The 35 chiefs say the pipeline that would carry oil sands crude from Alberta through B.C. to the coast at Kitimat would be too environmentally dangerous.
Dene National Chief Bill Erasmus says they are worried about pollution from pipeline spills, noting a recent spill from an Enbridge pipeline near Norman Wells.
He says there have been more than 100 pipeline spills and accidents recorded in Canada in the past few years.
Mr. Erasmus also says the oil sands contribute to climate change, which he says is hurting aboriginal communities, culture, and their traditional ways of life.
Enbridge says the $5.5 billion will create 100’s of jobs and generate millions of dollars in taxes to local, provincial and federal governments.
If approved, construction would begin in 2013.