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Studies have found high levels of polyaromatic hydrocarbons in smoked fish.DARRYL DYCK/The Canadian Press

Two University of British Columbia researchers are trying to find out whether the way First Nations in British Columbia have been smoking salmon for generations is actually carcinogenic.

But B.C.'s deputy provincial health officer is urging caution, saying one of the unintended consequences of such a study is to cause aboriginal people to mistrust their own traditional foods.

A research project being led by David Kitts and Kevin Allen – food scientists in the food, nutrition and health program at UBC – is looking at the presence of cancer-causing chemicals in smoked salmon prepared in old-style wood smokehouses.

Cooking wild game or fish in these smokehouses requires extreme heat, which can result in polyaromatic hydrocarbons tainting the fish.

Previous studies have shown that high levels of polyaromatic hydrocarbons like benzo(a)pyrene – a cancer-causing chemical – are found in smoked fish.

Benzo(a)pyrene is a byproduct of incomplete combustion and is found in cigarette smoke, grilled and broiled foods, gasoline and wood.

The study will test and evaluate the fish down to the microbial level to determine exactly how high the toxicity levels are.

"There is a threshold that we accept and there is a threshold that we get concerned about," Dr. Kitts said. "When a concentration goes above that threshold in a food system or an environmental space, then flags go up."

Initial tests run by Dr. Kitts revealed that traditional methods of smoked preservation – where a longer duration "full smoke" is used – had higher levels of benzo(a)pyrene that were "equal to or higher than the target level of safety."

The two researchers have partnered with the Lake Babine Nation and Nee Tahi Buhn, two First Nations communities in Burns Lake, B.C., where community members eat traditionally preserved foods such as smoked salmon.

Dr. Evan Adams, B.C.'s deputy provincial health officer and senior medical adviser to the First Nations Health Authority, said scientists involved in this kind of research must tread carefully.

"We receive a number of questions from First Nations communities asking around the safety of their traditional foods – it's a very common question," said Dr. Adams, who is from the Sliammon Band near Powell River. "We spend a lot of time reassuring them that their traditional foods are safe and healthy."

Dr. Kitts said one option for reducing the carcinogenic risks associated with smoking salmon is to use modern smokehouses with an external generator that allows control over temperatures and smoking time. Smoking salmon in wood-framed smokehouses, he said, is not a "controlled process."

But Dr. Adams said electric smokehouses are not sustainable and should not be considered as an alternative to traditional methods.

He said a more participatory approach to such studies in which they are co-led with First Nations would ensure that the research agenda is driven by the concerns of communities and not by "individuals."

"If you ask a community what their concerns are for the people, diabetes and cancer would make the list," Dr. Adams said, "but polyaromatic hydrocarbons wouldn't."

"Alcohol, cigarettes, lousy food and lack of exercise kill a lot of people," Dr. Adams said, "but I have never heard of a polyaromatic hydrocarbon killing a First Nations."

Derrick George has been smoking salmon in traditional wood-framed smokehouses that he builds with his own hands for nearly 40 years and he is skeptical of the study.

For Mr. George, preserving salmon through this method is more than just a long-held tradition. In the past, it provided sustenance through the winter for the hundreds of members of the Tsleil-Waututh First Nation.

"I don't know anybody that's died of cancer from my smoked salmon. I don't think I would stop. I've got it perfected and I'm teaching my boys."

The results of the research will be released when the study concludes in June, 2015.