In the wake of the release of its report, Opening the Door for Oil Sands Expansion: The Hidden Environmental Impacts of the Enbridge Gateway Pipeline, the Pembina Institute wrote this letter to Jim Prentice, Minister of the Environment, and Peter Sylvester, president of the Canadian Environmental Assessment Agency. In the letter, Pembina calls on the government to amend the terms of reference for the environmental assessment to include the upstream impacts of the proposed pipeline.