Canadian sailors may have been exposed to a 'toxic soup' of chemicals while aboard a submarine that caught fire, navy officials said Thursday.

The Halifax-based crew was told Wednesday night that they came into contact with the chemicals during a fire aboard the HMCS Chicoutimi in 2004, said Cmdr. Jeff Agnew.

"It was a very thick, dangerous, toxic smoke," he said.

There were 55 sailors on board at the time. Three crew members were airlifted to hospital for treatment. Lt. Chris Saunders of Halifax did not survive his injuries.

Navy officials said a toxicology test found the fumes held several poisonous toxic components including carbon monoxide and Peridite, a known carcinogen.

However, navy Capt. Bill Woodburn, chief of staff of the Maritimes Forces, said any serious health concerns would already have appeared.

"If there were any side-effects or conditions that could have resulted from the fire onboard Chicoutimi it would most likely have started to manifest itself very early on," he told reporters.

Agnew said it's also unlikely crew members will develop cancer because of exposure to the chemicals.

"In the longer term, we think the chances of an illness as a result of the Chicoutimi fire are slim to none," he said.

Investigators looking into the incident discovered that Peridite burned when water flooded into the submarine, starting an electrical fire in the commanding officer's cabin.

The fire broke out while the crew was on its way to Halifax from Faslane, Scotland on Oct. 4, 2004.

With a report by CTV Atlantic's Rick Grant and files from The Canadian Press