This research explores opportunities for a more comprehensive assessment process using the ongoing and contentious Environmental Assessment (EA) of the Enbridge Northern Gateway pipeline project in western Canada. Research on EA in Canada has demonstrated considerable challenges in effectively engaging participants throughout the assessment process. Research suggests that the inability to engage with stakeholders in EA adversely affects the quality of information considered, the integrity of the process, and the legitimacy of EA outcomes. This represents a fundamental challenge for EA, as effective assessment processes are needed to adequately evaluate increasingly complex and contentious projects. Strategies that encourage comprehensive stakeholder engagement in decision making for contentious environmental issues have been identified as being central in generating more thorough and legitimate outcomes, and can produce social learning and other benefits. The study considers insights obtained from literature on collaborative planning, rationality, and sustainability science as well as interviews with EA participants and researchers to pursue that aim. The study reveals common ground that highlights stakeholder equality and cooperation, objectivity and legitimacy, transparency and trust, and the agenda, timing, structure and design of the decision-making process as important in fostering a more comprehensive assessment in this context. Linkages between respondent views about collaboration in the EA process and contemporary interpretations of rationality are also discussed and suggests that further research exploring collaborative strategies that are inspired by these ideas is likely to be fruitful. Finally, the study offers recommendations for decentralized and collaborative process in advance of the project application that encourages consensus, participant equality, and open debate
