Greenpeace and the World Wildlife Fund have sent letters to international and Canadian companies asking how they manage public communication on climate change.
They say spreading misinformation could leave company officers open to legal liability.
Keith Stewart of Greenpeace Canada says the letters are the first step in a long-term campaign to use the law to prevent the energy industry from delaying action on climate change.
He says the strategy was inspired by the ultimately successful campaign to make tobacco companies liable for sowing doubt about the health effects of their products.
The letter has been sent to five Canadian companies: Suncor (TSX:SU), Talisman Energy (TSX:TLM), Husky Energy (TSX:HSE), EnCana (TSX:ECA) and Canadian Natural Resources (TSX:CNQ).
It has also gone out to 45 multinationals, including many with operations or subsidiaries in Canada.