but you're not going to get massive fish kills or anything like that."

The gas dissolves in water and breaks down into salt and thiodiglycol, an organic compound harmless enough to have been used as a solvent in ballpoint pen ink. It is quickly consumed by bacteria.

The Canadian dump site pales in comparison to sites in the Baltic Sea and off Italy and Japan, where hundreds of thousands of tonnes of mustard gas and other chemical weapons were dumped after the Second World War.

Sites off Sweden and Denmark are in much shallower water, at depths of 20 to 120 metres. Over the years Danish fishermen have been burned from contact with clumps of solidified mustard gas brought up in their nets.

The military will look for other sites where mustard gas may have been dumped, including an area off Victoria, B.C., where newspaper accounts say 450 tonnes was dumped in 1947.

The $9.2-million project will also see old military files scoured and rumours checked out to ensure no other chemical and biological agents were disposed of in Canada.

Another $1 million will be spent to assess 45 munitions dumps and wartime shipwrecks off the East Coast that are considered to pose the greatest potential hazard to the public.

Cleanup operations will be undertaken if warranted.

An international treaty signed in 1972 outlawed the disposal of munitions and chemicals at sea, but the dumping of dredged materials and fish waste continues under federal supervision.