A resident of Cape Breton Island wants the Canadian military to come clean about where tonnes of chemical weapons were dumped after the Second World War.

Myles Kehoe, an antique dealer in Margaree Forks, Cape Breton, was surprised at what he found while looking at some nautical charts from the 1960s.

Some of the charts mark well-documented military explosive dump sites off the East Coast. But one marked a site not found on any others.

Maj. Francois Lauzon

Kehoe says a former military person and local fishermen have told him it's a post-Second World War chemical warfare dump.

The military claims it doesn't know what it is, but is looking into the allegations.

"We're taking Mr. Kehoe's claims very seriously," said Maj. Francois Lauzon.

In 1946, the navy sunk a barge-load of mustard gas 160 km east of Halifax, near Sable Island.

The military is trying to find out if there are other sites. It admits it doesn't know.

"Some records may have been destroyed and it will make the search that much more complicated," said Lauzon. "But we will do our best."

Opposition politicians are starting to ask questions on Parliament Hill.

"We're asking the government to come clean with Canadians, to be responsible, to protect the interests of all of us, and our fish stocks," said Peter Stoffer, NDP fisheries critic. Kehoe believes the waters off Cape Breton hide other unmarked mustard gas dump sites.

"It's there. They have to admit it's there. If you manufacture something, and you don't use it, where the heck is it?," he said. "Now if they can show me where it's at, in another site, hey, all the better."

Kehoe is worried that with increased exploration of the ocean floor by oil companies and others old warheads and barrels of mustard gas could be disturbed, with dangerous results.